DEPARTMENT OF HEALTH AND HUMAN SERVICES 

OFFICE OF INSPECTOR GENERAL 

WASHINGTON, DC 20201 

JUN 30 2015 

TO: 	 Andrew M. Slavitt 

Acting Administrator 

Centers for Medicare & Medicaid Services 

FROM: Suzanne Murrin 

Deputy Inspeetor General 

for Rwluation and Inspections 

SUBJECT: 	 Memorandum Report: Part D Plans Generally Include Drugs Commonly 

Used by Dual Eligibles: 2015, OEI-05-15-00120 

This memorandum report fulfills the annual reporting mandate from the Patient 

Protection and Affordable Care Act (ACA) for 2015. The ACA requires that the Office 

of Inspector General (OIG) conduct a study ofthe extent to which formularies used by 

stand-alone prescription drug plans (PDPs) and Medicare Advantage prescription drug 

plans (MA-PDs) under Medicare Part D include drugs commonly used by full-benefit 

dual-eligible individuals (i.e., individuals who are eligible for both Medicare and full 

Medicaid benefits). 1 Pursuant to the ACA, OIG must annually issue a report, with 

recommendations as appropriate. This is the fifth report that OIG has produced to meet 

this mandate. For the relevant text ofthe ACA, see Appendix A. 

SUMMARY 

Pursuant to the Medicare Prescription Drug, Improvement, and Modernization Act of 

2003 (MMA), comprehensive prescription drug coverage under Medicare Part Dis 

available to all Medicare beneficiaries through PD Ps and MA-PDs (hereinafter referred 

to collectively as Part D plans).2 

For beneficiaries who are eligible for both Medicare and Medicaid (hereinafter referred to 

as dual eligibles), Medicare covers Part D plan premiums, deductibles, and other 

cost-sharing up to a determined premium benchmark that varies by region. If dual 

eligibles enroll in Part D plans with premiums higher than the regional benchmark, they 

are responsible for paying the premium amounts above that benchmark. 

1 ACA, P.L. No. 111-148 § 3313(a), 42 U.S.C. § 1395w-101 note. 2 MMA, P.L. No. 108-173 § 101, Social Security Act, § 1860D-l(a). 
 

 

 

 

 

 

 

 

Page 2 – Andrew M. Slavitt 

To control costs and ensure the safe use of drugs, Part D plans are allowed to establish 

formularies from which they may omit drugs from prescription coverage and are allowed 

to control drug utilization through utilization management tools.3 These tools include 

prior authorization, quantity limits, and step therapy.4 

The Centers for Medicare & Medicaid Services (CMS) annually reviews Part D plan 

formularies to ensure that they include a range of drugs in a broad distribution of 

therapeutic categories or classes. CMS also assesses the utilization management tools 

present in each formulary. 

For this memorandum report, we determined whether the 341 unique formularies used by 

the 3,152 Part D plans operating in 2015 cover the 200 drugs most commonly used by 

dual eligibles. We also determined the extent to which those commonly used drugs are 

subject to utilization management tools. 

Overall, we found that the rate of Part D plan formularies’ inclusion of the drugs 

commonly used by dual eligibles is high, with some variation. On average, Part D plan 

formularies include 95 percent of the commonly used drugs. In addition, 71 percent of 

the commonly used drugs are included by all Part D plan formularies. 

We also found that from 2014 to 2015, the proportion of unique drugs subject to 

utilization management tools remained relatively the same. On average, formularies 

applied utilization management tools to 29 percent of the unique drugs we reviewed in 

2015, compared to 28 percent of those we reviewed in 2014. 

The results of our analysis for 2015 are largely unchanged from OIG’s findings in 2011, 

2012, 2013, and 2014.5, 6, 7, 8 

3

 A formulary is a list of drugs covered by a Part D plan. Part D plans can exclude drugs from their 

formularies and can control utilization for formulary-included drugs within certain parameters. Social 

Security Act § 1860D-4(b) and (c).
 4

 Prior authorization—often required for very expensive drugs—requires that physicians obtain approval
 

from Part D plans to prescribe a specific drug. Quantity limits are intended to ensure that beneficiaries 

receive the proper dose and recommended duration of drug therapy. Step therapy is the practice of 

beginning drug therapy for a medical condition with the drug therapy that is the most cost-effective or 

safest and progressing if necessary to more costly or risky drug therapy. 

5

 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles, OEI-05-10-00390, 

April 2011. 

6

 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2012, 

OEI-05-12-00060, June 2012. 

7

 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2013, 

OEI-15-13-00090, June 2013. 

8

 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2014, 

OEI-05-14-00170, June 2014. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

 

 

Page 3 – Andrew M. Slavitt 

BACKGROUND 

The Medicare Prescription Drug Benefit 

Beginning in 2006, the MMA made comprehensive prescription drug coverage under 

Medicare Part D available to all Medicare beneficiaries.9 Medicare beneficiaries 

generally have the option to enroll in a PDP and receive all other Medicare benefits on a 

fee-for-service basis, or to enroll in an MA-PD and receive all of their Medicare benefits, 

including prescription drug coverage, through managed care. As of April 2015, 

approximately 39.1 million of the 53.6 million Medicare beneficiaries were enrolled in a 

Part D plan. 

Part D plans are administered by private companies, known as plan sponsors, that 

contract with CMS to offer prescription drug coverage in one or more PDP or MA-PD 

regions. CMS has designated 34 PDP regions and 26 MA-PD regions.10 In 2015, plan 

sponsors offer 3,152 unique Part D plans, with many plan sponsors offering multiple 

Part D plans. 

Dual Eligibles Under Medicare Part D 

Approximately 10.7 million Medicare beneficiaries are dual eligibles. About 7.7 million 

dual eligibles, referred to as “full-benefit dual eligibles,” receive full Medicaid benefits 

and may receive assistance with premiums and cost-sharing for Medicare fee-for-service 

or Medicare managed care.11 Other dual eligibles receive only assistance with their 

Medicare premiums or cost-sharing, depending on their level of income and assets. 

Dual eligibles are a particularly vulnerable population. Overall, most dual eligibles have 

very low incomes: 86 percent have annual incomes below 150 percent of the Federal 

poverty level, compared with 22 percent of all other Medicare beneficiaries.12 

Additionally, dual eligibles are in worse health than the average Medicare beneficiary: 

half are in fair or poor health, more than twice the rate of others in Medicare.13 Because 

of their self-reported health needs, dual eligibles may use more prescription drugs and 

health care services in general than other Medicare beneficiaries. 

Until December 31, 2005, dual eligibles received outpatient prescription drug benefits 

through Medicaid. In January 2006, Medicare began covering outpatient prescription 

drugs for dual eligibles through Part D plans.14 

9

 MMA, P.L. No. 108-173 § 101, Social Security Act, § 1860D-1(a). 

10 CMS, Prescription Drug Benefit Manual (PDBM), Pub. 100-18, ch. 5, Appendixes 2 and 3. Accessed at 

http://www.cms.gov/Medicare/Prescription-Drug-Coverage/PrescriptionDrugCovContra/ 

PartDManuals.html on April 14, 2015. 11 Centers for Medicare & Medicaid Services, Data Tables for Medicare-Medicaid Enrollment and 

Eligibility Trends, 2013. Accessed at http://www.cms.gov/Medicare-Medicaid-Coordination/Medicare-andMedicaid-Coordination/Medicare-Medicaid-Coordination-Office/Analytics.html on April 22, 2015.
 12 Kaiser Family Foundation, Medicare’s Role for Dual Eligible Beneficiaries. Accessed at 

http://www.kff.org/medicare/upload/8138-02.pdf on April 20, 2015. 13 Ibid. 

14 MMA, P.L. No. 108-173 § 101, Social Security Act, § 1860D-1(a). 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

 

 

Page 4 – Andrew M. Slavitt 

Medicare covers Part D plan premiums for dual eligibles up to a set benchmark. The 

benchmark is a statutorily defined amount that is based on the average premium amounts 

for Part D plans for each region.15, 16 If dual eligibles enroll in Part D plans with 

premiums higher than the regional benchmark, they are responsible for paying the 

premium amounts above that benchmark.17 

Dual eligibles’ assignment to Part D plans. When individuals become eligible for both 

Medicare and Medicaid, CMS randomly assigns those individuals to PDPs unless they 

have elected a specific Part D plan or have opted out of Part D prescription drug 

coverage.18 CMS assigns dual eligibles to PDPs that meet certain requirements, such as 

having a premium at or below the regional benchmark amount and offering basic 

prescription drug coverage (or equivalent).19 Basic prescription drug coverage is defined 

in terms of benefit structure (initial coverage, coverage gap, and catastrophic coverage) 

and costs (initial deductible and coinsurance). 

