Best Practices in Developing 
Proprietary Names for Human 
Prescription Drug Products
 
 
Guidance for Industry
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Drug Evaluation and Research (CDER) 
Center for Biologics Evaluation and Research (CBER) 
 
 
December 2020 
Drug Safety
   
Best Practices in Developing 
Proprietary Names for Human 
Prescription Drug Products
 
Guidance for Industry
 
 
 
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guidances 
 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Drug Evaluation and Research 
Center for Biologics Evaluation and Research 
 
December 2020 
Drug Safety 
 
  Contains Nonbinding Recommendations 
 
 
Table of Contents 
 
 
I.  INTRODUCTION............................................................................................................. 1 
II.  BACKGROUND ............................................................................................................... 2 
III.  PRESCREENING PROPOSED PROPRIETARY NAME FOR ATTRIBUTES 
THAT ARE LIKELY TO CONTRIBUTE TO MEDICATION ERRORS ................ 4 
A.  Obvious Similarities in Spelling and Pronunciation of Proprietary Names ................ 5 
B.  Inert or Inactive Ingredients ............................................................................................ 5 
C.  Combinations of Active Ingredients ................................................................................ 5 
D.  USAN Stems ...................................................................................................................... 5 
E.  Brand Name Extensions ................................................................................................... 6 
F.  Reuse of Proprietary Names ............................................................................................ 7 
G.  Use of Letters and Numbers That Are Unpronounceable as a Word in Proprietary 
Names ................................................................................................................................. 8 
IV.  ADDITIONAL BEST PRACTICES FOR EVALUATION OF PROPOSED 
PROPRIETARY NAME .................................................................................................. 8 
A.  Names That Include Reference to Product-Specific Attributes ................................... 8 
B.  Medical Abbreviations...................................................................................................... 9 
C.  Modifiers as Components of a Proprietary Name ......................................................... 9 
D.  Dual Proprietary Names................................................................................................. 14 
E.  Proprietary Names of Drug Products Marketed Outside the United States ............. 15 
F.  Incorporation of the Sponsors Name ........................................................................... 15 
V.  FURTHER BEST PRACTICES FOR REVIEW, INCLUDING FOR 
MISBRANDING AND OTHER LEGAL CONCERNS .............................................. 15 
VI.   RECCOMENDED METHODS FOR EVALUATING RISKS OF MEDICATION 
ERROR POSED BY SIMILARITY OF A PROPOSED PROPRIETARY NAME 
TO OTHER NAMES ...................................................................................................... 17 
A.  Name Simulation Studies ............................................................................................... 17 
B.  Obtain Medication Error Data for Names That Are Already Marketed .................. 18 
C.  Computational Method To Identify Names With Potential Orthographic, Spelling, 
and Phonetic Similarities ................................................................................................ 18 
D.  Safety Determination of Names With Potential Orthographic, Spelling, and 
Phonetic Similarities ....................................................................................................... 20 
GLOSSARY................................................................................................................................. 22 
 
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  Contains Nonbinding Recommendations 
 
DATABASES AND OTHER RESOURCES ............................................................................ 25 
APPENDIX A:  EXAMPLES OF PREVIOUSLY USED MODIFIERS AND THEIR 
COMMONLY UNDERSTOOD MEANINGS ............................................................. 28 
APPENDIX B:  RESEARCH METHODOLOGY FOR CONDUCTING ............................ 33 
  MISBRANDING REVIEW ............................................................................................ 33 
APPENDIX	C:		RESEARCH METHODOLOGY CONSIDERATIONS FOR 
CONDUCTING NAME SIMULATION STUDIES .................................................... 37 
APPENDIX D:  HIGHLY SIMILAR NAME PAIR CHECKLIST ....................................... 36 
APPENDIX E:  MODERATELY SIMILAR NAME PAIR CHECKLIST .......................... 40 
APPENDIX F:  LOW SIMILARITY NAME PAIRS ............................................................. 42 
 
 
 
 
   
 
ii  Contains Nonbinding Recommendations 
 
Guidance for Industry1 
 
Best Practices in Developing Proprietary Names for Human 
Prescription Drug Products 
 
 
This guidance represents the current thinking of the Food and Drug Administration (FDA or Agency) on 
this topic.  It does not establish any rights for any person and is not binding on FDA or the public.  You 
can use an alternative approach if it satisfies the requirements of the applicable statutes and regulations.  
To discuss an alternative approach, contact the FDA office responsible for this guidance as listed on the 
title page.   
 
 
 
I.  INTRODUCTION 
 
FDA is issuing this guidance to help sponsors of human prescription drug products2 develop 
proprietary names3 for those products.  This guidance describes best practices to help minimize 
proprietary name-related medication errors and otherwise avoid adoption of proprietary names 
that contribute to violations of the Federal Food, Drug, and Cosmetic Act (FD&C Act) and its 
implementing regulations.  It also describes the framework FDA uses in evaluating proposed 
proprietary names that is also available to sponsors to use before submitting names for FDA 
review if they wish. This guidance does not address the designation of established names or 
proper names. 
 
This guidance applies to all human prescription drug products.  In this guidance, all such 
products are jointly referred to as products, and persons responsible for developing the products 
are referred to as sponsors. 
 
FDA is separately developing guidance on best practices in developing proprietary names for 
nonprescription drug products.4 
                                                 
1 This guidance was prepared by the Office of Surveillance and Epidemiology, Division of Medication Error 
Prevention and Analysis, and the Office of Prescription Drug Promotion in the Center for Drug Evaluation and 
Research (CDER), and the Advertising and Promotional Labeling Branch in the Center for Biologics Evaluation and 
Research (CBER) at the Food and Drug Administration. 
2 For purposes of this guidance, unless otherwise specified, references to drugs and drug products include drugs 
submitted for approval or approved under section 505 of the FD&C Act (21 U.S.C. 355) and biological products 
licensed under section 351 of the Public Health Service Act (42 U.S.C. 262), other than devices regulated under a 
biologics license application. 
3 Terms that appear in bold type upon first use are described in the Glossary, as they are used in this guidance. 
4 See the FDA draft guidance for Industry Best Practices in Developing Proprietary Names for Human 
Nonprescription Drug Products (December 2020) for design practices to help minimize errors with nonprescription 
proprietary names. We update guidances periodically. For the most recent version of a guidance, check the FDA 
Drugs guidance web page, available at  
https://www.fda.gov/RegulatoryInformation/Guidances/default.htm.   
When final, this guidance will represent the Agencys current thinking on this topic. 
 
1 
  Contains Nonbinding Recommendations 
 
This guidance is intended to provide clarity and transparency to sponsors on the factors and 
systematic framework FDA uses to evaluate proposed proprietary names for prescription drugs 
and to recommend best practices for sponsors considering such names.  Using the best practice 
recommendations and other assessment tools addressed in this guidance is not mandatory, and 
applying them does not dictate specific outcomes.  Assessments of a proprietary name are 
necessarily fact-specific, and therefore, FDAs determinations are made on a case-by-case basis, 
considering the totality of the information. 
 
In general, FDAs guidance documents do not establish legally enforceable responsibilities.  
Instead, guidances describe the Agencys current thinking on a topic and should be viewed only 
as recommendations, unless specific regulatory or statutory requirements are cited.  The use of 
the word should in Agencys guidance means that something is suggested or recommended, but 
not required. 
 
 
II.  BACKGROUND 
 
Selecting a proprietary name is a critical element in drug product design and development 
because end users may rely, in part or in whole, on the proprietary name to identify which 
product, among thousands of available products, is intended for or used by a particular patient.  
Proprietary names of drug products are commonly used by physicians and other health care 
professionals to prescribe or discuss a drug, and for this reason, accurate identification by the end 
user is essential.  If end users cannot easily distinguish a proprietary name from other drug 
names that are similar phonetically (sound-alike names) or in their spelling or orthographic 
appearance (look-alike names), or if the drug name is otherwise confusing or misleading, the 
patient might receive the wrong product, or it might not be possible to correctly identify the 
product used. 
 
A report released in 1999 by the Institute of Medicine (IOM) described medication errors as a 
significant public health concern that accounts for an estimated 7,000 deaths annually in the 
United States.5  The report recommended that FDA encourage pharmaceutical companies to test 
proposed proprietary names to identify and remedy potential sound-alike and look-alike 
confusion with existing drug names.6  In July 2006, the IOM published a follow-up report titled 
Preventing Medication Errors, which emphasized in part that proprietary name design should 
focus on end users needs and understanding and urged FDA to apply the principles of cognitive 
and human factors engineering to the selection and evaluation of proprietary names.7,8 
                                                 
5 IOM, 1999, To Err Is Human: Building a Safer Health System. Institute of Medicine, National Academies Press: 
Washington, DC, 2000  
6 IOM, 1999, To Err Is Human: Building a Safer Health System. Chapter 7, Recommendation 3, p. 136.  The IOM 
recommendations were consistent with an earlier FDA report that likewise underscored the importance of reducing 
errors from proprietary name confusion. HHS/FDA Report to FDA Commissioner from the Task Force on Risk 
Management titled Managing the Risks from Medical Product Use (May 10, 1999).  
7,8 IOM, 2006, Preventing Medication Errors, Institute of Medicine, National Academies Press: Washington, DC, 
2000, Chapter 6, Recommendation 4, p. 274. pp. 281-282. 
 
 
2 
  Contains Nonbinding Recommendations 
 
As FDA has long recognized, and addressed on numerous occasions in recent decades, confusion 
involving proprietary names can cause or contribute to significant medication errors.9  Our focus 
has been to develop and communicate to sponsors a systematic, standardized, and transparent 
approach to proprietary name evaluation within the product development, review, and approval 
process.  As part of this initiative, FDA held public meetings in June and December of 2003 to 
discuss the methods used for proprietary name evaluation.  In 2007, FDA formally committed to 
certain performance goals, including implementing evaluation measures to help reduce medication 
errors related to look-alike and sound-alike proprietary names (PDUFA IV) and in 2012 
implemented BsUFA performance goals10,11  In 2008, the Agency held another public meeting to 
further discuss testing and evaluating proprietary names. 
 
This guidance, which we are issuing in partial fulfillment of the PDUFA IV performance goals, 
presents FDAs current thinking on best practices for developing and selecting proposed 
proprietary names. 
 
Proprietary names are used in a products label and labeling12, including promotional labeling.  
A drugs labeling, in turn, is often a key element in FDA oversight.  For example, under section 
502(a) of the FD&C Act (21 U.S.C. 352(a)), a drug is misbranded if its labeling is false or 
misleading in any particular. Section 201(n) of the FD&C Act (21 U.S.C. 321(n)) sets forth 
certain considerations that shall be taken into account when determining whether labeling is 
misleading.  FDA regulations also address some of the ways in which the name of a drug may 
render its labeling misleading.13  In addition, labeling is relevant to determining whether a drug 
is a new drug under section 201(p) of the FD&C Act (21 USC 321(p)), for which premarket 
approval is required (see sections 505(a) and 301(d) of the FD&C Act (21 U.S.C. 355(a) and 
331(d)). 
 
