U.S. Department of Health and Human Services 
Office of Inspector General 
 
 
The Consistently Low 
Percentage of Medicare 
Enrollees Receiving 
Medication to Treat Their 
Opioid Use Disorder Remains 
a Concern  
 
Ann Maxwell  
Deputy Inspector General 
   for Evaluation and Inspections 
December 2023, OEI-02-23-00250  U.S. Department of Health and Human Services 
O  ffice of Inspector General 
 
Data Brief 
 
D  ecember 2023, OEI-02-23-00250 
 
The Consistently Low Percentage of Medicare Enrollees Receiving 
Medication to Treat Their Opioid Use Disorder Remains a Concern 
Why OIG Did This Review 
Key Results 
Opioid-related overdose deaths remain near all-time highs.  In 2022, 
Medicare enrollees continue to  there were an estimated 83,827 opioid-related overdose deaths in 
face challenges accessing  the United States.1  Most of these deaths involved synthetic opioids, 
medication to treat their opioid  such as illicit fentanyl.2  As such, the Office of Inspector General 
use disorder, with certain groups  (OIG) continues to monitor access to treatment for opioid use 
of enrollees facing even greater 
disorder and the opioid overdose-reversal drug naloxoneboth of 
challenges than others. 
which can save lives.   
Yet, for the first time, more than 
This data brief is a part of a series, released annually by OIG since 
600,000 enrollees received 
naloxonethe opioid overdose- 2017, that monitors indicators of the opioid epidemic in Medicare.  
reversal drugthrough Medicare  It provides the most updated information on the number of 
Part D, an important step toward  enrollees experiencing opioid overdoses and the number receiving 
reducing overdose-related  medication for opioid use disorder and overdose-reversal 
deaths.  medications.  It also monitors the use of prescription opioids and 
questionable prescribing in Part D.3    
What OIG Found  
About 52,000 people enrolled in Medicare experienced an opioid overdose during 2022.  The exact 
number is likely higher, as additional enrollees may have overdosed who did not receive medical care 
billed to Medicare.  Further, of the about 1.1 million enrollees who have opioid use disorder, just 
18 percent received medication to treat their disorder.4  This low percentage highlights that enrollees 
are continuing to face challenges accessing treatment.  In some States, the percentage of enrollees 
receiving treatment for their opioid use disorder was far lower than that for the Nation, with just 
6 percent receiving medication in Florida.  In addition, certain groups of enrolleesincluding those 
without the low-income subsidywere less likely than others to receive medication.  There are also 
notable disparities by race and ethnicity in those receiving medication.   
On the other hand, the number of Part D enrollees receiving the opioid overdose-reversal drug 
naloxone grew to more than 600,000an all-time high.  Although reaching this high number is an 
important step toward reducing overdose-related deaths, there is also new concern.  In 2023, Narcan
a brand-name naloxonebecame available over-the-counter.  Because of Narcans change from 
prescription to over-the-counter status, manufacturers of generic equivalents of Narcani.e., 4 mg 
naloxone nasal spraysmust also now change their products to over-the-counter status.  As a result, 
Narcan and its generic equivalents will no longer be covered by Medicare Part D.  Without Part D 
coverage, enrollees will likely face higher out-of-pocket costs, which may create access barriers.      
In addition, we found that key indicators of misuse or diversion of prescription opioids in Part D 
continue to decline.  The number of Medicare enrollees who received high amounts of prescription 
  opioids decreased from prior years, as did the number who received extreme amounts of opioids or 
who appear to be doctor shopping.  Further, the number of prescribers with questionable prescribing 
remained about 100, similar to that for the prior 2 years. 
What OIG Recommends 
As the opioid epidemic continues to take tens of thousands of lives each year, it is essential that the 
Centers for Medicare & Medicaid Services (CMS) and the Department continue to work to ensure 
access to medication to treat opioid use disorder and opioid overdose-reversal drugs.  CMS and the 
Department have taken a number of actions to increase access to medication for opioid use disorder.  
However, the low percentage of enrollees receiving medication to treat their opioid use disorder calls 
for additional action.   
OIG has made several recommendations to CMS in previous studies related to treatment.  Notably, to 
encourage providers to treat more Part D enrollees who have opioid use disorder, OIG recommended 
that CMS inform providers about the use of buprenorphinea common medication to treat opioid use 
disorderand the low risk of diversion of this medication in Medicare.5  CMS should continue its efforts 
to implement these and other recommendations and to identify additional ways to improve access to 
medication to treat opioid use disorder for all Medicare enrollees who need it.   
Further, as part of this data brief, OIG recommends that CMS educate enrollees and providers about 
options for access to overdose-reversal medications, as Narcan and its generic equivalents will no 
longer be covered by Part D.  Depending on the enrollees circumstances, these options may include 
receiving coverage of over-the-counter naloxone through certain States Medicaid programs (if dually 
eligible).  CMS concurred with our recommendation. 
 