Some dual eligibles may be randomly assigned to PDPs that do not cover the specific 

drugs they use. However, unlike the general Medicare population, dual eligibles can 

switch plans at any time to find Part D plans that cover the prescription drugs they 

require.20 When dual eligibles change plans, their prescription drug coverage under the 

new Part D plan becomes effective at the beginning of the following month. 

CMS annually reassigns some dual eligibles to new PDPs if their current PDPs will have 

premiums above the regional benchmark premium for the following year.21 CMS 

reassigns dual eligibles who were randomly assigned to their current PDPs to new PDPs 

that will have premiums at or below the regional benchmark premium.22 In addition, 

CMS notifies dual eligibles who elected their current Part D plans that their plans will 

have premiums above the regional benchmark premium. For 2015, CMS reported 

reassigning approximately 372,000 Medicare beneficiaries, including but not exclusively 

dual eligibles, because of premium increases. 

Part D Prescription Drug Coverage 

Under Part D, plans can establish formularies from which they may exclude drugs and 

control drug utilization within certain parameters. These parameters are intended to 

15 Social Security Act, § 1860D-14(b); 42 CFR § 423.780(b)(2)(i).
 16 Dual eligibles residing in territories are not eligible to receive cost-sharing assistance from Medicare. As 

such, there are no benchmarks for Part D plans offered in the territories. Social Security Act, 

§ 1860D-14(a)(3)(F).
 17 The ACA established a “de minimis” premium policy, whereby a Part D plan may elect to charge dual 

eligibles the benchmark premium amount if the Part D plan’s basic premium exceeds the regional 

benchmark by a de minimis amount. Patient Protection and Affordable Care Act (ACA), P.L. No. 111-148
 

§ 3303, Social Security Act, § 1860D-14(a)(5). For 2014, CMS set the de minimis amount at $2 above the 

regional benchmark. 

18 CMS, PDBM, ch. 3, § 40.1.4. 

19 Ibid. 

20 Ibid., § 30.3.2. In general, Medicare beneficiaries can switch Part D plans only once a year during a 

defined enrollment period. 

21 Ibid., § 40.1.5.
 22 Ibid. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

 

 

 

Page 5 – Andrew M. Slavitt 

balance Medicare beneficiaries’ needs for adequate prescription drug coverage with 

Part D plans’ needs to contain costs. Generally, a formulary must include at least 

two drugs in each therapeutic category or class.23, 24 In addition, Part D plans must 

include Part D-covered drugs in certain categories and classes.25 

Part D plans may also control drug utilization by applying utilization management tools. 

These tools include requiring prior authorization to obtain drugs that are on plan 

formularies, establishing quantity limits, and requiring step therapy. Utilization 

management tools can help Part D plans and the Part D program limit the cost of 

prescription drug coverage by placing restrictions on the use of certain drugs. 

In addition to these drug coverage decisions made regarding individual formularies, 

certain categories of drugs are excluded from Medicare Part D prescription drug coverage 

as mandated by the MMA.26 For example, prescription vitamins, prescription mineral 

products, and nonprescription drugs are excluded from Part D prescription drug 

coverage.27 

Until 2013, barbiturates and benzodiazepines were excluded from Part D prescription 

drug coverage. However, the ACA reversed this exclusion, removing these two drug 

types from the list of drug classes ineligible for Part D prescription drug coverage.28,29 

CMS Efforts To Ensure Prescription Drug Coverage 

Formulary review. CMS annually reviews Part D plan formularies to ensure that they 

include a range of drugs in a broad distribution of therapeutic categories or classes and 

include all drugs in specified therapeutic categories or classes.30 During this review, 

CMS analyzes formularies’ coverage of the drug classes most commonly prescribed for 

the Medicare population. CMS intends for Part D plans to cover the most widely used 

medications, or therapeutically alternative medications (e.g., drugs from the same 

therapeutic category or class), for the most common conditions. CMS uses Part D 

prescription drug data to identify the most commonly prescribed classes of drugs.31 

23 CMS, PDBM, ch. 6, § 30.2.1. 24 Therapeutic categories or classes classify drugs according to their most common intended uses. For
 

example, cardiovascular agents compose a therapeutic class intended to affect the rate or intensity of
 

cardiac contraction, blood vessel diameter, or blood volume. 

25 Social Security Act, § 1860D-4(b)(3)(G). 

26 MMA, P.L. No. 108-173 § 101, Social Security Act, § 1860D-2(e). 

27 Social Security Act § 1860D-2(e)(2), 1927(d)(2).
 28 ACA, P.L. No. 111-148 § 2502, Social Security Act, § 1397r-8(d).
 29 CMS, Transition to Part D Coverage of Benzodiazepines and Barbiturates Beginning in 2013. Accessed 

at http://www.cms.gov/Medicare/Prescription-Drug-Coverage/PrescriptionDrugCovContra/Downloads/ 

BenzoandBarbituratesin2013.pdf, on April 29, 2015. 30 CMS, PDBM, ch. 6, § 30.2.7. 31 Ibid. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

Page 6 – Andrew M. Slavitt 

CMS also assesses each formulary’s utilization management tools to ensure consistency 

with current industry standards and with standards that are widely used with drugs for the 

elderly and people with disabilities.32, 33, 34 

Exceptions and appeals process. CMS has implemented an exceptions and appeals 

process whereby beneficiaries can request coverage of nonformulary drugs. 

Beneficiaries apply to their Part D plans for exceptions to obtain coverage of 

nonformulary drugs. Generally, Part D plans must make determinations within 72 hours 

or, for expedited requests, within 24 hours.35 If their plans make negative determinations, 

beneficiaries have the right to appeal.36 If their plans deny their appeals, beneficiaries 

would need to get prescriptions from their physicians for therapeutically alternative drugs 

that are covered by their plans. 

Transitioning new enrollees to Part D. CMS requires that Part D plans establish a 

transition process for new enrollees (including dual eligibles) who are transitioning to 

their respective Part D plans either from different Part D plans or from other prescription 

drug coverage. During Medicare beneficiaries’ first 90 days under a new Part D plan, the 

new plan must provide one temporary refill of a prescription when beneficiaries request 

either a drug that is not in the plan’s formulary or a drug that requires prior authorization 

or step therapy under the formulary’s utilization management tools.37 The temporary fill 

accommodates beneficiaries’ immediate drug needs the first time they attempt to fill a 

prescription. The transition period also allows beneficiaries time to work with their 

prescribing physicians to obtain prescriptions for therapeutically alternative drugs or to 

request formulary exceptions from Part D plans. 

Related OIG Work 

In 2006, OIG published a report assessing the extent to which PDP formularies included 

drugs commonly used by dual eligibles under Medicaid. The study found that PDP 

formularies included between 76 and 100 percent of the 178 drugs commonly used by 

dual eligibles under Medicaid prior to the implementation of Part D. Approximately half 

of the 178 commonly used drugs were covered by all formularies.38 

In 2011, OIG issued the first annual mandated memorandum report examining dual 

eligibles’ access to drugs under Medicare Part D.39 In 2012, OIG issued the second 

annual mandated memorandum report examining dual eligibles’ access to drugs under 

32 Ibid., § 30.2.2.
 33 Ibid., § 30.2.7.
 34 CMS looks to appropriate guidelines from expert organizations such as the National Committee for 

Quality Assurance, the Academy of Managed Care Pharmacy, and the National Association of Insurance 

Commissioners.
 35 CMS, PDBM, ch. 18, §§ 30.1 and 30.2. 36 Ibid., § 60.1. 37 Ibid., ch. 6, § 30.4.4. 

38 OIG, Dual Eligibles’ Transition: Part D Formularies’ Inclusion of Commonly Used Drugs, 

OEI-05-06-00090, January 2006. 

39 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles, OEI-05-10-00390, 

April 2011. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

 

Page 7 – Andrew M. Slavitt 

Medicare Part D.40 In 2013, OIG issued the third annual mandated memorandum report 

examining dual eligibles’ access to drug under Medicare Part D.41 In 2014, OIG issued 

the fourth annual mandated memorandum report.42 In the current memorandum report, 

we compare the results from 2014 and 2015. 

METHODOLOGY 

Scope 

As mandated in the ACA, this study assessed the extent to which drugs commonly used 

by dual eligibles are included by Part D plan formularies. To make this assessment, we 

evaluated formularies for Part D plans operating in 2015. As part of our assessment, we 

included dual eligibles’ enrollment data from April 2015, the most recent enrollment data 

available from CMS at the time of our study. We also compared the results of our 

2015 study with those of our 2014 study.43 

The ACA did not define which drugs commonly used by dual eligibles we should review. 