                                                 
9 Smetzer, JL, and MR Cohen., 2007, The role of drug names in medication errors, in MR Cohen, Medication 
Errors, 2nd ed., Washington, DC: American Pharmacists Association, pp. 87-110. 
10 These performance goals and commitments were undertaken in connection with the reauthorization and expansion 
of the Prescription Drug User Fee Act (PDUFA IV reauthorization), which was signed into law on September 27, 
2007, as part of the Food and Drug Administration Amendments Act of 2007 (FDAAA) (Public Law 110-85).  For 
more information on FDAs PDUFA IV performance goals, see FDAs website at  
https://www.fda.gov/ForIndustry/UserFees/PrescriptionDrugUserFee/ucm145390.htm. 
11 These performance goals and commitments were undertaken in connection with the authorization of the 
Biosimilar User Fee Act (BsUFA).  For more information on FDAs BsUFA performance goals, see FDAs website 
at https://www.fda.gov/industry/fda-user-fee-programs/biosimilar-user-fee-amendments  
12 Labeling includes the prescribing information, container labels, carton labeling, and FDA-approved patient 
labeling. 
13 See, e.g., 21 CFR 201.6(b), stating that labeling for a drug containing two or more ingredients may be misleading 
if the name of the drug designated in that labeling includes or suggests the name of one or more but not all of the 
ingredients; 21 CFR 201.10(c)(3), stating that labeling of a drug may be misleading if it employs a fanciful 
proprietary name for a drug or ingredient that implies some unique effectiveness or composition when the drug or 
ingredient is in fact a common substance, the limitations of which are readily recognized when the drug or 
ingredient is listed by its established name; 21 CFR 201.10(c)(5), stating that labeling of drug may be misleading if 
the proprietary name may be confused with the proprietary name or established name of a different drug or 
ingredient because of similarity in spelling or pronunciation.   
 
3 
  Contains Nonbinding Recommendations 
 
FDA reviews a proposed proprietary name as part of a prescription drug products labeling 
through the application review process for the product.14  Although PDUFA and BsUFA 
performance goals provide for the Agency to make a tentative determination of acceptance or 
non-acceptance of a proposed proprietary name early in the review process (in instances where 
the proprietary name review request is submitted as a complete submission), final acceptance of 
a proposed proprietary name occurs as part of the approval of the drug product.  Each name is 
evaluated on a case-by-case basis.   
 
Sponsors have an ongoing obligation to ensure that each marketed product satisfies applicable 
requirements, such as ensuring that its labeling is not false or misleading in any particular (see 
section 502(a) of the FD&C Act).  If a marketed products proprietary name causes or 
contributes to medication errors, the sponsor of that product should work expeditiously with 
FDA to resolve the situation.  If the product does not comply with applicable requirements and 
the sponsor is unwilling to address or resolve an issue voluntarily, the sponsor may be subject to 
enforcement actions. 
 
The sections below outline considerations for developing and evaluating a proposed proprietary 
name, which are described in greater detail in this guidance.  Sections III and IV focus on 
evaluating factors within the name or related to the naming strategy that are likely to contribute 
to medication errors.  Section V provides our recommendations for evaluating the proposed 
proprietary name to help ensure compliance with FDA-administered statutory and regulatory 
provisions, and section VI describes our current thinking on evaluating the proposed proprietary 
names for look-alike and sound-alike risks. 
 
For each category, we believe that no single test or standard is adequate to determine whether a 
proposed proprietary name may contribute to errors or otherwise contribute to any violation of 
the FD&C Act.  Rather, the current approach to proposed proprietary name evaluation uses a 
combination of different and complementary tests. 
 
 
III.  PRESCREENING PROPOSED PROPRIETARY NAME FOR ATTRIBUTES 
THAT ARE LIKELY TO CONTRIBUTE TO MEDICATION ERRORS 
 
This section identifies attributes of proposed human prescription drug product proprietary names 
that FDA typically finds concerning and that generally can be identified through prescreening by 
sponsors.  We recommend that sponsors screen proposed proprietary names for the attributes 
described below as a first step before proceeding with a full assessment of whether a name is 
likely to contribute to medication errors or otherwise contribute to violations of the FD&C Act.  
We recommend that sponsors avoid proposed human prescription drug product proprietary 
names that raise concerns during preliminary screening.  The sections below explain FDAs 
thinking on each of these aspects. 
 
 
                                                 
14 See FDAs guidance entitled Contents of a Complete Submission for the Evaluation of Proprietary Names, 
dated April 2016, available at https://www.fda.gov/media/72144/download. 
4 
  Contains Nonbinding Recommendations 
 
A.  Obvious Similarities in Spelling and Pronunciation of Proprietary Names 
 
FDA recommends that sponsors avoid proposed proprietary names that are similar in spelling or 
pronunciation to existing proprietary names, established (or proper) names, or names of 
ingredients of other products.  A drugs labeling may be misleading if its proprietary name is 
similar in spelling and/or pronunciation such that it may be confused with the proprietary name 
or the established name of a different drug or active ingredient (see  201.10(c)(5) (21 CFR 
201.10(c)(5))).  FDA uses the Phonetic and Orthographic Computer Analysis (POCA) tool to 
determine the similarity between names as detailed in section VI.C.  Research has shown that 
names involved in postmarketing medication errors generally have a higher degree of 
similarity.15  Based on this research and our postmarketing experience, names with high 
similarity scores are more likely to result in confusion.  Generally, names that are nearly 
identical in spelling and/or pronunciation generate a similarity score of 70% or higher on the 
POCA tool.16 
 
B.  Inert or Inactive Ingredients 
 
We recommend that proposed proprietary names not incorporate any reference to an inert or 
inactive ingredient (as defined in  210.3(b)(8) (21 CFR 210.3(b)(8))), because doing so may 
create a misleading impression that the ingredients value is greater than its true functional role 
in the formulation (see, e.g.,  201.10(c)(4)). 
 
C.  Combinations of Active Ingredients 
 
FDA recommends against proprietary names of fixed combination drug products that include or 
suggest the name of one or more, but not all, of its active ingredients (as defined in  
210.3(b)(7)), because such names can mislead the end user by implying that the product contains 
only the ingredient or ingredients included in, or suggested by the name (see 21 CFR 201.6(b) and 
section 201(n) of the FD&C Act). 
 
D.  United States Adopted Name Stems 
 
We recommend that sponsors avoid proprietary names that incorporate United States Adopted 
Name (USAN) stems in the position that USAN designates for the stem in a nonproprietary or 
established name.  USAN stems are intended to indicate a pharmacological or chemical trait of a 
drug, and a single stem may be applicable to multiple drug products.  Using these stems in the 
position designated by USAN within the proprietary names, when used inconsistently with the 
intended USAN meaning, may imply that a product has a pharmacological or chemical trait that 
it does not.  Even when using these stems within the proprietary names is consistent with the 
USAN meaning, it can result in the creation of multiple similar proprietary names and/or 
proprietary names that are similar to the nonproprietary or established names for other drug 
                                                 
15 Lambert, BL, S-J Lin, K-Y Chang et al., 1999, Similarity as a risk factor in drug-name confusion errors: The look-
alike (orthographic) and sound-alike (phonetic) model, Medical Care,  37(12):12141225. 
16 POCA Program, available at http://www.fda.gov/Drugs/ResourcesForYou/Industry/ucm400127.htm.  
 
5 
  Contains Nonbinding Recommendations 
 
products, leading to an increased risk of medication errors.  We recommend as best practice that 
sponsors screen proposed proprietary names against the stem list created by the USAN Council 
to ensure that a USAN stem is not present in the stem position in the proprietary name.17 
 
However, FDA is less concerned about USAN stems that consist of two letters in proprietary 
names and would generally not object to their use.  The two-letter stems are often not distinct 
enough to be recognized as USAN stems.  Also, some two-letter stems are outdated and have not 
been used by the USAN Council for years.  There are currently five stems that consist of two 
letters as identified by the USAN Council.18 
 
Two-letter stems have very few associations and, in some cases, are rarely used (e.g., ac last 
used by USAN Council in 1997 (nepafenac); -aj- only used once by USAN Council in 1976 for 
lorajmine).  We also note that USAN has used some of the two-letter stems in established names 
(vortioxetine, afoxolaner), as well as included them in other stems (-tioxetine) that are 
inconsistent with the cited stem definition.  This has resulted in conflicting stems, and therefore, 
in those instances, the stem does not support the USAN Council naming system or accurately 
indicate the pharmacological or chemical trait of the drug.  Additionally, based on our 
postmarketing experience, the two-letter stems have not raised similar safety concerns that we 
have identified with longer stems.19 
 
FDA generally would not object to the inclusion of letters found within a USAN stem but located 
within a position not reserved by USAN for the stem in a nonproprietary or established name, 
because this likely would not create the same degree of risk for confusion as those names that 
have the stem in the USAN-designated position. 
 
In some cases, FDA may find a proposed proprietary name acceptable even if it includes a 
USAN stem in the USAN-designated position.  Such circumstances could arise if the proposed 
name includes a word that can only be spelled in the English language using a stem in the 
position designated by USAN.  For example, if a proposed proprietary name includes the word 
congestion, using the letters gest, which are a USAN stem, is unavoidable. 
 
E.  Brand Name Extension 
 
In this guidance, FDA uses the term brand name extension to refer to a naming strategy that 
uses a proprietary name that is already associated with one or more marketed drug products, with 
or without a modifier, for a product that does not share any active ingredient(s) or active 
moiety(ies) with the marketed product(s).  Two examples of what FDA considers as brand name 
extensions are: 
 
                                                 
17 See the list of approved USAN stems, available at: https://www.ama-assn.org/about/united-states-adopted-
names/united-states-adopted-names-approved-stems, last acessed 12/10/19 
18 -ac: anti-inflammatory agents (acetic acid derivatives); -aj-: antiarrythmics (ajmaline derivatives); ef-: Fc fusion 
protein; -fo-: phosphoro derivatives; and io-,-io-: iodine containing contrast media (accessed April 2, 2019). 
19 Institute for Safe Medication Practices, 2003, Safety briefs: Aripiprazole or rabeprazole?, ISMP Med Saf Alert 
Acute Care, 8(8):1-3; 
Institute for Safe Medication Practices, 2002, Safety Briefs, ISMP Med Saf Alert Acute Care, 7(17):1-2. 
6 
  Contains Nonbinding Recommendations 
 
1.  The proprietary name Drugname is already associated with a marketed product that 
contains a specific active ingredient or active moiety, and the sponsor uses the same 
proprietary name Drugname, with or without a modifier, to introduce a new product 
that does not contain that same active ingredient or active moiety. 
 
2.  A sponsor uses a portion of the proprietary name already associated with a marketed drug 
product (e.g., the use of a shared prefix letter string with a modified suffix letter string, 
whereby the prefix letter string evokes the proprietary name already associated with a 
marketed drug product), with or without a modifier, to introduce a new product that does 
not contain the same active ingredient or active moiety. 
 
FDA advises against using brand name extension to introduce a new product.  Health care 
professionals familiar with an existing product may, in some cases, equate that products 
proprietary name with the products active ingredients (or active moieties) or uses. 
 
In some cases, using the same proprietary name that is already associated with another marketed 
drug product has led to the use of a product for the wrong indication, in the wrong patient 
population, at the wrong dose, or in a contraindicated manner.  Some of the errors caused by 
these types of name confusions have resulted in serious adverse events when patients were 
erroneously medicated with an active moiety that was not intended to be administered. 
 
F.  Reuse of Proprietary Names  
 
FDA recommends that sponsors refrain from using the proprietary name of a product that is no 
longer marketed to name a different drug product, because there is a strong risk that end users 
may continue to associate the name with the original discontinued product.  Prescribers often 
continue to use the proprietary name of discontinued products.  For example, when prescribing a 
drug for which there are marketed generics, prescribers may refer to the proprietary name of the 
discontinued brand version.20  Proprietary names associated with discontinued drug products also 
may continue to appear in drug product reference texts and electronic media for extended periods 
of time. 
 