We defined drugs commonly used by dual eligibles as the 200 drugs with the highest 

utilization by dual eligibles as reported in the latest Medicare Current Beneficiary Survey 

(MCBS). We used the MCBS because it contains drugs that dual eligibles received 

through multiple sources (e.g., Part D, Medicaid, and the Department of Veterans 

Affairs) and, as such, it provides a comprehensive picture of drug utilization. Of the 

200 highest utilization drugs that we identified using the MCBS, 196 are eligible for 

coverage under Part D. In this report, we refer to these 196 Part D-eligible 

high-utilization drugs as “commonly used drugs.” 

The list of 200 drugs with the highest utilization by dual eligibles referenced in this 

2015 memorandum report is similar but not identical to the list of drugs referenced in the 

2014 memorandum report. Specifically, 185 of the 200 drugs (93 percent) listed in the 

2014 memorandum report are also listed in this 2015 memorandum report. 

For each study, OIG went beyond the ACA’s mandate by reviewing drug coverage for all 

dual eligibles under Medicare Part D, rather than only for full-benefit dual eligibles. 

With the data available for this study, we could not confidently identify and segregate 

full-benefit dual eligibles—and thus the drugs they used—from the total population of 

dual eligibles. 

We also went beyond the ACA’s mandate in the 2013, 2014, and 2015 reports by 

examining the utilization management tools that Part D plan formularies apply to the 

drugs commonly used by dual eligibles. These tools may affect dual eligibles’ access 

even in cases where formularies include the commonly used drugs. Analyzing the extent 

40 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2012, 

OEI-05-12-00060, June 2012. 

41 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2013, 

OEI-15-13-00090, June 2013.
 42 OIG, Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2014, 

OEI-05-14-00170, June 2014. 

43 Ibid. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

Page 8 – Andrew M. Slavitt 

to which Part D plan formularies apply these tools to drugs commonly used by dual 

eligibles allows us to provide a comprehensive picture of Part D plan formularies’ 

coverage of, and dual eligibles’ access to, those drugs. 

Data Sources 

MCBS. We used the 2011 MCBS Cost and Use data to create a list of the 200 drugs with 

the highest utilization by dual eligibles. The MCBS Cost and Use data contain 

information on hospitals, physicians, and prescription drug costs and utilization. The 

2011 MCBS Cost and Use data are the most recent data available. 

The MCBS is a continuous, multipurpose survey that CMS conducts of a representative 

national sample of the Medicare population, including dual eligibles. Sampled Medicare 

beneficiaries are interviewed three times per year and asked what drugs they are taking 

and whether they have started taking any new drugs since the previous interview. The 

MCBS also includes Part D prescription drug events for surveyed Medicare beneficiaries. 

In 2011, the MCBS surveyed 10,901 Medicare beneficiaries, of whom 2,149 were dual 

eligibles who had used prescription drugs during the year (out of 2,402 dual-eligible 

survey respondents). 

First Databank National Drug Data File. We used the April 2015 First DataBank 

National Drug Data File to identify the drug product information for the 200 drugs with 

the highest utilization by dual eligibles. The National Drug Data File is a database that 

contains information—such as drug name, therapeutic category or class, and the unique 

combination of active ingredients—for each drug as defined by a National Drug Code 

(NDC).44 

Part D plan data. In January 2015, we collected from CMS the formulary data and the 

plan data for Part D plans operating in 2015. The formulary data includes Part D plans’ 

formularies and utilization management tools for plans operating in 2015. In 2015, there 

are 341 unique formularies offered by 3,152 Part D plans. The plan data provides 

information such as the State in which a Part D plan is offered, whether the Part D plan is 

a PDP or an MA-PD, and whether the Part D plan premium is below the regional 

benchmark. 

We also collected 2015 enrollment data for Part D plans. These data provide the number 

of dual eligibles enrolled in each Part D plan as of April 2015. 

44 An NDC is a three-part universal identifier that specifies the drug manufacturer’s name, the drug form 

and strength, and the package size. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

Page 9 – Andrew M. Slavitt 

Determining the Most Commonly Used Drugs 

To determine the drugs most commonly used by dual eligibles, we took the following 

steps: 

1.	 We created a list of all drugs reported by dual eligibles surveyed in the MCBS. 

We excluded respondents from territories because they are not eligible to receive 

cost-sharing assistance under Part D. The MCBS listed 155,265 drug events for 

2,149 dual eligibles who did not reside in territories.45 

2.	 We collapsed this list to a list of drugs based on their active ingredients, using the 

Ingredient List Identifier located in First DataBank’s National Drug Data File. 

For example, a multiple-source drug such as fluoxetine hydrochloride (the active 

ingredient for the brand-name drug Prozac) has only one entry on our list, 

covering all strengths of both the brand-name drug Prozac and the available 

generic versions of fluoxetine hydrochloride. From this point forward, unless 

otherwise stated, we will use the term “drug” to refer to any drug in the same 

Ingredient List Identifier category, and the term “unique drug” to refer to an NDC 

corresponding to a drug, as a given drug can have multiple NDCs. This process 

left 155,265 drug events associated with 872 drugs. 

3.	 We ranked the 872 drugs by frequency of utilization, weighting the drug-event 

information from MCBS by sample weight. 

4.	 We selected the 200 drugs with the highest utilization by dual eligibles. For a full 

list of the top 200 drugs, see Appendix B. 

5.	 We removed all drugs not covered under Part D. Of the 200 drugs with the 

highest utilization, 196 are eligible under Part D. Three fell into drug categories 

excluded under Part D, and one is no longer prescribed in the form taken by 

beneficiaries surveyed in the 2011 MCBS. For details on these four drugs, see 

Appendix C. 

Formulary Analysis 

We analyzed the 341 unique Part D plan formularies to determine their rates of inclusion 

of the 196 drugs commonly used by dual eligibles. We counted a drug as included in a 

Part D plan’s formulary if the formulary included the active ingredient. When a drug 

included multiple ingredients that could be dispensed separately and combined by the 

patient to the same effect as the combined drug, we treated the drug as included if the 

ingredients were included in the formulary either separately or in combination. 

Low rates of inclusion by formularies. We determined which of the 196 commonly used 

drugs had low rates of inclusion by formularies by counting how many of the 

45 For the purposes of this report, a drug event is an MCBS survey response indicating that the responding 

beneficiary took a specific drug at least once in 2011. For example, one MCBS survey respondent reported 

taking zolpidem tartrate (Ambien) seven times in 2011. We counted this beneficiary/drug combination as 

seven drug events. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 10 – Andrew M. Slavitt 

341 formularies covered each drug. We considered a drug to have a low rate of inclusion 

if it was included by 75 percent or less of formularies. For such drugs, we counted the 

number of drugs (if any) that each formulary covered in the same therapeutic category or 

class. 

We conducted this analysis to ensure that dual eligibles have access to therapeutically 

similar drugs. We also conducted additional research to identify potential reasons why 

some of the 196 commonly used drugs were included by 75 percent or less of 

formularies. 

Utilization management tools. We determined the extent to which Part D plans apply 

utilization management tools to the 196 drugs that we reviewed. The tools that we 

reviewed are prior authorization, quantity limits, and step therapy. 

To determine the extent to which the 196 commonly used drugs are subject to utilization 

management tools, we conducted an analysis of the NDCs that correspond to the 

commonly used drugs. Part D plan formularies do not apply utilization management 

tools at the active ingredient level. Rather, Part D plan formularies apply utilization 

management tools at a more specific level that identifies whether a drug is brand-name or 

generic and its dosage form, strength, and route of administration, irrespective of package 

size. To conduct this analysis, we determined the NDCs (unique drugs) associated with 

each of the 196 commonly used drugs that are on each Part D formulary. We then 

calculated the percentage of unique drugs to which each Part D plan formulary applies 

utilization management tools. 

Enrollment Analysis 

We weighted the formulary analysis by dual-eligible enrollment and weighted the 

analysis of utilization management tools by both dual-eligible enrollment and Medicare 

enrollment. To do this, we applied enrollment data from April 2015 to Part D plans 

available in 2015. 

Data Limitations 

We did not assess individual dual eligibles’ prescription drug use or whether individual 

dual eligibles are enrolled in Part D plans that include the specific drugs that each 

individual uses. Because we relied on a sample of dual eligibles responding to the MCBS 

to develop our list of commonly used drugs, a particular dual eligible might not use any 

of the drugs on our list. However, the drugs most commonly used by dual-eligible 

MCBS survey participants in 2011 account for 88 percent of all prescriptions dispensed 

to the dual-eligible respondents in the 2011 MCBS. 

Because the lists of commonly used drugs in the 2014 and 2015 memorandum reports are 

not identical, the changes in rates of inclusion by formularies and in application of 

utilization management tools between 2014 and 2015 may reflect changes as to which 

specific drugs were included in the lists, rather than changes regarding any specific drug. 

However, the two lists largely overlap; 93 percent of the drugs on the list in our 

2014 report were also on the list in this 2015 memorandum report. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 11 – Andrew M. Slavitt 

Standards 

This study was conducted in accordance with the Quality Standards for Inspection and 

Evaluation issued by the Council of the Inspectors General on Integrity and Efficiency. 

RESULTS 

Part D Plan Formularies Include Between 86 and 100 Percent of the Drugs 

Commonly Used by Dual Eligibles 

On average, Part D plan formularies include 95 percent of the drugs commonly used by 

dual eligibles. Of the 341 unique formularies used by Part D plans in 2015, 

12 formularies include 100 percent of the commonly used drugs. At the other end of the 

inclusion range, one formulary includes 86 percent of the commonly used drugs. CMS 

generally requires Part D plan formularies to include at least two drugs—rather than all 

drugs—in each therapeutic category or class. Therefore, Part D plan formularies may 

still meet CMS’s formulary requirements even if they do not include all of the drugs we 

identified as commonly used by dual eligibles. 

Part D plan formularies’ rate of inclusion of the drugs commonly used by dual eligibles 

in 2015 is nearly identical to that of 2014. The average rate of inclusion decreased 

slightly between 2014 and 2015, from 96 percent to 95 percent. The range of inclusion 

rates was the same in 2015 as in 2014—from 86 to 100 percent of the drugs. 

Nationally, PDP and MA-PD formularies have similar rates of inclusion of the drugs 

commonly used by dual eligibles, averaging 94 percent and 95 percent, respectively. For 

PDP formularies, the rates of inclusion ranged from 88 to 100 percent; for MA-PD 

formularies, they ranged from 86 to 100 percent. Eighteen formularies—5 percent of the 

341 unique formularies used by Part D plans in 2015—are offered by both PDPs and 

MA-PDs. 

Regionally, all dual eligibles have the choice of a Part D plan that includes at least 

98 percent of the commonly used drugs. Every PDP region has a plan that includes at 

least 98 percent of the commonly used drugs, and every MA-PD region has a plan that 

includes at least 98 percent of these drugs. Appendix D provides a breakdown of 

formularies’ rates of inclusion of the drugs by PDP and MA-PD region. 

On average, formularies for Part D plans with premiums below the regional benchmark 

include 95 percent of the drugs commonly used by dual eligibles. The percentage of 

drugs included by Part D plans with premiums below the regional benchmark is 

important because dual eligibles are automatically enrolled in, or annually reassigned to, 

such plans. For drugs commonly used by dual eligibles, formularies for such plans have 

rates of inclusion that range from 88 percent to 100 percent. Approximately 86 percent 

of dual eligibles are enrolled in Part D plans with premiums below the regional 

benchmark. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

Page 12 – Andrew M. Slavitt 

Ninety-four percent of dual eligibles are enrolled in Part D plans that include at least 

90 percent of the drugs commonly used by dual eligibles. Of the approximately 

9.7 million dual eligibles enrolled in Part D plans, 94 percent are enrolled in Part D plans 

that use formularies that include at least 90 percent of the commonly used drugs. Only 

6 percent of dual eligibles are enrolled in Part D plans that use formularies that include 

less than 90 percent of these drugs. Table 1 provides a breakdown of dual eligibles’ 

enrollment in Part D plans by the plans’ formulary inclusion rates. 

Table 1: Enrollment of Dual Eligibles in Part D Plans and Formulary 

Inclusion of Commonly Used Drugs 

Part D Plans With Formularies That 

Include: 

Number of Dual 

Eligibles Enrolled* 

Percentage of Dual 

Eligibles Enrolled 

100% of commonly used drugs 159,954 2% 

95% to 99% of commonly used drugs 2,209,253 23% 

90% to 94% of commonly used drugs 6,866,185 70% 

85% to 89% of commonly used drugs 548,415 6%

 Total 9,783,807 100%** 

Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles and dual eligibles’ 

enrollment, 2015. 

*Rounded to the nearest 1,000. 

**Percentages do not add to 100 percent because of rounding. 

The percentage of dual eligibles enrolled in Part D plans that include at least 90 percent 

of the drugs commonly used by dual eligibles decreased from 99 percent in 2014 to 

94 percent in 2015. 

Sixty-Six Percent of the Drugs Commonly Used by Dual Eligibles Are Included in 

All Part D Plan Formularies 

Because most of the commonly used drugs are included in a large percentage of 

formularies, dual eligibles are guaranteed that regardless of the Part D plan in which they 

are enrolled, the plan’s formulary will include many of these drugs. By drug, formulary 

inclusion ranges from 33 percent to 100 percent. At one end of the range, there is 

a commonly used drug that is included in 33 percent of Part D plan formularies, and at 

the other end, 130 drugs are included in all plan formularies. The average rate of 

inclusion by formularies is 95 percent. Table 2 provides a summary of rates of inclusion 

by formularies. Appendix B lists the commonly used drugs and their respective rates of 

inclusion by formularies. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 13 – Andrew M. Slavitt 

Table 2: Formularies’ Rates of Inclusion of Commonly Used Drugs 

Percentage of the 341 Formularies 

Percentage of the 196 Commonly 

Used Drugs Included in 

Formularies 

100% 66% 

(130 drugs) 

85% to 99% 21% 

(42 drugs) 

76% to 84% 7% 

(13 drugs) 

33% to 75% 6% 

(11 drugs)

 Total 100% 

(196 drugs) 

Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2015. 

The rates of formulary inclusion of the drugs commonly used by dual eligibles in 2015 

are similar to those in 2014. The percentage of commonly used drugs included in all 

formularies increased slightly between 2014 and 2015, from 64 percent to 66 percent. 

Part D plan formularies include certain drugs less frequently than others. Of the 

commonly used drugs, 6 percent (11 drugs) are included by 75 percent or less of Part D 

plan formularies. Table 3 provides the percentage of formularies covering each of these 

11 drugs. 

The drugs that make up this group include both brand-name and generic drugs, and are 

used to treat a variety of primary indications. Six of the eleven drugs are brand-name 

drugs, which are typically more costly than generic drugs. As for the primary 

indications, 3 of the 11 drugs are used for diabetic therapy, 2 of the 11 drugs are muscle 

relaxants, and the remaining drugs treat a variety of conditions including overactive 

bladder, high cholesterol, anxiety, and hypertension. 

Table 3: Drugs Included by 75 Percent or Less of Part D Plan Formularies 

Generic Name of Drug Primary Indication(s) 

Rate of 

Inclusion by 

Formularies 

Insulin lispro Diabetes 75% 

Valsartan* Hypertension (high blood pressure) 67% 

Glyburide/metformin HCl Diabetes 62% 

Glyburide Diabetes 61% 

Conjugated estrogen/medroxyprogesterone 

acet Menopause 59% 

Ezetimibe/simvastatin* Hyperlipidemia (high cholesterol) 57% 

Methocarbamol* Musculoskeletal pain 55% 

Esomeprazole magnesium* Dyspepsia, peptic ulcer disease, gastroesophageal reflux 

disease, Zollinger-Ellison syndrome 49% 

Hydroxyzine pamoate* Anxiety 46% 

Carisoprodol* Musculoskeletal pain 42% 

Darifenacin hydrobromide* Overactive bladder 33% 

Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2015. 

* These drugs also had low formulary inclusion rates in 2014. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

 

 

Page 14 – Andrew M. Slavitt 

Although Part D formularies frequently omit these 11 drugs, they all cover other drugs in 

the same therapeutic classes. For these 11 drugs, 100 percent of formularies cover at 

least 1 drug in the same therapeutic class that is also on the list of 196 drugs commonly 

used by dual eligibles. 

The number of drugs included by 75 percent or less of formularies stayed the same— 

11 drugs—in 2014 and 2015. There are seven drugs with low inclusion rates in 2015 that 

were also on the list of commonly used drugs with low inclusion rates in our 2014 report; 

these drugs are noted in Table 3. Five of these seven drugs were also on the list of drugs 

with low inclusion rates in our 2013 report. 