If proprietary names are proposed for reuse, FDA will assess them on a case-by-case basis, 
considering factors that might establish the drug name familiarity, including length and extent of 
product distribution, the existence (or lack thereof) of past or current generic equivalents, and 
data that might otherwise show health care professional familiarity with the drug name.  If a 
sponsor chooses to use this approach in naming, we recommend sponsors consider the above 
factors and provide data to support that reusing the proprietary name of a discontinued product 
will not be problematic. 
 
Note that in its evaluation of the proposed proprietary name for a new product, FDA does not 
consider a proposed name to be reused if it is one that FDA previously found acceptable for a 
                                                 
20 Tu, CM, K Taylor, and G Chai. Use of proprietary names by prescribers for discontinued brand drug products 
with existing generic equivalents, Drug Information Journal (published online August 21, 2012), available at 
http://dij.sagepub.com/content/early/2012/08/21/0092861512456282.full.pdf+html, last accessed 12/10/19 
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  Contains Nonbinding Recommendations 
 
different product, but that was never used to market that earlier product.  If submitted anew, 
FDA will evaluate the acceptability of the name for the new product. 
 
G. Use of Letters and Numbers That Are Unpronounceable as a Word in Proprietary 
Names 
 
Generally, as a best practice, proprietary names should be pronounceable as a word because 
proprietary names are used by health care professionals when prescribing, ordering, transcribing, 
dispensing, and administering drugs, and when counseling patients on their medications.  We 
discourage sponsors from proposing proprietary names that consist of a mixture of letters or 
numbers placed together (e.g., IVS458).  Such names may not be understood as drug names that 
are typically composed of letters only, or they could be misconstrued as another element 
associated with the drug product or prescription, such as dose or route of administration.  Names 
constructed in this manner could lead to medication errors depending on the nature of the 
misinterpretation. 
 
 
IV.  ADDITIONAL BEST PRACTICES FOR EVALUATION OF PROPOSED 
PROPRIETARY NAME 
 
In addition to the preliminary screening recommendations described in section III, we 
recommend that sponsors consider other important attributes described in this section during 
name development and before proceeding with further assessment to reduce the likelihood that a 
prescription drugs proprietary name will contribute to medication errors or other violations of 
the FD&C Act and its implementing regulations, either at the time of initial product launch or in 
the event of future product development.  FDA intends to evaluate each proposed proprietary 
name for these attributes and determine its acceptability on a case-specific basis. 
 
A.  Names That Include Reference to Product-Specific Attributes 
 
For flexibility in future product development and naming, FDA recommends that sponsors avoid 
incorporating product-specific attributes, such as manufacturing characteristics (e.g., 
NameLyophilized), dosage form (e.g.. Nametabs) or route of administration (e.g., 
Nameoral), as part of the proposed root proprietary name.  It is not uncommon for product-
specific attributes to change during a drugs life cycle with subsequent introductions of new 
dosing intervals, formulations, dosage forms, indications, and patient populations. If considering 
a proprietary name that includes or refers to product-specific attributes, sponsors should be 
mindful that future changes, such as changes in dosage form or route of administration, could 
render the root proprietary name inaccurate and thus unusable for future formulations.   
If references to product-specific attributes are included in the root proprietary name, FDA 
recommends that the name be evaluated to ensure that the product-specific attribute is consistent 
with the terminology used in the products labeling and does not pose risks for medication error. 
 
 
 
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  Contains Nonbinding Recommendations 
 
B.  Medical Abbreviations 
 
Sponsors are generally discouraged from incorporating symbols, dose designations, and medical 
abbreviations commonly used for prescription communication in their proposed proprietary 
name because their inclusion could inadvertently introduce a source of error. 
 
We recommend consulting The Joint Commissions Do Not Use list or the Institute for Safe 
Medication Practices (ISMP) List of Error-Prone Abbreviations, Symbols, and Dose 
Designations when considering the risk that a proposed proprietary name incorporating an 
abbreviation, symbol, or dose designation in a proposed proprietary name will be subject to 
misinterpretation.21,22 
 
When evaluating a proposed proprietary name that contains an element that is also an 
abbreviation, symbol, or dose designation, FDA recommends considering other factors such as 
placement and presentation that may influence interpretation of the element to make sure the way 
it is presented in the name is not error-prone.  As an example, po has been used historically as 
an abbreviation for oral route of administration in a medication order, typically appearing after 
the drug name.  Therefore, while the inclusion of letters po in the beginning or within the root 
proprietary name (e.g. Poname or Napome) is unlikely to be misconstrued as a medical 
abbreviation, and thus would not be expected to pose a risk for medication errors, if po is used 
in the ending of the root proprietary name or as a modifier (e.g. Name PO or Namepo), this 
would increase the likelihood of po being misconstrued as an abbreviation for the oral route of 
administration and thus create confusion if this is not the intended meaning. 
 
C.  Modifiers as Components of a Proprietary Name  
 
Some proprietary names are constructed of a root proprietary name modified by added words or 
components, which are referred to as modifiers.  The modifier portion of a proprietary name 
generally consists of one or more letters, symbols, numbers, and/or words, and appears at the 
beginning or end of the root proprietary name, typically set off by a space or hyphen.  Sponsors 
frequently propose a shared root proprietary name with various modifiers to distinguish among 
multiple products that contain at least one shared active ingredient. 
 
Inconsistencies in the use of modifiers and the absence of a standardized meaning for some 
modifiers that are meant to convey information about a product have been a source of confusion 
to end users.23,24,25  For example, sometimes modifiers are used to convey distinguishing product 
                                                 
21 The Joint Commissions Official Do Not Use List of Abbreviations, 2004, available at 
http://www.jointcommission.org/assets/1/18/Official_Do_Not_Use_List_6_111.PDF, last accessed 12/10/19   
22 The Institute for Safe Medication Practices (ISMP) List of Error-Prone Abbreviations, Symbols, and Dose 
Designations, 2017, Horsham (PA), available at http://www.ismp.org/tools/errorproneabbreviations.pdf, last 
accessed 12/10/19 
 
23 Pennsylvania Patient Safety Authority. Drug Name Suffix Confusion is a Common Source of Errors. 2004 
Dec;1(4):17-8 
 
24 Institute for Safe Medication Practices. ISMP Medication Safety Alert! 2003 Oct;(8)21 
25 Institute for Safe Medication Practices. ISMP Medication Safety Alert! 2003 Oct;(8)21 
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characteristics, such as Name ODT (an orally disintegrating tablet) or Name XR (an 
extended-release formulation).  Confusion stemming from the use of modifiers in proprietary 
names has led to medication errors, such as dispensing and administering wrong formulation, 
wrong dose, wrong strength, or wrong frequency of administration.  Medication errors have also 
occurred within the same product line if the distinguishing modifier is omitted or disregarded 
when a product is prescribed or dispensed. 
 
To reduce such risks, FDA encourages sponsors that choose to use modifiers to select, whenever 
possible, an existing modifier with an established meaning that has not been a source of 
confusion (see Appendix A for examples of modifiers that, when intended to express the 
accompanying meaning, have not been a source of confusion). 
 
The following considerations are intended to help sponsors with this assessment: 
 
1.  General Considerations When Developing a Proprietary Name That May Include a 
Modifier 
 
  Do you currently market one or more products under the proposed root 
proprietary name? 
   
o  Proprietary names for prescription products that involve the use of family trade 
names are evaluated on a case-by-case basis.  Each request for review of a 
proposed proprietary name that includes a family trade name will be evaluated to 
consider whether the: 
  
i.  Products share at least one active ingredient or active moiety 
 
ii.  Products are differentiated by labeling (carton and container) 
 
iii.  Modifier conveys accurate information about the product 
 
iv.  Modifier effectively differentiates the product from other products in 
the product line 
 
In some cases, this naming practice has posed problems when the same root name 
is used for multiple products without modifiers that adequately differentiate the 
products.26    The types of errors that have resulted from family trade name 
confusion include, for example, the use of the product for the wrong indication, 
the administration of an unnecessary active ingredient, and the use of a product in 
the wrong patient population. 
 
  Does the product have a characteristic (e.g., extended-release formulation) that is 
typically described by a modifier for other products that share that same 
characteristic? 
                                                 
26 Institute for Safe Medication Practices, 2004, Safety Briefs: Caution: Dulcolax brand name extensions, ISMP Med 
Saf Alert Acute Care, 9(7):1-2. 
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In certain instances, a modifier associated with specific characteristics (such as XR 
for extended-release formulations or ODT for orally disintegrating tablets) may be 
beneficial even if no product with these characteristics is marketed under the same 
root proprietary name.  For example, there may be other immediate-release 
formulations containing the active ingredient that are marketed under different root 
names.  In these cases, the addition of a modifier may provide incremental benefit 
in signaling the correct route or manner of administration. 
 
  Where will the modifier be placed in relation to the root proprietary name?  Are 
there any conventions for the modifier placement that are used within the particular 
drug product class? 
 
o  Although modifiers are usually placed at the end of the root name, there may be 
certain instances in which the modifier is placed at the beginning of the root 
name.  For example, proprietary names of oral contraceptives often include 
modifiers before the root name, such as Lo Simpesse, Tri-Linyah.  In these cases, 
the placement of modifiers is consistent with the established proprietary naming 
practices for the class. 
 
  What is the risk of medication error resulting from omitting a modifier or 
alternatively including a modifier that is misinterpreted as a medical term, 
abbreviation, or other medical product name?27 
 
o  In some instances, analysis of the risk of errors related to the use of a modifier 
may suggest that the use of an entirely distinct proprietary name for a product is 
safer than the use of the same root proprietary name with a modifier (see section 
IV.D for a detailed discussion of the risks).  Such circumstances may arise when a 
product under development will have significantly different indications and usage, 
patient populations, dosages, safety profiles, or routes of administration from the 
marketed product. 
 
2.  Additional and Special Considerations Related to Certain Types of Modifiers  
 
In addition to the above general considerations that are applicable to all modifier 
assessments, there are certain types of modifiers that are commonly used and warrant 
special considerations as described below. 
 
a.  Descriptive modifiers 
 
Some modifiers are composed of letters or words that are meant to convey information 
about the products composition or use, and FDA refers to these as descriptive modifiers.  
Examples would include the abbreviations in Appendix A and accompanying words to 
                                                 
27 See section VI for consideration on how to identify names with potential similarity to the proposed modifier. 
 
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describe some aspect of the product (e.g., indication, formulation, patient population).  
For example, the modifier viscous in Photrexa Viscous describes the formulation. 
 
Potential for medication errors arises when descriptive modifiers are ambiguous, 
misleading, or subject to misinterpretation.  A primary factor in evaluating a modifier 
associated with a proprietary name is whether the modifiers intended meaning is 
supported by the labeling and whether it is understood by the end user.  Some factors to 
consider are: 
 
  If the modifier is intended to convey information about a pertinent characteristic of 
the product, does it accurately describe that characteristic? 
 
  What is the modifiers intended meaning?  Are there data from a label comprehension 
study (or similar study) or data available from published literature to support that 
health care professionals and consumers understand the intended meaning? 
 