There are many potential reasons why a commonly used drug might be included by 

75 percent or less of formularies: 

 Four of these drugs—methocarbamol, carisoprodol, conjugated estrogen/ 

medroxyprogesterone, and hydroxyzine pamoate—are on CMS’s list of Part D 

medications that are high-risk for the elderly.46 

 Further, seven of these drugs—carisoprodol, darifenacin hydrobromide, 

hydroxyzine pamoate, methocarbamol, glyburide, glyburide/metformin HCl, and 

estrogens—are listed by the American Geriatrics Society as being potentially 

inappropriate for older adults.47 

Low rates of inclusion by formularies may require dual eligibles to obtain a nonformulary 

drug. There are several means by which dual eligibles can obtain a nonformulary drug, 

all of which require them to take additional action. Obtaining therapeutically alternative 

drugs requires that dual eligibles get new prescriptions from their doctors. Dual eligibles 

may also submit statements of medical necessity from their physicians as part of appeals 

to obtain coverage of nonformulary drugs.48 Finally, dual eligibles may switch to Part D 

plans that include their drugs, with the new coverage becoming effective the following 

month.49 

46 This list—“Use of High-Risk Medications in the Elderly: High-Risk Medications” —is part of the
 

Healthcare Effectiveness and Information Set national drug code measures published by the National
 

Committee for Quality Assurance. A drug that is listed as being high risk for the elderly is one that has a 

high risk of serious side effects in that population. CMS uses this medication list to calculate the 

percentage of Medicare beneficiaries who received at least one high-risk medication in the past year. CMS 

publishes this percentage and other measures of Part D patient safety so that Medicare beneficiaries can 

make informed decision in choosing a Part D plan for their prescription drug coverage. National
 

Committee on Quality Assurance, HEDIS 2012 NDC List. Accessed at 

http://www.cms.gov/Medicare/Prescription-Drug-Coverage/PrescriptionDrugCovContra/Downloads/ 

MemoPatientSafetyMeasures_071610.pdf on April 15, 2015. 47 The American Geriatrics Society, American Geriatrics Society Updated Beers Criteria for Potentially 

Inappropriate Medication Use in Older Adults, 2012. 48 CMS, PDBM, ch. 18, § 30.2.2.
 49 Ibid., ch. 3, § 30.3.2.
 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

Page 15 – Andrew M. Slavitt 

The Percentage of Commonly Used Drugs Subject to Utilization Management Tools 

by Plan Formularies Increased Slightly Between 2014 and 2015 

For the unique drugs that compose the list of commonly used drugs, the percentage 

subject to utilization management tools by Part D plan formularies increased slightly 

from an average of 28 percent in 2014 to an average of 29 percent in 2015. Formularies 

for plans with premiums below and those with premiums above the regional benchmarks 

had a similar percentage of drugs—27 percent and 29 percent, respectively—that were 

subject to utilization management tools. See Table 4 for a breakdown of the percentage 

of unique drugs to which Part D plan formularies apply utilization management tools in 

2014 and 2015. 

Table 4: Part D Plan Formularies’ Application of Utilization Management Tools to 

Commonly Used Drugs, 2014 and 2015 

Percentage of Unique Drugs 

to Which Utilization 

Management Tools Are 

Applied 

Number of 

2014 Part D 

Plan 

Formularies 

Percentage of 

2014 Part D 

Plan 

Formularies 

Number of 

2015 Part D 

Plan 

Formularies 

Percentage of 

2015 Part D Plan 

Formularies 

Greater than 40% 30 9% 49 14% 

30% to 39% 136 41% 137 40% 

20% to 29% 65 20% 66 19% 

10% to 19% 75 23% 65 19% 

Less than 10% 23 7% 24 7%

 Totals 329 100% 341 100%* 

Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2015. 

* Percentages do not add to 100 percent because of rounding. 

The percentage of drugs subject to quantity limits or prior authorization increased slightly 

from 2014 to 2015, while the percentage of drugs subject to step therapy remained the 

same. Formularies’ use of quantity limits and use of prior authorization each increased 

by 1 percent—from 24 to 25 percent and from 3 to 4 percent of unique drugs, 

respectively. The percentage of unique drugs for which formularies required step therapy 

was 2 percent in both 2014 and 2015. 

The rate at which plan formularies apply specific utilization management tools varies 

widely. In 2015, some formularies applied utilization management tools to none of the 

unique drugs, whereas at the other end of the range, some applied tools to 47 percent of 

the unique drugs. More specifically, formularies apply quantity limits to between 0 and 

43 percent of unique drugs, require prior authorization for between 0 and 10 percent, and 

require step therapy for between 0 and 15 percent. 

Looking at enrollment across plans provides a slightly different picture than looking only 

at plans themselves. On average, plan formularies in 2015 apply utilization management 

tools to 29 percent of unique drugs. However, dual eligibles tend to be enrolled in plans 

with formularies that apply these tools at a slightly higher rate. In 2015, the median plan 

weighted by dual-eligible enrollment applies such tools to 35 percent of unique drugs; in 

2014, the figure was 34 percent. Similarly, the median plan weighted by overall 

Medicare enrollment applies these tools to 34 percent of unique drugs in 2015; in 2014, 

the figure was 33 percent. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

Page 16 – Andrew M. Slavitt 

Both dual eligibles and Medicare beneficiaries overall tend to be enrolled in plans with 

formularies that apply utilization management tools to between 30 and 47 percent of 

unique drugs. In 2015, 63 percent of dual eligibles and 57 percent of Medicare 

beneficiaries overall were enrolled in plans with formularies in this range. Table 5 shows 

enrollment in Part D plans by dual eligibles and Mediciare beneficiaries, as broken down 

by the percentages at which the plans’ formularies’ apply utilization management tools. 

Table 5: Beneficiary Enrollment in Part D Plans by Application of Utilization 

Management Tools to Commonly Used Drugs, 2014 and 2015
 

Percentage of Unique Drugs to 

Which Plan Formularies Apply 

Utilization Management Tools 

Percentage of 

Dual Eligibles 

Enrolled, 2014 

Percentage of 

Medicare 

Beneficiaries 

Enrolled, 2014 

Percentage of 

Dual Eligibles 

Enrolled, 2015 

Percentage of 

Medicare 

Beneficiaries 

Enrolled, 2015 

Greater than 40% 5% 14% 8% 16% 

30% to 39% 63% 44% 54% 41% 

20% to 29% 7% 6% 32% 34% 

10% to 19% 24% 32% 4% 5% 

Less than 10% 2% 4% 2% 3%

 Totals 100%* 100% 100% 100%* 

Source: OIG analysis of dual-eligible enrollment and Medicaid beneficiary enrollment by rates of utilization management tool
 

application to drugs commonly used by dual eligibles, 2015. 

*Percentages do not add to 100 percent because of rounding.
 

Further, although utilization management tools control access to drugs, they are 

important tools for managing costs in Medicare and ensuring appropriate utilization of 

drugs. For example, oxycodone HCl/acetaminophen drugs saw more than a 30-percent 

increase in formulary application of utilization management controls in 2013. Such 

limits may be intended to ensure appropriate utilization, as CMS’s Part D 2013 guidance 

to Part D sponsors set forth expectations for reviews of opioid overutilization to help 

ensure that opioids are prescribed and used correctly.50 

CONCLUSION 

When establishing formularies and applying utilization management tools, Part D plans 

need to balance Medicare beneficiaries’ needs for adequate prescription drug coverage 

with the need to contain costs for themselves and for the Part D program. By law, Part D 

plan formularies do not have to include every available drug. Rather, to meet CMS’s 

formulary requirements, they must include at least two drugs in each therapeutic category 

or class. For example, for each of the 11 drugs that this memorandum report identifies as 

being included by 75 percent or less of Part D plan formularies, all Part D plan 

formularies cover at least one therapeutically alternative drug. Part D plan formularies 

may also institute utilization management tools to ensure appropriate utilization as well 

as to control costs. 

For the drugs commonly used by dual eligibles, we found that the rate of formulary 

inclusion is high with some variation. On average, Part D plan formularies include 

50 CMS, Supplemental Guidance Related to Improving Drug Utilization Review Controls in Part D. 

Accessed at https://www.cms.gov/Medicare/Prescription-Drug-Coverage/PrescriptionDrugCovContra/ 

Downloads/HPMSSupplementalGuidanceRelated-toImprovingDURcontrols.pdf on April 29, 2015. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 17 – Andrew M. Slavitt 

95 percent of the commonly used drugs. Part D plan formularies’ inclusion of the 

commonly used drugs ranges from 86 percent to 100 percent. Formulary inclusion rates 

are similar for PDPs and MA-PDs. Further, formularies for Part D plans with premiums 

below the regional benchmark include the commonly used drugs at a rate similar to that 

of Part D plan formularies overall. 

Inclusion rates for the 196 drugs commonly used by dual eligibles are largely unchanged 

compared with those from OIG’s 2014 memorandum report. Part D plan formularies 

include roughly the same percentage of these commonly used drugs in 2015 as they did 

in 2014. Enrollment in plans that cover at least 90 percent of unique drugs decreased 

slightly, with 94 percent of dual eligibles enrolled in such plans in 2015 compared to 

99 percent in 2014. 

Because some variation exists in Part D plan formularies’ inclusion of the commonly 

used drugs and in their application of utilization management tools to these drugs, some 

dual eligibles may need to use alternative methods to access the drugs they take. They 

could appeal prescription drug coverage decisions, switch prescription drugs, or switch 

Part D plans. These scenarios require additional effort by dual eligibles and may result in 

administrative barriers to accessing certain prescription drugs. 