  What is the risk if end users misinterpret the modifiers intended meaning?  What is 
the impact of a medication error if an end user confuses the modifier with some other 
element of a prescription or order (such as frequency, strength, route of 
administration)?  Alternatively, what is the risk if the modifier is omitted? 
 
  Is the proposed modifier currently used in the marketplace?  We recommend 
checking the ISMPs current List of Products with Drug Name Suffixes and other 
drug information references to determine whether the proposed modifier is already 
used in the marketplace and whether it has been used consistently with a commonly 
recognized meaning.28  If an existing modifier with the same intended meaning is in 
the marketplace and familiar to and understood by end users without error, FDA 
recommends adopting that existing modifier.  When deciding whether to use a 
different modifier instead of an existing modifier with the same intended meaning, 
consider whether the proposed modifier conveys the intended meaning as clearly as, 
or more clearly than, the existing modifier. 
 
b.   Combination drug-device product modifiers 
   
Some proprietary name modifiers represent the delivery device component of a 
combination drug-device product.  When the device component name is presented 
contiguously with the drug component name and is part of the proposed proprietary 
name, such modifiers are reviewed as part of the Center for Drug Evaluation and 
Researchs (CDERs) or the Center for Biologics Evaluation and Researchs (CBERs) 
proprietary name evaluation.  Conventionally, for drug-device products with a drug 
primary mode of action, the proprietary name of the drug component precedes the 
proprietary name or modifier of the device component.  For example, a product 
integrating a drug and a disposable injector device might use a name such as Drugname 
Pen, composed of the root proprietary name for the drug component followed by the 
                                                 
28 ISMPs List of Products With Drug Name Suffixes internet, 2010. Horsham (PA): Institute for Safe Medication 
Practices, available at http://www.ismp.org/Tools/drugnamesuffixes.pdf, last accessed 12/10/19 
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  Contains Nonbinding Recommendations 
 
modifier pen indicating the presence of the device component.  Generally, modifiers 
used with combination products that represent a device component are either (a) a 
descriptive modifier that conveys the type of device such as Pen, Prefilled Syringe, 
or Inhaler or (b) a sponsor-coined modifier, such as SOLOSTAR or Diskus. 
 
A descriptive modifier may be suitable to use across different combination products 
provided it accurately describes the combination product.  Such descriptive modifiers 
tend to convey in a general manner the category or type of device component (e.g., 
Pen, Prefilled Syringe, Inhaler).  Although the device constituent part across 
various combination products that use the same descriptive modifier may operate 
differently and may contain different drugs, if the descriptive modifier is well understood 
as describing a general category or type of device component to end users, FDA would 
generally not have concern for confusion or errors. 
 
Conversely, a sponsor-coined modifier may be well understood to represent a specific 
device platform or technology.  For these types of modifiers, sponsors may wish to use 
the same modifier for a specific device platform across a number of drug-device 
combination products, each containing different active moieties, to help prescribers and 
end users understand the similar nature of the products.  In such situations, FDA 
generally will not object to this naming strategy if the drug component portions of the 
proprietary names are adequately distinguishable and any differences in the operation of 
the device across products is minor and otherwise not expected to result in errors.29 
 
A final consideration for device modifiers used with drug-device combination products 
relates to the introduction of a new device component that operates similarly, but not 
identically, to a previously marketed device component that delivered the same drug 
product.  For example, if a sponsor is developing a drug-device combination product that 
includes a new disposable injector device which introduces differences in critical tasks 
that are likely to result in errors among prior users compared to an earlier marketed 
device,30 a distinct modifier should be used to represent the new combination product in 
order to communicate to prescribers and patients that the new combination product 
operates differently from the earlier marketed combination product. 
 
c.  Use of numbers and symbols in modifiers 
 
FDA generally recommends sponsors avoid the use of numbers within a proprietary 
name.  Both Roman and Arabic numbers have been mistaken for the strength, quantity, 
                                                 
29 It is likely that FDA would have concern with the use of a single sponsor-coined modifier across combination 
products that do not operate similarly because it may mislead users and potentially lead to errors when administering 
the product. 
30 Critical tasks are those tasks that users must perform to safely and correctly use the product. 
 
13 
  Contains Nonbinding Recommendations 
 
duration, or controlled substance class of prescription drug products.31,32  For example, 
when a drug order or prescription is written for a drug product with a proprietary name 
that has the number 3 (to represent product strength) as part of its name, this might be 
misinterpreted to mean that three tablets are to be dispensed or that the product should be 
used for only 3 days.  FDA also generally recommends against using symbols (e.g., + 
or &) as part of proprietary names because symbols can be misinterpreted, misread, or 
confused (e.g., + could be read as 4).33  Therefore, as a best practice, FDA 
recommends using words rather than symbols. 
 
There are a few classes of drugs, however, for which there has been a historical practice 
of using a slash (/) or hyphen (-), or of using numbers as modifiers, resulting in 
established proprietary naming conventions for that class of drugs.  In these cases, FDA 
does not generally expect to object to proprietary names that include use of these 
elements that are consistent with the established practice for the class.  For example, the 
proprietary names of oral contraceptives may include the use of a slash or hyphen (Tri-
linyah, Junel 1/20) or vaccines may include the valency (Myvaccine 10). There may be a 
few instances where the use of numbers as modifiers minimizes the risk of errors and 
promotes appropriate use of the products by conveying information to end users.  For 
example, the proprietary names of oral contraceptives often include numerical modifiers 
to help differentiate among various strengths of the products.  Similarly, the proprietary 
names of insulin mixtures may use numerical modifiers to represent the proportion of 
each type of insulin in the mixture. 
 
D.  Dual Proprietary Names  
 
In certain cases, a modifier may not effectively convey a characteristic of the proposed product 
or reliably differentiate the proposed product from other products that contain the identical active 
moiety or ingredient(s).  Such circumstances may arise when a product under development will 
have significantly different indications and usage, patient populations, dosages, safety profiles, 
or routes of administration from the marketed product.  For example, two products may be 
administered using different routes of administration, or have differing doses, which may present 
a risk of medication errors to a population taking the product for a second indication.  In these 
unique instances, the use of two different proprietary names (also referred to as dual proprietary 
name) may be a safer naming approach.  However, sponsors should also consider the risks 
associated with this naming strategy.  For example, practitioners may be unaware that two 
products with different proprietary names prescribed for concomitant use contain the same active 
ingredient.  This could lead to overdose or dose-related adverse events.  Another risk may be if a 
drug-drug interaction is not noted because the health care professional and patient are unaware 
that a product sold under one proprietary name contains the same active ingredient as another 
                                                 
31 Institute for Safe Medication Practices. Misidentification of alphanumeric characters. ISMP Medication Safety 
Alert! Community/Ambulatory Care Edition. 2014 Jun; (19)11.  
https://www.ismp.org/resources/misidentification-alphanumeric-symbols, accessed 1/13/20. 
 
32 Institute for Safe Medication Practices. ISMP Medication Safety Alert! 2002 Jun; (7)13. 
33 ISMPs List of Error-Prone Abbreviations, 2010, Symbols, and Dose Designations. Horsham (PA): Institute for 
Safe Medication Practices, available at: http://www.ismp.org/tools/errorproneabbreviations.pdf, last accessed 
12/10/19 
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  Contains Nonbinding Recommendations 
 
product with a different proprietary name.  Sponsors should assess the safest naming convention 
for their situation and develop labeling and other measures to mitigate the risks associated with 
dual proprietary names.  FDA will evaluate these proposals on a case-specific basis along with 
any associated labeling that might address these potential risks. 
 
E.  Proprietary Names of Drug Products Marketed Outside the United States 
 
Medication errors resulting in dispensing and administering the wrong drug can occur when a 
proprietary name for a product marketed in the United States is identical, or nearly identical in 
spelling and pronunciation, to the proprietary name of a foreign product containing an entirely 
different active ingredient marketed only in a foreign country.  As seen in the example reported 
by ISMP, a medication error occurred when a patient took digoxin instead of the intended 
diltiazem product, both of which were marketed under the same proprietary name, Dilacor, in 
different countries.34  For this reason, as a best practice, FDA recommends against proposing a 
proprietary name that is identical or nearly identical to that of a marketed foreign product that 
contains an entirely different active ingredient, even if the proposed product will be marketed 
only in the United States (and even if the foreign product is not marketed in the United States). 
 
F.  Incorporation of the Sponsors Name  
 
FDA recommends that sponsors avoid proposed proprietary names that incorporate the sponsors 
name, or some part of the sponsors name, across multiple products (e.g., ABCName1, 
ABCName2, ABCName3).  This practice results in creating multiple similar proprietary 
names, increasing the risk of confusion among the products.  The practice could pose safety risks 
when products are stored alphabetically in distributor or pharmacy locations or when products 
are ordered from alphabetized lists. 
 
 
V.  FURTHER BEST PRACTICES FOR REVIEW, INCLUDING FOR 
 
MISBRANDING AND OTHER LEGAL CONCERNS 
 
Although this guidance focuses primarily on aspects of proprietary names that can contribute to 
medication error, as a best practice, sponsors should avoid using a proprietary name that could 
contribute to any violation of the FD&C Act.  For example, among other things, the FD&C Act 
provides that a drug is misbranded if its labeling is false or misleading in any particular (section 
502(a)).   
 
A proprietary name, which appears in labeling, could result in such misbranding if it is false or 
misleading, such as by making misrepresentations with respect to safety or efficacy.  For 
instance, a fanciful proprietary name may misbrand a product by suggesting that it has some 
unique effectiveness or composition when it is actually a common substance, the limitations of 
which are readily recognized when the product is listed by its established name (see 
	201.10(c)(3)).  For example, a proposed proprietary name that contains cure or that sounds like 
cure for a drug that treats the symptoms associated with a chronic disease would be concerning.  
                                                 
34 Institute for Safe Medication Practices, 2005, Safety briefs: Same name, different drug, ISMP Med Saf Alert 
Acute Care, 10(1):2 
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  Contains Nonbinding Recommendations 
 
The word cure is defined as something (such as a drug or medical treatment) that stops a 
disease and makes someone healthy again or something that ends a problem or improves a bad 
situation. 35  Therefore, if a proposed proprietary name for a chronic disease contains or sounds 
like cure, it would overstate the clinical benefit by misleadingly implying that the product can 
cure the chronic condition.  As another example, a drug is a new drug if it is not generally 
recognized as safe and effective (GRASE) for use under the conditions prescribed, 
recommended, or suggested in its labeling (section 201(p) of the FD&C Act), and the 
introduction of a new drug into interstate commerce without an approved application is 
prohibited (sections 301(d) and 505(a) of the FD&C Act; see also section 351 of the PHS Act).  
If the proprietary name of a drug suggests that it be used under conditions for which it is not 
GRASE and for which it does not have an approved new drug application (NDA) or biologics 
license application (BLA), distributing that drug with labeling bearing that proprietary name 
would violate the FD&C Act. 
 
In determining whether a name is misleading, common morphological and semantic associations 
are considered along with phonesthemes (the sound of the name) and phonosemantics (meaning 
conveyed by the sound of the word) of the name.36  Research has shown that linguistic 
characteristics can influence the way people perceive a product, particularly when it is new and 
unfamiliar as is the case with newly proposed proprietary names.37   
 
If a sponsor chooses to review for concerns other than those likely to contribute to medication 
errors, FDA recommends such a review be performed independent from a medication error 
review to minimize bias in either review.  The review should focus on identifying names that 
overstate product efficacy or safety, expand product indications, suggest superiority without 
substantiation, or are of a fanciful nature that misleadingly implies unique effectiveness or 
composition.  The analysis of sound empirical data, if available, should be given prominence in 
evaluating proposed proprietary names. 
 
One possible study methodology and some sample questions are outlined in Appendix B.  These 
sample questions are designed to guide sponsors in the development of outcome measures in 
their studies but are not intended to be an exhaustive list.  Sponsors are encouraged, but not 
required, to seek advisory comments from the Agency on their proposed study methodology, 
questionnaire, and analysis plan before collecting data. 
                                                 
35 Cure, Merriam-Webster.com (available at https://www.merriam-webster.com/dictionary/cure; accessed 
April 3, 2019). 
36 Bergen, B.K., 2004. The psychological reality of phonaesthemes, Language, 80:290-311. 
37Lowrey, TM, LJ Shrum, and TM Dubitsky, 2003, The relation between brand name linguistic characteristics and 
brand name memory, Journal of Advertising, 32:7-17. See also Keller, KL, SE Heckler, and MJ Houston, 1998, The 
effects of brand name suggestiveness on advertising recall, Journal of Marketing, 62:48-57.  These researchers, for 
example, conducted an experiment to investigate whether names that were suggestive of a particular characteristic of 
the product increased the recall and therefore the success of the communication.  They found that participants better 
recalled suggestive names for characteristics relevant to the product (e.g., a televisions picture quality; 
PicturePerfect) than those that were not suggestive (e.g., Emporium).  Other researchers have found that even parts 
of words or phonemes can influence perceptions and consumer judgments about unfamiliar names (Klink, RR, 2000, 
Creating brand names with meaning: The use of sound symbolism, Marketing Letters, 11:5-20; Yorkston, E and G 
Menon, 2004, A sound idea: Phonetic effects of brand names on consumer judgments, Journal of Consumer 
Research, 31:43-51). 
. 
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  Contains Nonbinding Recommendations 
 
 
VI.   RECOMMENDED METHODS FOR EVALUATING RISKS OF MEDICATION 
ERROR POSED BY SIMILARITY OF A PROPOSED PROPRIETARY NAME 
TO OTHER NAMES 
 
FDAs review of proprietary names focuses on avoiding end user error.  When evaluating a 
proposed proprietary name, FDA considers many potential sources for error, including phonetic, 
spelling, and orthographic similarities, as well as other sources of error identified elsewhere in 
this guidance. 
 
Specific methods that FDA uses to evaluate proposed proprietary names, as well as methods that 
FDA recommends sponsors use before submitting a proposed proprietary name for FDA review, 
are described below.  The descriptions include methods for identifying existing proprietary 
names or established names that could be confused with a sponsors proposed name, as well as 
methods for assessing the likelihood and potential effects of name-related medication errors.  If a 
sponsor includes detailed study report(s) providing data from its own safety assessment(s) and 
shows that these data were generated using a methodology that is generally consistent with that 
described in this guidance, FDA intends to use these data to help evaluate the risk that the 
proposed proprietary name would contribute to medication errors.  Sponsors are encouraged to 
conduct each of the types of assessments described below, but FDA considers what is submitted 
on its individual merits, regardless of whether the assessment includes every type of testing 
described below.38 
A.  Name Simulation Studies 
 
Name simulation studies conducted by FDA test how health care professionals employed by 
FDA respond to the proposed names.  The studies we conduct are limited in scope because they 
involve only FDA staff.  Although the sample size in FDAs simulation studies is small, these 
studies can provide important qualitative data that can be used to identify the potential 
vulnerability of a proposed name to be misinterpreted. The likelihood of observing an error in a 
small study is low, so that when an error is observed in a small study, this suggests that there will 
be errors in actual use. However, small studies may not be sufficiently sensitive to reliably 
identify all risks associated with a proposed proprietary name; the absence of observed errors in 
small studies is not conclusive evidence that a proposed name will not be confused with another 
                                                 
38 Because sponsors do not have access to non-public information on pending proposed proprietary names, FDA 
generally intends to use the methods described in this guidance to generate data to supplement any safety 
assessments provided by sponsors using the methods described in section VI to evaluate the proposed proprietary 
name for its potential to be confused with any non-public pending proposed proprietary names.  FDA may use the 
data identified from this supplementary evaluation of pending proposed name to determine if there are two or more 
proprietary names under review that could result in medication errors caused by potential confusion with each other, 
In these instances, FDA will notify both applicants of the conflict. 
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  Contains Nonbinding Recommendations 
 
drug products proprietary name. For these reasons, FDA believes it would be useful for 
sponsors to conduct more comprehensive simulation studies. 
 
Appendix C outlines elements that are recommended for consideration if sponsors choose to 
conduct simulation studies. 
B.  Obtain Medication Error Data for Names That Are Already Associated With 
Marketed Products 
 
Case reports of medication errors related to proprietary names that are already associated with 
marketed products can help inform the analysis of a proposed proprietary name.  FDA monitors 
medication error reports to identify cases of name confusion with the goal of identifying relevant 
information about the causes of problems and failures that lead to medication error, and the 
Agency applies any relevant information to the evaluation of a proposed proprietary name.  FDA 
recommends that sponsors obtain medication error report information from their internal safety 
databases, publicly available VAERS (Vaccine Adverse Event Reporting System) or FAERS 
(FDA Adverse Event Reporting System) data,39 published literature, and resources available 
through patient safety organizations such as ISMP. 
 
In some cases, there is marketing experience with the proposed proprietary name outside of the 
United States.  In these cases, if a sponsor obtains medication error information related to the 
products established, proper, and/or proposed proprietary name that may be relevant to using the 
proposed proprietary name in the United States, FDA recommends this information be provided 
to FDA in the proprietary name submission.40 
C.  Computational Method To Identify Names With Potential Orthographic, Spelling, 
and Phonetic Similarities 
 
FDA evaluates the orthographic and phonetic similarity of a proposed proprietary name to other 
names by using the POCA software.41  FDA enters the proposed proprietary name into FDAs 
POCA system and queries the proposed proprietary name against names in drug reference 
databases (e.g., Drugs@FDA and RxNorm).  Sponsors may include a POCA evaluation with 
their proprietary name submissions; when included, FDA will use data from a sponsors POCA 
evaluation to help evaluate the proposed proprietary name, provided that the methodology 
employed to generate the data is generally consistent with the methods described below. 
 
                                                 
39 Available at 
https://www.fda.gov/drugs/guidancecomplianceregulatoryinformation/surveillance/adversedrugeffects. 
40 See 21 CFR 312.32(b). Sponsors are required to promptly review all information relevant to the safety of the drug 
product obtained or otherwise received from any source, foreign or domestic, including information derived from any 
clinical or epidemiological investigations, reports in the scientific literature, unpublished scientific papers, reports from 
foreign regulatory authorities, and reports of foreign commercial marketing experience for drugs that are not marketed 
in the United States. 
41 On February 17, 2009 (74 FR 7450), FDA announced the availability of the source code and supporting technical 
documentation for POCA software program royalty-free to the public. 
 
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  Contains Nonbinding Recommendations 
 
Regardless of whether a sponsor submits data from POCA for FDA to consider in its review, 
FDA will independently conduct a review using POCA to compare the proposed proprietary 
name to other proposed proprietary names submitted to the Agency for products not yet 
approved.  Such names are often confidential; therefore, it is possible that FDA may identify 
conflicts with the names of pending products that are not publicly known to other sponsors 
proposing proprietary names.42 
 
FDA recommends that sponsors screen their proposed proprietary names by conducting 
orthographic and phonetic searches using the POCA system developed by FDA.  We recommend 
that you use POCA to search databases that encompass many drug products, such as 
Drugs@FDA, and another database that captures a reasonable representation of nonprescription 
drugs (e.g., RxNorm). 
 
The threshold FDA uses to conduct the orthographic and phonetic searches is set at a combined 
score of 55%, based on the validation work done on the POCA algorithms.  Based on our 
postmarketing experience, the combined measure of similarity has been positively correlated to 
errors involving name confusion. 
 
When using POCA, if the proposed name contains a modifier, first enter the root proprietary 
name without the modifier and group the names as described below.  Then repeat this process 
using the root name and modifier. 43 
 
The POCA search will provide three data sets: (1) COMBINED orthographic and phonetic 
matches, (2) phonetic matches, and (3) orthographic matches.  Sponsors should review the 
COMBINED orthographic and phonetic matches and group the name pairs into one of the 
following three categories: 
 
  Highly Similar Name Pair: combined match percentage score 70% 
  Moderately Similar Name Pair: combined match percentage score 55% to  69% 
  Low Similarity Name Pair: combined match percentage score 54% 
 
As a general principle, the higher the percentage assigned by POCA, the greater similarity the 
proposed proprietary name has to the name identified by POCA.  Research has shown that names 
involved in postmarketing medication errors because of prescribing or dispensing the wrong drug 
have a higher degree of similarity than drug names that were not involved in these types of 
                                                 
42 Proposed names may be associated with drug products related to investigational new drug applications, NDAs, 
biologics license applications, or abbreviated new drug applications. In those rare instances when a conflict is 
identified with the proposed proprietary names of two pending drug applications, FDA will notify both Applicants 
of the conflict in accordance with the Manual of Policies and Procedures: Procedures for Sharing Non-public 
Information on Pending Proposed Proprietary Names, which is available at:   
http://www.fda.gov/downloads/AboutFDA/CentersOffices/OfficeofMedicalProductsandTobacco/CDER/ManualofP
oliciesProcedures/UCM521551.pdf.  
43 FDA only searches the combined root name and modifier in POCA if the total length of the name (root name + 
modifier) is 10 letters or fewer. For modifiers located prior to the root name, e.g. Lo Ovral, Tri Sprintec, the entire 
name is searched in POCA. 
 
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  Contains Nonbinding Recommendations 
 
medication errors.44  This research is corroborated by our postmarket surveillance of medication 
errors and root cause analyses.  Therefore, based on this research and postmarketing surveillance, 
we expect names with high similarity scores to be more likely to result in confusion. 
D.  Safety Determination of Names With Potential Orthographic, Spelling, and 
Phonetic Similarities 
 
The acceptability of the proposed proprietary name from a look-alike and sound-alike 
perspective is reviewed using the criteria outlined in checklists in Appendices D, E, and F, which 
correspond to each of the three categories (Highly Similar Name Pair, Moderately Similar Name 
Pair, and Low Similarity Name Pair) described in section VI.C.  The intent of these checklists is 
to increase the transparency and predictability of the safety determination of whether a proposed 
proprietary name is vulnerable to confusion from a look-alike or sound-alike perspective.  Each 
bullet below corresponds to the name similarity category described in section VI.C. and cross-
references the respective Appendix that addresses criteria that FDA uses to determine whether 
and to what extent a name presents a safety concern. 
 
  For highly similar name pairs, based on postmarketing experience, we know that 
differences in product characteristics, including differences such as strength and dose, 
often cannot mitigate the risk of a medication error.  Therefore, proprietary name 
pairs that are highly similar (i.e. have a combined score of  70%) are at greater risk 
for a look-alike and sound-alike confusion,45 which is an area of concern for FDA 
(see Appendix D). 
 