As mandated by the ACA, OIG will continue to monitor the extent to which Part D plan 

formularies cover drugs that dual eligibles commonly use. In addition, OIG will continue 

to monitor Part D plan formularies’ application of utilization management tools to these 

drugs. 

This memorandum report is being issued directly in final form because it contains no 

recommendations. We have included the list of the 200 drugs with the highest utilization 

by dual eligibles. If you have comments or questions about this memorandum report, 

please provide them within 60 days. Please refer to report number OEI-05-15-00120 in 

all correspondence. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 18 – Andrew M. Slavitt 

APPENDIX A 

Section 3313 of the Patient Protection and Affordable Care Act of 2010 

SEC. 3313. OFFICE OF THE INSPECTOR GENERAL STUDIES AND REPORTS. 

(a) STUDY AND ANNUAL REPORT ON PART D FORMULARIES’ INCLUSION 

OF DRUGS COMMONLY USED BY DUAL ELIGIBLES.— 

(1) STUDY.—The Inspector General of the Department of Health and Human Services 

shall conduct a study of the extent to which formularies used by prescription drug plans 

and MA-PD plans under Part D include drugs commonly used by full benefit dual 

eligible individuals (as defined in section 1935(c)(6) of the Social Security Act 

(42 U.S.C. 1396u–5(c)(6)). 

(2) ANNUAL REPORTS.—Not later than July 1 of each year (beginning with 2011), the 

Inspector General shall submit to Congress a report on the study conducted under 

paragraph (1), together with such recommendations as the Inspector General determines 

appropriate. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

 

 

 

 

 

 

 

 

 

Page 19 – Andrew M. Slavitt 

APPENDIX B 

Commonly Used Drugs and Rates of Inclusion by Formularies 

Table B-1: 200 Drugs With the Highest Utilization by Dual Eligibles 

Generic Name Sample 

Size* 

Projected 

Drugs* 

95-Percent Confidence 

Interval* 

Number of 

Formularies 

Including 

Percentage of 

Formularies 

Including 

Simvastatin 3,900 17,347,406 15,514,367–19,180,445 340 100% 

Lisinopril 3,853 17,267,881 15,114,378–19,421,384 341 100% 

Hydrocodone/acetaminophen 4,632 16,947,722 15,258,697–18,636,747 341 100% 

Omeprazole 4,014 15,672,875 14,093,417–17,252,333 341 100% 

Levothyroxine sodium 3,476 14,830,579 13,126,542–16,534,615 341 100% 

Furosemide 3,428 14,434,347 12,915,250–15,953,443 341 100% 

Amlodipine besylate 2,919 13,077,400 11,368,250–14,786,550 341 100% 

Metformin HCl 2,865 12,804,478 11,154,960–14,453,996 341 100% 

Potassium chloride 2,745 10,583,238 9,213,268–11,953,209 341 100% 

Metoprolol tartrate 2,352 9,997,980 8,527,265–11,468,696 341 100% 

Gabapentin 1,856 7,678,814 6,546,945–8,810,682 341 100% 

Warfarin sodium 1,969 7,669,750 6,220,257–9,119,244 341 100% 

Atorvastatin calcium 1,658 7,345,895 6,149,446–8,542,344 341 100% 

Hydrochlorothiazide 1,557 6,986,485 5,967,217–8,005,753 341 100% 

Clopidogrel bisulfate 1,544 6,943,517 5,750,562–8,136,471 341 100% 

Albuterol sulfate 1,594 6,785,246 5,751,649–7,818,843 341 100% 

Esomeprazole magnesium 1,409 6,620,580 5,333,170–7,907,989 167 49% 

Citalopram hydrobromide 1,680 6,426,818 5,291,102–7,562,533 341 100% 

Atenolol 1,308 6,334,483 5,181,329–7,487,637 341 100% 

Tramadol HCl 1,443 5,544,220 4,444,084–6,644,356 341 100% 

Zolpidem tartrate 1,310 5,454,634 4,429,932–6,479,336 328 96% 

Carvedilol 1,236 5,320,616 4,330,462–6,310,771 341 100% 

Ranitidine HCl 1,381 5,134,725 3,948,479–6,320,972 341 100% 

Valsartan 1,074 4,944,768 3,960,182–5,929,353 228 67% 

Trazodone HCl 1,289 4,925,948 3,836,052–6,015,844 341 100% 

Oxycodone 

HCl/acetaminophen 

1,346 4,865,501 3,572,611–6,158,391 341 100% 

Glipizide 1,118 4,768,378 3,897,329–5,639,428 341 100% 

Sertraline HCl 1,186 4,657,331 3,757,053–5,557,609 341 100% 

Fluticasone/salmeterol 1,037 4,647,993 3,735,988–5,559,997 304 89% 

Metoprolol succinate 874 4,576,199 3,687,311–5,465,088 340 100% 

Insulin glargine,hum.rec.anlog 1,057 4,519,573 3,638,096–5,401,051 329 96% 

Alendronate sodium 1,098 4,517,069 3,714,312–5,319,827 341 100% 

Risperidone 1,337 4,321,416 3,370,755–5,272,076 341 100% 

Quetiapine fumarate 1,486 4,139,968 3,230,748–5,049,188 341 100% 

continued on next page 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 20 – Andrew M. Slavitt 

Table B-1: 200 Drugs With the Highest Utilization by Dual Eligibles, continued 

Generic Name Sample 

Size* 

Projected 

Drugs* 

95-Percent Confidence 

Interval* 

Number of 

Formularies 

Including 

Percentage of 

Formularies 

Including 

Prednisone 1,043 4,060,613 3,342,786–4,778,439 341 100% 

Fluticasone propionate 967 3,994,341 3,322,845–4,665,836 341 100% 

Rosuvastatin calcium 749 3,946,728 3,150,322–4,743,134 279 82% 

Pravastatin sodium 792 3,669,913 2,920,688–4,419,137 341 100% 

Donepezil HCl 1,100 3,629,564 2,875,141–4,383,988 341 100% 

Isosorbide mononitrate 748 3,561,729 2,815,323–4,308,136 341 100% 

Cyclobenzaprine HCl 802 3,507,572 2,743,874–4,271,270 340 100% 

Montelukast sodium 845 3,433,580 2,539,837–4,327,323 341 100% 

Pioglitazone HCl 740 3,315,739 2,511,944–4,119,534 341 100% 

Diltiazem HCl 791 3,236,508 2,409,349–4,063,667 341 100% 

Clonidine HCl 785 3,207,052 2,329,831–4,084,273 341 100% 

Lovastatin 655 3,180,423 2,491,792–3,869,054 338 99% 

Divalproex sodium 1,080 3,083,963 2,353,057–3,814,868 341 100% 

Meloxicam 715 3,045,674 2,442,247–3,649,102 340 100% 

Famotidine 716 3,002,313 2,222,260–3,782,365 340 100% 

Allopurinol 721 2,959,137 2,201,749–3,716,525 341 100% 

Ibuprofen 828 2,920,144 2,333,892–3,506,396 341 100% 

Escitalopram oxalate 858 2,894,303 2,278,119–3,510,486 340 100% 

Losartan potassium 587 2,883,618 2,142,589–3,624,648 341 100% 

Bupropion HCl 689 2,871,472 2,059,562–3,683,383 341 100% 

Amitriptyline HCl 666 2,871,130 1,827,969–3,914,291 341 100% 

Glimepiride 632 2,851,481 2,001,228–3,701,734 341 100% 

Lisinopril/hydrochlorothiazide 563 2,838,412 2,174,963–3,501,861 341 100% 

Pantoprazole sodium 620 2,784,126 2,004,950–3,563,302 340 100% 

Tiotropium bromide 593 2,775,253 2,119,646–3,430,860 332 97% 

Tamsulosin HCl 670 2,757,815 2,144,214–3,371,415 341 100% 

Azithromycin 723 2,640,943 2,265,620–3,016,265 341 100% 

Oxycodone HCl 773 2,593,236 1,865,688–3,320,784 341 100% 

Paroxetine HCl 692 2,592,058 1,793,177–3,390,938 341 100% 

Duloxetine HCl 664 2,529,408 1,768,441–3,290,374 341 100% 

Aripiprazole 784 2,509,941 1,849,321–3,170,561 341 100% 

Alprazolam 722 2,507,449 1,908,250–3,106,648 313 92% 

Celecoxib 549 2,487,716 1,753,302–3,222,130 272 80% 

Enalapril maleate 628 2,486,122 1,773,448–3,198,796 341 100% 

Triamterene/hydrochlorothiazide 489 2,472,394 1,698,398–3,246,390 341 100% 

Fluoxetine HCl 671 2,442,283 1,858,877–3,025,689 341 100% 

Lansoprazole 520 2,432,783 1,664,326–3,201,239 272 80% 

continued on next page 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 21 – Andrew M. Slavitt 