  Moderately similar name pairs should be further evaluated to identify the presence of 
attributes that are known to cause name confusion. 
 
o  Name attributes:  The first part of the drug name plays a significant role in 
contributing to name confusion.  Additionally, drug name pairs that start with the 
same first letter and contain a shared letter string of at least 3 letters in both names 
are a major contributing factor in the confusion of drug names.46  We evaluate all 
moderately similar name pairs retrieved from POCA to identify the above 
attributes.  These name pairs are further evaluated to identify overlapping or 
similar strengths or doses. 
 
o  Product attributes:  Moderately similar name pairs of products that have 
overlapping or similar strengths or doses represent an area of concern to FDA.  
The dose and strength information is often located in close proximity to the drug 
name on prescriptions and medication orders, and that information can be an 
important factor that either increases or decreases the potential for confusion 
                                                 
44 Lambert, BL, S-J Lin, K-Y Chang et al., 1999, Similarity as a risk factor in drug-name confusion errors: The look-
alike (orthographic) and sound-alike (phonetic) model, Medical Care, 37(12):12141225. 
45 We have also identified similar concerns with individual orthographic or phonetic POCA scores of   70%.  
46 Shah, MB, L Merchant, IZ Chan et al., Characteristics that may help in the identification of potentially confusing 
proprietary drug names, Therapeutic Innovation and Regulatory Science, 51(2): September 2016. 
 
20 
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between similarly drug-named pairs.  The ability of other product characteristics 
to mitigate confusion (e.g., route of administration, frequency of administration, 
dosage form) may be limited when the strength or dose overlaps.  FDA will 
review such name pairs further to determine whether sufficient differences exist 
to prevent confusion (see Appendix E). 
 
  Name pairs with low similarity are generally acceptable (see Appendix F) unless 
there are data to suggest that the name might be vulnerable to confusion (e.g., name 
simulation study suggests that the proposed proprietary name is likely to be 
misinterpreted as that of a marketed product).  In these instances, we would reassign a 
low similarity name to the moderately similarity category and review accordingly 
(see Appendix E). 
 
In conclusion, FDAs recommendations in this guidance are intended to help sponsors avoid 
choosing a proprietary name that is likely to contribute to medication errors or otherwise 
contribute to violations of the FD&C Act.  In evaluating a proposed proprietary name, FDA 
considers the information and analyses about the proposed proprietary name described in this 
guidance, along with any additional name-related information submitted by the sponsor. 
Assessments of a proprietary name are necessarily fact-specific, and therefore, FDAs 
determinations are made on a case-by-case basis, considering the totality of the information. 
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GLOSSARY 
1 
2   
3  The following terms are described only to assist in understanding how they are used in this 
4  guidance, and are not intended for use outside the context of this guidance: 
5   
6  Active ingredient:  An active ingredient is any component that is intended to furnish 
7  pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or 
8  prevention of disease, or to affect the structure or any function of the body of man or other 
9  animals. The term includes those components that may undergo chemical change in the 
10  manufacture of the drug product and be present in the drug product in a modified form intended 
11  to furnish the specified activity or effect.  See also 21 CFR 314.3(b).  
12   
13  Active moiety:  An active moiety means the molecule or ion, excluding those appended portions 
14  of the molecule that cause the drug to be an ester, salt (including a salt with hydrogen or 
15  coordination bonds), or other noncovalent derivative (such as a complex, chelate, or clathrate) of 
16  the molecule, responsible for the physiological or pharmacological action of the drug substance.  
17  See also 21 CFR 314.3(b). 
18   
19  Adverse reaction:  An adverse reaction is an undesirable effect, reasonably associated with use 
20  of a drug, that may occur as part of the pharmacological action of the drug or may be 
21  unpredictable in its occurrence.  See also 21 CFR 201.57(c)(7). 
22   
23  Assimilation or deletion:  Assimilation is a change of a sound in speech so that it becomes 
24  identical with or similar to a neighboring sound.  An example of assimilation is when the \z\ 
25  assimilates to \sh\ in the phrase his shoe.  Deletion occurs when a sound is omitted in 
26  pronunciation.  Deletion usually occurs within the initial syllable of a word following at least one 
27  consonant and followed by a stressed syllable.  Examples of deletion would include garage to 
28  grage and surround to  sround.  Deletion and assimilation can occur together, and often do, as 
29  the assimilation of one feature of a neighboring sound will make that sound less phonologically 
30  necessary and make its deletion more probable. 
31   
32  Brand name extension:  FDA uses the term brand name extension to refer to a naming practice 
33  that uses a proprietary name that is already associated with one or more marketed drug 
34  products, with or without a modifier, for a product that does not share any active ingredient(s) or 
35  active moiety(ies) with the marketed product(s). 
36   
37  Container closure system:  A container closure system refers to the sum of packaging 
38  components that together contain and protect the dosage form.  This includes primary packaging 
39  components and secondary packaging components, if the latter are intended to provide added 
40  protection to the drug product.  A packaging system is equivalent to a container closure system. 
41   
42  End user:  The term end user includes, but is not limited to, the patient, patients caregiver, 
43  prescribing physician, nurse, pharmacist, pharmacy technician, and other individuals who are 
44  involved in routinely procuring, stocking, storing, prescribing, dispensing, and administering 
45  medications (e.g., medication technicians). 
46   
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47  Established name:  Section 502(e)(3) of the FD&C Act (21 U.S.C. 352(e)(3)) states that: 
48   
49  the term established name, with respect to a drug or ingredient thereof, means (A) the 
50  applicable official name designated pursuant to section 508, or (B) if there is no such 
51  name and such drug, or such ingredient, is an article recognized in an official 
52  compendium, then the official title thereof in such compendium, or (C) if neither clause 
53  (A) or clause (B) of this subparagraph applies, then the common or usual name, if any of 
54  such drug or such ingredient, except that where clause (B) of this subparagraph applies to 
55  an article recognized in the United States Pharmacopeia and in the Homeopathic 
56  Pharmacopoeia under different official titles, the official title used in the United States 
57  Pharmacopeia shall apply unless it is labeled and offered for sale as a homeopathic drug, 
58  in which case the official title used in the Homeopathic Pharmacopoeia shall apply. 
59  [emphasis added] 
60   
61  Family trade name:  A family trade name results from a naming practice involving the use of a 
62  shared proprietary name to market multiple products with a shared active ingredient, using a 
63  suffix or modifier, to distinguish the products from one another.  This practice is also referred to 
64  as family branding. 
65   
66  Infix:  An infix is a group of letters that appears in the middle of the proprietary name. 
67   
68  Label:  As defined in section 201(k) of the FD&C Act (21 U.S.C. 321(k)), the term label means 
69  a display of written, printed, or graphic matter upon the immediate container of any article.  If 
70  any word, statement, or other information is required by the FD&C Act to appear on the label, it 
71  must appear on the outside container or wrapper, if there is one, or be easily legible through the 
72  outside container or wrapper. 
73   
74  Labeling:  As defined in section 201(m) of the FD&C Act, the term labeling means all labels 
75  and other written, printed, or graphic matter (1) upon any article or any of its containers or 
76  wrappers, or (2) accompanying such article. 
77   
78  Medication error:  A medication error is any preventable event that may cause or lead 
79  to inappropriate medication use or medication-related patient harm while the medication 
80  is in the control of the healthcare professional, patient, or consumer.  Such events may be 
81  related to professional practice, health care products, procedures, and systems, including 
82  prescribing, order communication, product labeling, packaging, and nomenclature, 
83  compounding, dispensing, distribution, administration, education, monitoring, and use.47 
84   
85  Modifier:  A modifier is a portion of the proprietary name.  Some proprietary drug names are 
86  constructed of a root proprietary name and added word(s) or other components that are referred 
87  to as the modifier portion of the proprietary drug name.  The modifier portion of a proprietary 
88  drug name might be a letter, number, word, device name, or combination of letters, numbers, and 
89  words appearing at the beginning or end of a root proprietary name, typically set off by a space 
90  or hyphen. 
91   
                                                 
47 See also National Coordinating Council for Medication Error Reporting and Prevention, available at 
https://www.nccmerp.org/about-medication-errors), last accessed on May 19, 2020 
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92  Official compendium:  The term official compendium is defined in section 201(j) of the FD&C 
93  Act as the official United States Pharmacopeia, official Homeopathic Pharmacopoeia of the 
94  United States, official National Formulary, or any supplement to any of them. 
95   
96  Packaging:  A package or market package refers to the container closure system and labeling, 
97  associated components (e.g., dosing cups, droppers, spoons), and external packaging (e.g., 
98  cartons or shrink wrap).  A market package is the article provided to a pharmacist or retail 
99  customer upon purchase and does not include packaging used solely for shipping such articles. 
100   
101  Prefix:  A prefix is a group of letters that appears at the beginning of the proprietary name. 
102   
103  Proper name:  For biological products, the term proper name means the nonproprietary name 
104  designated by FDA in the license for a biological product licensed under the PHS Act.  See also 
105  21 CFR 600.3(k). 
106   
107  Proprietary name:  The proprietary name of a drug product is its brand name48  
108   
109  Root proprietary name:  Some proprietary names are constructed of multiple components. 
110  When a proprietary name contains a modifier as one of the components, the non-modifier portion 
111  of the proprietary name is referred to as the root proprietary name.  The root proprietary name 
112  may be shared by multiple products.  An example of a root proprietary name for a prescription 
113  drug product is Lantus in Lantus Solostar. 
114    
115  Serious adverse event:   A serious adverse event is defined as an event that does or has the 
116  potential to result in death, hospitalization, congenital abnormality, permanent disability, or 
117  could be life-threatening.  See also 21 CFR 314.80. 
118   
119  Suffix:  A suffix is a group of letters that appears at the end of the proprietary name. 
120   
121  Vowel reduction:  Vowel reduction is any of various changes in the acoustic quality of vowels, 
122  which are related to changes in stress, sonority, duration, loudness, articulation, or position in the 
123  word, and which are perceived as weakening.  It most often makes the vowels shorter as well. 
                                                 
48 Sometimes referred to as the products trade name 
 
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Databases and Other Resources 
124 
125   
126  In most cases, the computerized resources listed here are publicly available. 
127    
128  FDA Adverse Event Reporting System (FAERS) 
129   
130  FAERS is a database that contains adverse event reports and medication error reports submitted 
131  to FDA.  The database is designed to support FDAs postmarket safety surveillance program for 
132  drug and therapeutic biologic products.  The informatic structure of the FAERS database adheres 
133  to the international safety reporting guidance issued by the International Council for 
134  Harmonization.  Adverse events and medication errors are coded using terms in the Medical 
135  Dictionary for Regulatory Activities (MedDRA) terminology.  More information about FAERS 
136  can be found at https://www.fda.gov/drugs/surveillance/fda-adverse-event-reporting-system-
137  faers.  
138   
139  Vaccine Adverse Event Reporting System (VAERS)  
140   
141  VAERS is a postmarket vaccine safety surveillance program cosponsored by the Centers for 
142  Disease Control and Prevention (CDC) and FDA.  VAERS collects information about adverse 
143  events that occur after the administration of U.S. licensed vaccines.  The VAERS website 
144  provides a nationwide mechanism by which adverse events following immunization can be 
145  reported, analyzed, and made available to the public.  The VAERS website also provides a 
146  vehicle for disseminating vaccine safety-related information to parents or guardians, health care 
147  professionals, vaccine manufacturers, state vaccine programs, and other constituencies.  The 
148  majority of VAERS reports are received from vaccine manufacturers and health care 
149  professionals.  More information about VAERS can be found at https://vaers.hhs.gov/. 
150   
151  Phonetic and Orthographic Computer Analysis (POCA) 
152   
153  POCA is a system designed by FDA and is publicly available by requesting the system from 
154  FDA.49  POCA is an analytical tool designed to help identify drug and biologic names that are 
155  phonetically and orthographically similar to one another.  The Alignment of Phonetic Sequences 
156  (ALINE) algorithm is used to calculate the phonetic score.  The orthographic component of the 
157  current algorithm was revised in December 2016 to accommodate the changing trends in 
158  medication errors due to technological changes.  The revised new algorithm is designed to better 
159  capture the shift in the type of errors that are being reported due to using electronic prescribing.  
160  The algorithm has been revised to put more emphasis on similarity that occurs at the beginning 
161  of the word, especially the first three letters (bigram or trigram), and on exact letter matches.  
162  The algorithm continues to have emphasis on consecutive exact matches but also emphasizes 
163  where names share letters that are not consecutive.  Several new score metrics (i.e., sub-
164  algorithms) are combined in various ways to formulate the final score.50 
                                                 
49 Available at https://www.fda.gov/drugs/information-industry-drugs/phonetic-and-orthographic-computer-
analysis-poca-program.   
50 Modified Adaptive Algorithm: Modified the existing bi-gram matching algorithm to account for reverse confuse 
lookups. Initial Match: Check up to first n matching letters. This is to accommodate beginning letter(s) overlap. 
 