Table B-1: 200 Drugs With the Highest Utilization by Dual Eligibles, continued 

Generic Name Sample 

Size* 

Projected 

Drugs* 

95-Percent Confidence 

Interval* 

Number of 

Formularies 

Including 

Percentage of 

Formularies 

Including 

Memantine HCl 676 2,342,026 1,726,810–2,957,242 341 100% 

Clonazepam 646 2,266,382 1,667,334–2,865,431 341 100% 

Fexofenadine HCl 516 2,230,968 1,530,394–2,931,543 

Benztropine mesylate 805 2,226,864 1,615,882–2,837,845 340 100% 

Ezetimibe 418 2,160,362 1,594,728–2,725,996 339 99% 

Naproxen 557 2,141,422 1,665,511–2,617,333 341 100% 

Carisoprodol 504 2,069,351 1,346,367–2,792,335 144 42% 

Spironolactone 481 2,061,652 1,505,827–2,617,477 341 100% 

Sulfamethoxazole/ 

trimethoprim 

636 2,057,059 1,708,114–2,406,003 341 100% 

Diclofenac sodium 477 2,044,525 1,547,162–2,541,887 341 100% 

Valsartan/ 

hydrochlorothiazide 

430 2,030,978 1,418,545–2,643,412 331 97% 

Ciprofloxacin HCl 608 2,001,235 1,755,947–2,246,522 341 100% 

Topiramate 720 1,991,977 1,240,195–2,743,760 341 100% 

Mirtazapine 641 1,962,056 1,543,919–2,380,194 341 100% 

Carbamazepine 595 1,924,763 1,352,454–2,497,073 341 100% 

Promethazine HCl 527 1,911,351 1,452,229–2,370,473 293 86% 

Meclizine HCl 399 1,906,646 1,148,154–2,665,138 341 100% 

Cephalexin 511 1,899,305 1,508,958–2,289,651 341 100% 

Fenofibrate nanocrystallized 413 1,898,960 1,336,984–2,460,935 315 92% 

Ipratropium/albuterol sulfate 463 1,888,932 1,347,400–2,430,464 333 98% 

Venlafaxine HCl 627 1,861,582 1,234,559–2,488,604 341 100% 

Oxybutynin chloride 568 1,849,363 1,498,605–2,200,122 341 100% 

Morphine sulfate 491 1,845,759 1,195,157–2,496,362 341 100% 

Digoxin 515 1,845,656 1,427,800–2,263,512 341 100% 

Olanzapine 627 1,790,633 1,160,005–2,421,261 341 100% 

Lorazepam 540 1,786,878 1,296,097–2,277,659 341 100% 

Verapamil HCl 387 1,786,033 1,240,416–2,331,649 341 100% 

Levetiracetam 543 1,782,579 1,162,363–2,402,794 341 100% 

Nitroglycerin 436 1,738,085 1,318,075–2,158,095 341 100% 

Propranolol HCl 420 1,722,294 989,518–2,455,070 341 100% 

Pramipexole di-HCl 340 1,721,576 526,539–2,916,613 341 100% 

Pregabalin 498 1,699,388 1,279,765–2,119,011 341 100% 

Glyburide 357 1,698,601 1,266,404–2,130,799 207 61% 

Travoprost 378 1,669,219 1,101,440–2,236,998 300 88% 

Nifedipine 409 1,664,761 1,178,345–2,151,176 329 96% 

Insulin aspart 452 1,659,889 1,219,121–2,100,657 276 81% 

continued on next page 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 22 – Andrew M. Slavitt 

Table B-1: 200 Drugs With the Highest Utilization by Dual Eligibles, continued 

Generic Name Sample 

Size* 

Projected 

Drugs* 

95-Percent Confidence 

Interval* 

Number of 

Formularies 

Including 

Percentage of 

Formularies 

Including 

Lidocaine 432 1,643,259 1,137,819–2,148,699 341 100% 

Phenytoin sodium extended 514 1,576,690 1,162,249–1,991,130 341 100% 

Polyethylene glycol 3350 471 1,567,563 1,246,909–1,888,216 341 100% 

Buspirone HCl 395 1,563,876 1,033,893–2,093,859 341 100% 

Hydroxyzine HCl 432 1,563,435 1,170,925–1,955,945 266 78% 

Baclofen 457 1,536,847 996,284–2,077,411 341 100% 

Hydralazine HCl 369 1,460,232 1,067,908–1,852,555 341 100% 

Sitagliptin phosphate 308 1,451,576 857,459–2,045,694 326 96% 

Ipratropium bromide 283 1,406,253 766,035–2,046,471 341 100% 

Benazepril HCl 269 1,401,998 938,298–1,865,698 340 100% 

Fentanyl 420 1,388,578 870,924–1,906,232 341 100% 

Latanoprost 360 1,377,318 1,061,923–1,692,713 341 100% 

Amoxicillin 384 1,369,672 1,162,573–1,576,772 341 100% 

Lamotrigine 522 1,343,506 915,124–1,771,888 341 100% 

Insulin regular, human 387 1,330,468 885,107–1,775,828 341 100% 

Doxazosin mesylate 322 1,326,945 924,407–1,729,482 341 100% 

Acetaminophen with codeine 358 1,306,922 931,475–1,682,370 341 100% 

Levofloxacin 338 1,289,250 1,014,165–1,564,336 341 100% 

Gemfibrozil 322 1,271,415 854,041–1,688,788 341 100% 

Ropinirole HCl 306 1,239,322 736,045–1,742,599 341 100% 

Tizanidine HCl 416 1,235,871 775,568–1,696,175 341 100% 

Ezetimibe/simvastatin 258 1,190,684 703,085–1,678,284 195 57% 

Dicyclomine HCl 290 1,188,897 669,792–1,708,001 339 99% 

Nph, human insulin isophane 228 1,176,930 617,196–1,736,663 341 100% 

Losartan/hydrochlorothiazide 263 1,176,050 755,814–1,596,286 341 100% 

Metoclopramide HCl 296 1,167,293 728,971–1,605,615 341 100% 

Methocarbamol 297 1,140,023 818,332–1,461,714 187 55% 

Finasteride 197 1,134,898 652,093–1,617,704 341 100% 

Lactulose 323 1,134,620 627,955–1,641,286 341 100% 

Tolterodine tartrate 272 1,129,540 738,696–1,520,385 320 94% 

Carbidopa/levodopa 345 1,121,177 715,869–1,526,485 341 100% 

Bimatoprost 206 1,094,783 676,449–1,513,117 298 87% 

Budesonide/formoterol 

fumarate 

240 1,086,250 644,063–1,528,437 285 84% 

Nystatin 330 1,084,400 818,338–1,350,463 341 100% 

Doxycycline hyclate 361 1,082,007 834,313–1,329,702 341 100% 

Methadone HCl 230 1,080,920 418,188–1,743,653 337 99% 

Triamcinolone acetonide 327 1,076,999 882,920–1,271,077 341 100% 

Glyburide/metformin HCl 205 1,063,514 723,157–1,403,871 210 62% 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

Page 23 – Andrew M. Slavitt 

continued on next page 

Table B-1: 200 Drugs With the Highest Utilization by Dual Eligibles, continued 

Generic Name Sample 

Size* 

Projected 

Drugs* 

95-Percent Confidence 

Interval* 

Number of 

Formularies 

Including 

Percentage of 

Formularies 

Including 

Ramipril 187 1,036,844 646,839–1,426,849 339 99% 

Brimonidine tartrate 233 1,003,480 659,803–1,347,156 341 100% 

Omega-3 acid ethyl esters 224 999,736 606,370–1,393,102 339 99% 

Estrogens, conjugated 208 984,811 642,302–1,327,320 324 95% 

Mometasone furoate 247 972,134 684,519–1,259,748 340 100% 

Amlodipine 

besylate/benazepril 

228 959,920 603,084–1,316,756 325 95% 

Niacin 284 950,310 593,958–1,306,662 338 99% 

Folic acid 234 917,230 579,814–1,254,647 

Diazepam 242 914,849 602,056–1,227,643 341 100% 

Risedronate sodium 177 909,354 496,506–1,322,202 262 77% 

Solifenacin succinate 212 905,807 544,630–1,266,985 261 77% 

Hum insulin nph/reg insulin 

hm 

277 891,664 585,937–1,197,392 341 100% 

Insulin lispro 204 886,766 488,887–1,284,646 255 75% 

Fluconazole 244 876,604 629,792–1,123,416 341 100% 

Megestrol acetate 190 860,802 550,566–1,171,039 341 100% 

Olopatadine HCl 233 856,208 531,929–1,180,487 297 87% 

Amoxicillin/potassium clav 249 842,524 675,798–1,009,249 341 100% 

Ergocalciferol (vitamin D2) 246 840,670 572,795–1,108,546 

Metolazone 175 821,115 473,109–1,169,121 337 99% 

Ibandronate sodium 180 811,781 469,371–1,154,191 319 94% 

Clozapine 258 810,313 187,555–1,433,071 341 100% 

Insulin detemir 219 791,709 502,659–1,080,758 289 85% 

Timolol maleate 171 791,425 446,936–1,135,915 341 100% 

Fenofibrate 217 789,433 472,615–1,106,252 340 100% 

Estradiol 139 779,861 406,740–1,152,981 341 100% 

Quinapril HCl 166 767,100 405,556–1,128,644 338 99% 

Dutasteride 144 766,689 374,966–1,158,412 306 90% 

Nitrofurantoin monohyd/ 

m-cryst 

211 754,425 528,967–979,883 326 96% 

Terazosin HCl 182 749,047 398,590–1,099,504 341 100% 

Calcitriol 174 742,544 394,387–1,090,700 341 100% 

Amiodarone HCl 159 726,161 428,049–1,024,273 341 100% 

Fenofibric acid (choline) 183 697,843 242,136–1,153,549 274 80% 

Temazepam 183 696,803 364,561–1,029,045 259 76% 

Olmesartan medoxomil 133 691,273 352,024–1,030,523 269 79% 

Cinacalcet HCl 204 689,875 378,315–1,001,435 341 100% 

Ziprasidone HCl 335 685,268 386,358–984,178 341 100% 

continued on next page 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

Page 24 – Andrew M. Slavitt 

Table B-1: 200 Drugs With the Highest Utilization by Dual Eligibles, continued 

Generic Name Sample 

Size* 

Projected 

Drugs* 

95-Percent Confidence 

Interval* 

Number of 

Formularies 

Including 

Percentage of 

Formularies 

Including 

Estrogen,con/m-progest acet 89 680,598 163,753–1,197,443 201 59% 

Hydroxyzine pamoate 176 673,614 299,916–1,047,312 155 45% 

Prednisolone acetate 148 647,730 466,124–829,336 301 88% 

Clotrimazole/betamethasone 

dip 

170 645,039 374,168–915,909 284 83% 

Darifenacin hydrobromide 167 643,527 364,924–922,130 113 33% 

Hydrocortisone 152 613,981 360,669–867,293 341 100% 

Ketoconazole 175 609,470 407,703–811,237 341 100% 

Mycophenolate mofetil 184 603,446 282,168–924,724 341 100% 

Hydroxychloroquine sulfate 112 602,009 406,799–797,218 341 100% 

Haloperidol 261 594,843 343,034–846,652 341 100% 

Sevelamer carbonate 157 592,190 348,152–836,228 316 93% 

Cyclosporine 157 589,434 314,216–864,653 341 100% 

Isosorbide dinitrate 121 578,099 267,561–888,636 341 100% 

Doxepin HCl 169 578,028 275,021–881,036 341 100% 

Bumetanide 115 574,123 220,061–928,186 341 100% 

Mupirocin 166 559,222 377,854–740,591 341 100% 

Labetalol HCl 146 559,195 303,504–814,886 341 100% 

Albuterol 131 553,548 388,411–718,684 

Theophylline anhydrous 137 552,738 232,889–872,588 341 100% 

Source: OIG analysis of drugs commonly used by dual eligibles, 2015. 

*Sample is from the 2011 MCBS. Projections and confidence intervals are derived from its survey methodology. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

Page 25 – Andrew M. Slavitt 

APPENDIX C 

Four Drugs Commonly Used by Dual Eligibles and Not Covered Under Part D 

Generic Name Reason Excluded Under Part D 

Albuterol* No longer prescribed without 

sulfate 

Fexofenadine HCl* Nonprescription drug 

Folic acid* Vitamin or mineral product 

Ergocalciferol (Vitamin D2)* Vitamin or mineral product 

Source: OIG analysis of formulary inclusion of drugs commonly used by dual eligibles, 2015. 

*These drugs were also on the 2014 report’s list of drugs commonly used by dual eligibles 

and not covered under Part D. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Page 26 – Andrew M. Slavitt 

APPENDIX D 

Formulary Inclusion of Stand-Alone Prescription Drug Plans* and Medicare 

Advantage Prescription Drug Plans**, by Region 

Table D-1: PDP Formularies’ Inclusion of Commonly Used Drugs, by Region 

PDP 

Region State(s) Number of PDPs 

Average Rate of 

Inclusion by Formularies Minimum Rate Maximum Rate 

1 Maine, New Hampshire 27 94% 89% 99% 

2 Connecticut, Massachusetts, 

Rhode Island, Vermont 

26 94% 89% 98% 

3 New York 24 94% 89% 98% 

4 New Jersey 28 94% 89% 99% 

5 Delaware, the District of 

Columbia, Maryland 

26 94% 89% 99% 

6 Pennsylvania, West Virginia 26 94% 89% 100% 

7 Virginia 30 94% 89% 99% 

8 North Carolina 28 94% 89% 99% 

9 South Carolina 30 95% 89% 99% 

10 Georgia 29 94% 89% 99% 

11 Florida 26 94% 89% 98% 

12 Alabama, Tennessee 29 94% 89% 99% 

13 Michigan 30 94% 89% 99% 

14 Ohio 30 94% 89% 99% 

15 Indiana, Kentucky 30 94% 89% 99% 

16 Wisconsin 28 94% 89% 99% 

17 Illinois 32 94% 88% 99% 

18 Missouri 30 94% 89% 99% 

19 Arkansas 28 95% 89% 99% 

20 Mississippi 27 94% 89% 99% 

21 Louisiana 27 94% 89% 99% 

22 Texas 31 94% 89% 99% 

23 Oklahoma 30 94% 89% 99% 

24 Kansas 28 94% 89% 99% 

25 

Iowa, Minnesota, Montana, 

Nebraska, North Dakota, South 

Dakota, Wyoming 

29 94% 89% 99% 

26 New Mexico 30 94% 89% 99% 

27 Colorado 29 94% 89% 99% 

28 Arizona 29 94% 89% 99% 

29 Nevada 31 94% 89% 99% 

30 Oregon, Washington 29 94% 89% 99% 

31 Idaho, Utah 30 94% 89% 99% 

32 California 31 94% 89% 99% 

33 Hawaii 24 94% 89% 99% 

34 Alaska 23 94% 89% 99% 

Source: OIG analysis of formularies’ inclusion of drugs commonly used by dual eligibles, 2015. 

*PDP. 

**MA-PD. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Page 27 – Andrew M. Slavitt 

Table D-2: MA-PD Formularies’ Inclusion of Commonly Used Drugs, by Region 

MA-PD 

Region*** State(s) Number of MA-PDs 

Average Rate of 

Inclusion by 

Formularies 

Minimum Rate Maximum Rate 

1 Maine, New Hampshire 37 95% 89% 100% 

2 Connecticut, Massachusetts, Rhode 

Island, Vermont 

85 96% 90% 100% 

3 New York 187 95% 90% 99% 

4 New Jersey 37 94% 89% 98% 

5 Delaware, the District of Columbia, 

Maryland 

25 95% 91% 100% 

6 Pennsylvania, West Virginia 129 96% 90% 100% 

7 North Carolina, Virginia 107 96% 89% 100% 

8 Georgia, South Carolina 62 96% 89% 100% 

9 Florida 219 96% 89% 100% 

10 Alabama, Tennessee 83 96% 92% 98% 

11 Michigan 61 96% 90% 100% 

12 Ohio 91 95% 89% 100% 

13 Indiana, Kentucky 79 96% 89% 98% 

14 Illinois, Wisconsin 124 96% 86% 100% 

15 Arkansas, Missouri 70 96% 89% 99% 

16 Louisiana, Mississippi 62 96% 93% 98% 

17 Texas 128 95% 89% 99% 

18 Kansas, Oklahoma 49 96% 89% 98% 

19 

Iowa, Minnesota, Montana, Nebraska, 

North Dakota, South Dakota, 

Wyoming 

79 96% 88% 100% 

20 Colorado, New Mexico 66 97% 89% 100% 

21 Arizona 72 96% 89% 99% 

22 Nevada 30 95% 89% 99% 

23 Idaho, Oregon, Utah, Washington 157 96% 88% 100% 

24 California 283 95% 89% 100% 

25 Hawaii 17 97% 94% 100% 

Source: OIG analysis of formularies’ inclusion of drugs commonly used by dual eligibles, 2015. 

***Region 26, which covers Alaska, had no MA-PDs available for 2015. 

Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2015 (OEI-05-15-00120)