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165   
166  POCA search provides three data sets:  (1) combined orthographic and phonetic matches, (2) 
167  phonetic matches, and (3) orthographic matches.  The threshold FDA uses to conduct the 
168  orthographic and phonetic searches is set at a combined score of 55%, based on the validation 
169  work done on the POCA algorithms. 
170   
171  Drugs@FDA 
172   
173  Drugs@FDA, is an FDA website that contains most of the drug and therapeutic biological 
174  products approved in the United States since 1939.  The majority of labeling, approval letters, 
175  reviews, and other information are available for products approved from 1998 to the present.  
176  Drugs@FDA contains information about FDA-approved brand name and generic drugs; 
177  therapeutic biological products, prescription and over-the-counter human drugs; and 
178  discontinued drugs. See Drugs@FDA, available at 
179  https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm. 
180   
181  RxNorm 
182   
183  RxNorm is publicly available and contains the names of prescription and many OTC drugs 
184  available in the United States.  RxNorm includes generic and branded drug products and 
185  packaging configurations.  Radiopharmaceuticals, contrast media, food, dietary supplements, and 
186  medical devices, such as bandages and crutches, are not included in RxNorm (see RxNorm, 
187  available at http://www.nlm.nih.gov/research/umls/rxnorm/overview.html#). 
188   
189  USAN Stems 
190   
191  The USAN Council (tri-sponsored by the American Medical Association (AMA), the United 
192  States Pharmacopeial Convention, and the American Pharmacists Association) aims for global 
193  standardization and unification of drug nomenclature and related rules to ensure that drug 
194  information is communicated accurately and unambiguously.  The USAN Council works closely 
195  with the International Nonproprietary Name Programme of the World Health Organization, and 
196  various national nomenclature groups.  The website is publicly available, managed by the AMA, 
197  and contains lists of all the recognized USAN stems (available at https://www.ama-
198  assn.org/about/united-states-adopted-names/united-states-adopted-names-approved-stems). 
199   
200  Medical Abbreviations References 
201   
202  Various references on this topic are available.  These references contain commonly used medical 
203  abbreviations and their definitions. 
                                                 
Longest Common Subsequence: the longest group of letters from two words that are common between the two 
groups and in the same order in each group. Unigram Match: This metric gives priority to overlapping letters fixed 
in the same position. Longest Common Substring: This metric gives priority to drug names embedded within another 
drug name. 
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Appendix A:  Examples of Previously Used Modifiers and Their 
204 
Commonly Understood Meanings 
205 
206   
Modifiers  Meaning 
XR  Extended-release product 
ER  Extended-release product 
DS  Double strength 
LA  Long acting 
For example, dose card package or 
carton containing two or more 
Pak  drugs 
Depot  Depot injection 
ODT  Orally disintegrating tablets 
Used as a modifier before the root 
name in oral contraceptives to 
Lo  indicate low-dose estrogen 
Used as a modifier before the root 
name in oral contraceptives to 
indicate triphasic oral 
Tri  contraceptive 
Used to indicate ferrous 
Fe  component 
207 
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Appendix B:  Research Methodology for Conducting  
208 
Misbranding Review 
209 
210   
211  For sponsors that wish to submit data on a proposed proprietary name, FDA recommends an 
212  experimental method as part of the approach to determine whether a proposed proprietary name 
213  is misleading because this method enables interpretation of causal relationships between 
214  variables.  That is, by controlling all other experimental factors besides the drug name, 
215  researchers can be confident that the name itself caused particular responses.  Box 1 provides one 
216  possible approach for such an evaluation.  Other approaches may be appropriate.  The approach 
217  described in Box 1 should be especially helpful in gathering information about how a name 
218  influences attitudes and behaviors of a practicing health care professional.  If participants are 
219  only asked what they think about the proposed name, it will be difficult to determine how 
220  accurately their responses reflect their actual thoughts or likely behaviors, because participants 
221  may state what they think they should state, or what they think the investigators want to hear.  
222  Comparing the responses to the proposed name with responses to the neutral control name, 
223  however, could determine whether the proposed name influences these thoughts and intended 
224  behaviors. 
225   
226  a.  Design of Questions 
227   
228  A combination of open-ended and closed-ended questions, arranged from more general to more 
229  specific, should be used.  Questions should be designed to avoid leading questions, yea-saying 
230  and other forms of bias.1  Initial questions in the study should be asked before participants have 
231  any information about the product so that the answers will not be influenced by knowledge of 
232  product characteristics.  Subsequent questions would be asked after receiving indication 
233  information for the product but no other identifying information. Because investigational new 
234  drug (IND) studies form the basis of ultimate determinations about the efficacy and risk of a drug 
235  product seeking approval, specifics may not be known at the time the proprietary name is 
236  proposed and undergoing testing.  Therefore, there should be a measure of participant response 
237  when participants have only minimal information. 
238   
239   
240   
241  Box 1: Possible Evaluation Design 
242   
243   
244   
245   
246   
247   
248   
249   
250   
                                                 
1 For a brief discussion of questionnaire bias in label comprehension studies, see Morris, L.A., Lechter, K., 
Weintraub, M., et al., Comprehension testing for OTC drug labels: Goals, methods, target population, and testing 
environment. Journal of Public Policy and Marketing. 1998;17(1):86-96. 
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251   
252   
The FDA recommends as one possible approach  a crossover design in which 
253   
the proposed proprietary name is evaluated in the context of both a neutral 
254   
control name and an extreme control name. This involves splitting the study 
255   
participants into two groups, both of whom will evaluate the proposed 
256   
proprietary name but in a different order from each other. 
257   
258    Before testing the proposed proprietary name, two control names should be 
259   
established through pretesting: 
260   
261      A neutral control name that is pretested to ensure that it makes no 
262    representations at all (i.e., it is neutral from a promotional standpoint) 
263    should be established. 
264      An extreme control name that is pretested to ensure it makes clear 
265    misrepresentations should be established. 
266   
All the participants will respond first to questions about the neutral control 
267   
name, described above.  Next, half of the participants respond to the proposed 
268   
name and then to the extreme control name described above.  The other half of 
269   
the participants respond to the extreme control name first and then to the 
270   
proposed name. 
271   
272    The study questions used as outcome measures should cover perceptions 
273   
elicited by the proposed name that are of a promotional nature (e.g., product 
274   
safety, efficacy, indication, superiority), as well as questions designed to elicit 
275   
aspects of behavioral intent (e.g., likelihood to prescribe).  A comparison of 
276   
interest is participant responses to the proposed name compared with responses 
277   
to the neutral control name.  The extreme name serves as a positive control to 
278   
ensure that individuals can identify names that make representations about 
279   
efficacy, safety, or other promotional aspects. 
280   
281    The FDA suggests that the neutral and extreme names be fictitious in nature to 
282    control for participants prior experience and attitudes.  Existing names could 
283    be acceptable as neutral or extreme controls if they are pretested and shown to 
284    possess the desired experimental qualities outlined above. 
285   
Sponsors may choose to select different neutral and extreme control names for 
286   
each study, or they may choose to use the same neutral and extreme control 
287   
names for multiple studies.  Participants should be exposed to the neutral 
288   
control name only once across studies; that is, sponsors that choose to use the 
289   
same neutral name in more than one study should choose a new set of 
290   
participants for that study to ensure that participants have not previously 
291    responded to the neutral name. 
292   
293  Examples of questions include: 
294    You have just learned of a new product named DRUG X.  What, if anything, does the 
295  name DRUG X say or suggest to you about the product? (open-ended question) 
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296    Based on this name, which of these conditions do you think DRUG X treats? (please 
297  choose the best answer) (closed-ended question) 
298  -  Condition 1 
299  -  Condition 2 
300  -  Condition 3 
301  -  Condition 4 
302    Based on this name, how effective or ineffective would you say DRUG X is? 
303  -  Very effective 
304  -  Somewhat effective 
305  -  Somewhat ineffective 
306  -  Very ineffective 
307    Based on this name, how safe or unsafe would you say DRUG X is? 
308  -  Very safe 
309  -  Somewhat safe 
310  -  Somewhat unsafe 
311  -  Very unsafe 
312    Now you learn that product DRUG X is used to treat CONDITION Y.  What does this 
313  name mean to you in this context? 
314  Based on this name, how safe or unsafe would you say it is to use DRUG X to treat 
315  CONDITION Y? 
316  -  Very safe 
317  -  Somewhat safe 
318  -  Somewhat unsafe 
319  -  Very unsafe 
320  Based on this name, how effective or ineffective would you say DRUG X is to treat 
321  CONDITION Y? 
322  -  Very effective 
323  -  Somewhat effective 
324  -  Somewhat ineffective 
325  -  Very ineffective 
326    If DRUG X were available, how likely would you be to prescribe DRUG X for 
327  CONDITION Y?  
328  -  Not at all likely 
329  -  Somewhat likely 
330  -  Moderately likely 
331  -  Very likely 
332    On a scale from 1 to 5, where 1 equals Strongly Disagree and 5 equals Strongly Agree, 
333  please indicate your agreement or disagreement with the following statement: 
334  This name suggests superiority over other products with the same indication. 
335   
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336  b.  Sampling 
337   
338  These are general comments. A statistician should be consulted before making definitive 
339  determinations about sample size and sampling design.  The size of the study participant sample 
340  should be adequate to detect differences.  The sample should represent the relevant prescribing 
341  population and be generalizable to this population.  In addition, sponsors should consider testing 
342  a sample of consumers.  Although this group does not have prescribing authority, consumers 
343  should and do participate actively in treatment decisions.  The product name may play a role here 
344  through direct-to-consumer advertising. 
345   
346  c.  Submission to FDA 
347   
348  If submitting data on a proposed proprietary name, sponsors should submit to the appropriate 
349  center for evaluation of all research methodology used to support that proposed proprietary 
350  name.  This includes a description of participant demographics; the study methodology 
351  (protocol); the product profile provided to study participants; the complete study questionnaire, 
352  including any screening questions; the coding scheme used to analyze open-ended questions; 
353  complete study results (both positive and negative), including results of pretests; and any other 
354  information given to the study participants regarding the drug approval process (e.g., copies of 
355  FDA regulations given to study participants). 
	
356 
	 	
357 
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Appendix	C:		Research	Methodology	Considerations	for	
358 
Conducting	Name	Simulation	Studies	
359 
360   
361  Generally, name simulation studies test how subjects respond to a proposed proprietary name by 
362  asking them to use the name in use conditions that simulate the real world.  The more closely and 
363  fully the simulation approximates real-world use conditions, the more generalizable the results of 
364  the simulation testing.  Name simulation tasks should reflect the full range and variety of tasks 
365  involved in the prescribing, transcribing, dispensing, and administering of drugs.  Simulations 
366  should include common characteristics of real use, such as using ruled or unruled paper, 
367  prescription pads, computer order entry, and telephone orders to approximate written, oral, and 
368  electronic prescribing in the setting of care for the proposed product (e.g., inpatient and 
369  outpatient settings, long-term care).  Simulations should approximate the diversity of real-world 
370  prescribing conditions by varying factors such as background noise, handwriting samples, 
371  different ink colors, directions for use, and different voices/accents.  In addition, the simulation 
372  study should present the proprietary name with the corresponding product characteristics (e.g., 
373  strength, route, dosage, and frequency) that are likely to be used to communicate prescriptions 
374  and orders for the proposed product.  For example, when considering a product that is dosed on 
375  milligram/kilogram basis, consider using an average weight-based dose for the intended 
376  population in the simulation study. 
377   
378  a.  Study Design  
379   
380  A simulation study designed to detect close to a zero percent error rate with statistical 
381  significance would call for an extremely large sample size (e.g., a sample of ~26,000 to detect an 
382  error rate of 0.001 at the 0.05 significance level).2  FDA recognizes that a study of this 
383  magnitude is not realistic.  However, a well-designed parallel group observational study 
384  consisting of the participants described below can provide useful insight into how a proposed 
385  proprietary name might perform in real-world conditions.  In such a study, each group represents 
386  different prescribing scenarios based on all the potential prescribing conditions for the proposed 
387  product.  We recommend that actively practicing health care professionals, such as prescribers, 
388  medical transcribers, pharmacists, pharmacy technicians, or nurses, who administer the products 
389  in the proposed use conditions for the product be included in the study. 
390   
391  When performing simulation testing, both quantitative and qualitative data should be collected.  
392  Both types of data can be collected anywhere in the medication-use system.  For example, 
393  quantitative data might document how many times a participant interpreted a prescription 
394  correctly and how many times it was misinterpreted.  Qualitative data should include any 
395  concerns or problems the participants thought of or encountered while going through the process 
396  (for example, no error occurred but a participant felt that an error could have occurred in the 
397  situation).  For a name that was misinterpreted, data should include whether the name was 
398  misinterpreted as another drug name or whether there were trends in spelling misinterpretations 
399  for specific letters. 
400   
                                                 
2 This calculation was made to determine whether the error rate differs from 0.001 at a 0.05 significance level and 
80% power, assuming the medication error rate of the sample is 0.0005. 
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401  b.  Participants  
402   
403  All participants in name simulation studies should be actively practicing health care 
404  professionals, such as prescribers, medical transcribers, pharmacists, pharmacy technicians, or 
405  nurses, who administer the products in the proposed use conditions for the product.  Sponsors 
406  should take care to ensure that participants are representative of the full range of persons 
407  involved in a given scenario.  The study should simulate the full range of settings where the 
408  product could be used, such as community pharmacy, ambulatory care, hospital, or long-term 
409  care.  For example, if the product will be dispensed in an inpatient setting, the participants should 
410  include, but not be limited to, inpatient pharmacists, pharmacy technicians, ward clerks, and 
411  nurses.  When evaluating proprietary names for specialty drugs, sponsors should consider 
412  whether the specialty drug could be at risk for entering into broader health care contexts.  If so, 
413  sponsors should consider including primary care practitioners, pharmacists, pharmacy 
414  technicians, and nurses to probe which product names outside the specialty might cause error.  
415  These stakeholders will bring experience from different workflow and practice environments. 
416    
417  c.  Number of Scenarios 
418   
419  For an adequate descriptive assessment, sponsors should test an adequate number of scenarios to 
420  provide a concomitant benefit in accuracy and reliability of the study outcomes.  Scenarios may 
421  vary depending on the type of setting and should be appropriate for the product being tested.  
422  Participants involved in a name simulation study can participate in the testing of multiple 
423  proposed proprietary names.  However, to minimize bias, a name should be tested only once by 
424  the same participant in the written and spoken scenarios. 
425   
426  Each anticipated prescribing condition for the proposed product should be tested several times, 
427  considering all relevant modes of communication (such as spoken, written, computer order entry, 
428  computer selection, and selection of product from drop-down menu).  For example, for a product 
429  that is administered only intravenously in an inpatient setting, an outpatient simulation using a 
430  handwritten prescription might not be helpful.  A simulation for an orally administered product 
431  that could be dispensed in either inpatient or outpatient settings should contain all possible 
432  inpatient and outpatient scenarios.  When appropriate, these scenarios should be revised to 
433  reflect, as closely as possible, the likely health care setting(s) for using the product, including 
434  how the product will be prescribed, how the prescription will be transcribed, and how the 
435  product will be dispensed and administered.  
436   
437  Sponsors should consider embedding the test name in a list of two or three other proprietary 
438  names of marketed products in the simulated prescriptions, or consider using other simulated 
439  prescription formats that are designed to mimic actual use.  Spoken orders should include several 
440  scenarios with an unaided pronunciation and several scenarios with a pronunciation based on 
441  how the sponsor proposes to pronounce the name when marketed (for example, Kaletra is 
442  pronounced by some as Kuh-let-ra and the sponsors pronunciation is Kuh-lee-tra). 
443   
444  At the end of a simulation, each participant should be interviewed, preferably using nonleading 
445  scripted follow-up questions.  The participant responses should be recorded verbatim.  All 
446  qualitative data derived from follow-up questioning should be coded and analyzed.  The 
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447  verbatim responses might confirm or further describe a potential for confusion.  More 
448  importantly, responses might identify additional names of concern that were not identified 
449  through a manual database or computational searches.  The names identified from the simulation 
450  study should then be evaluated as outlined in section IV of this guidance to assess the likelihood 
451  of confusion with the proposed name. 
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Appendix D:  Highly Similar Name Pair Checklist
452   
453   
454  Highly Similar Name Pair Checklist (i.e., COMBINED Orthographic/Phonetic score is  70%) 
455   
Answer the questions in the checklist below.  Affirmative answers to some of these questions 
suggest that the pattern of orthographic or phonetic differences in the names may render the 
names less likely to confusion, provided that the pair do not share a common strength or dose. 
Orthographic Checklist  Phonetic Checklist 
  Do the names begin with    Do the names have 
Y/N  different first letters?   Y/N  different number of 
Note that even when names  syllables? 
  begin with different first letters, 
certain letters may be confused 
with each other when scripted. 
  Are the lengths of the    Do the names have 
Y/N  names dissimilar when  Y/N  different syllabic 
scripted or printed?  stresses? 
  FDA considers the length of     
names different if the names 
differ by two or more letters.   
This may be dependent on the 
position of the letters within the 
name and which letters are 
used. Some letters are more 
noticeable than others (e.g., 
m is a wide, noticeable 
letter). 
  Considering variations in    Do the syllables have 
Y/N  scripting of some letters  Y/N  different phonologic 
(such as z and f), is there a  processes, such as 
   
different number or  vowel reduction, 
placement of  assimilation, or 
upstroke/downstroke  deletion? 
letters present in the 
names?   
  Is there different number    Across a range of 
Y/N  or placement of cross- Y/N  dialects, are the names 
stroke or dotted letters  consistently 
   
present in the names?    pronounced 
differently?
  Do the infixes of the 
Y/N  name appear dissimilar     
when scripted?
  Do the suffixes of the 
Y/N  names appear dissimilar     
when scripted?
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Appendix E:  Moderately Similar Name Pair Checklist
456   
457   
458  Moderately Similar Name Pair Checklist (i.e., combined score is 55% to 69%) 
459   
Step 1   Review the DOSAGE AND ADMINISTRATION and HOW 
SUPPLIED/STORAGE AND HANDLING sections of the Prescribing 
Information to determine whether strengths and doses of the name pair overlap 
or are very similar.  Different strengths and doses for products whose names are 
moderately similar may decrease the risk of confusion between the moderately 
similar name pairs.  Name pairs that have overlapping or similar strengths or 
doses have a higher potential for confusion and should be evaluated further (see 
Step 2).  Because the strength or dose could be used to express an order or 
prescription for a particular drug product, overlap in one or both of these 
components would be reason for further evaluation. 
For single-strength products, also consider circumstances where the strength may 
be omitted. 
For any drug products comprised of more than one active ingredient, consider 
whether the strength or dose may be expressed using only one of the 
components. 
To determine whether the strengths or doses are similar to your proposed 
product, consider the following list of factors that may increase confusion: 
o  Alternative expressions of dose:  for example, 5 milliliters (mL) may 
be listed in the Prescribing Information, but the prescription may 
express the dose in metric units (e.g., 500 milligrams (mg)) or in non-
metric units (e.g., 1 teaspoon, 1 tablet/capsule).  Similarly, a strength 
or dose of 1,000 mg may be expressed, in practice, as 1 gram, or vice 
versa. 
o  Presence of trailing zeros or absence of leading zeros:  for example,  
10 mg (if written as 10.0 mg) is similar in appearance to 100 mg, 
which may potentiate confusion between a name pair with moderate 
similarity.  Additionally, 0.1 mg can be confused with 1 mg if written 
without a leading zero (.1 mg). 
o  Similar sounding doses:  for example, 15 mg is similar in sound to  
50 mg. 
460   
461     
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462   
Step 2  Answer the questions in the checklist below.  Affirmative answers to some of 
these questions suggest that the pattern of orthographic or phonetic differences in 
the names may reduce the likelihood of confusion for moderately similar names 
with overlapping or similar strengths or doses. 
Orthographic Checklist  Phonetic Checklist 
(Y/N to each question)  (Y/N to each question) 
  Do the names begin with    Do the names have different 
different first letters?  number of syllables? 
Note that even when names begin    Do the names have different 
with different first letters, certain 
syllabic stresses? 
letters may be confused with each 
other when scripted.    Do the syllables have different 
phonologic processes, such as 
  Are the lengths of the names 
vowel reduction, assimilation, 
dissimilar when scripted? 
or deletion? 
FDA considers the length of names 
different if the names differ by two    Across a range of dialects, are 
or more letters.  the names consistently 
pronounced differently? 
  Considering variations in 
scripting of some letters (such 
as z and f), is there a different 
number or placement of 
upstroke/downstroke letters 
present in the names? 
  Is there different number or 
placement of cross-stroke or 
dotted letters present in the 
names? 
  Do the infixes of the name 
appear dissimilar when 
scripted? 
  Do the suffixes of the names 
appear dissimilar when 
scripted? 
463 
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Appendix F:  Low Similarity Name Pairs
464   
465   
466  Low Similarity Name Pairs (i.e., combined score is 54%) 
467   
  Names with low similarity are generally acceptable unless there are data to 
suggest that the name might be vulnerable to confusion (e.g., prescription 
simulation study suggests that the name is likely to be misinterpreted as a 
marketed product).  In these instances, we would evaluate the name pair as  
moderate similarity and review according to the moderately similar name pair 
checklist (see Appendix E).  
468   
469   
470   
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