 
  FINDINGS 
Opioid overdoses remain a concern; about 52,000 people 
enrolled in Medicare Part D experienced an overdose in 2022 
In 2022, at least 51,864 people enrolled in Medicare Part D had an opioid overdose.  
This is the number of Part D enrollees who received medical care for an opioid 
overdose, such as an emergency room visit, that was billed to Medicare.6  These 
overdoses represent non-fatal and fatal events.  As mentioned, most fatal opioid-
related overdoses nationwide involve synthetic opioids, such as illicit fentanyl.7 
The total number of enrollees who had an opioid overdose is likely higher, given that 
enrollees who had an overdose and did not receive medical care billed to Medicare 
are not captured in this analysis.8   
Fewer than 1 in 5 Medicare enrollees with opioid use disorder 
received medication to treat their disorder 
Opioid use disorder is a problematic pattern of opioid use that leads to clinically 
significant impairment or distress.9  It is a chronic condition that can be treated with 
certain medications that have been 
shown to decrease illicit opioid use and  Exhibit 1: About 18 percent of 
opioid-related overdose deaths.  In  enrollees with opioid use disorder 
2022, about 1.1 million people enrolled  received medication to treat this 
in Medicare had a diagnosis of opioid 
condition through Medicare. 
use disorder.10  See Appendix A for 
information about this group of 
enrollees. 
Overall, just 18 percent of 
Medicare enrollees received 
medication to treat their 
opioid use disorder in 2022 
Medications to treat opioid use disorder 
have been shown to decrease illicit 
Source: OIG analysis of Medicare claims data, 2023. 
opioid use and opioid-related overdose 
deaths.  Yet, just 210,771 of the about 1.1 million Medicare enrollees with opioid use 
disorderslightly more than 18 percentreceived medication for this disorder in 
2022.11  See Exhibit 1. 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 4  Each of these 210,771 enrollees received at least one of three approved drugs to treat 
opioid use disorder: buprenorphine, methadone, and naltrexone.12  These medications 
are sometimes referred to as medications for opioid use disorder (MOUD). 
The overall proportion of enrollees with opioid use disorder receiving medication 
remained about the same as in 2021.13  This low proportion continues to raise 
concern.  It may indicate that enrollees are facing ongoing challenges accessing 
treatment. 
These challenges may be due to a variety of reasons, including difficulties accessing 
providers who can prescribe medication.  They may also be, in part, due to stigma 
surrounding both opioid use disorder and its treatment. 14  This stigma may make it 
less likely for individuals to seek treatment and for providers to choose to provide 
treatment.  
Enrollees most commonly received buprenorphine in office-based settings. 
In 2022, 13 percent (145,054) of the about 1.1 million Medicare enrollees with opioid 
use disorder received buprenorphine.15  The vast majority of these enrollees received 
buprenorphine in office-based settings, while a small number received it in opioid 
treatment programs.16  See Exhibit 2. 
Until late 2022, prescribers were required to obtain a waiver from the Substance 
Abuse and Mental Health Administration (SAMHSA) to prescribe or administer 
buprenorphine in office-based settings and were limited in the number of patients 
they could treat.17  As a result, enrollees may have had more limited access to 
providers. 
Exhibit 2: Most Medicare enrollees receiving medication for opioid use 
disorder received buprenorphine in an office-based setting. 
Proportion of the 1.1 Million Medicare Enrollees With Opioid Use 
Disorder by Medication and Setting 
Office Based  Opioid Treatment Program  Total* 
Buprenorphine  12%  <1%  13% 
Methadone  -  5%  5% 
Naltrexone  <1%  <1%  <1% 
  Total*  13%  6%  18% 
*Percentages do not sum to totals because of rounding, some enrollees received multiple medications,
and some enrollees received medication from both settings.
Source: OIG analysis of Medicare data, 2023.
Less commonly, enrollees received methadone from opioid treatment programs.  
In 2022, about 5 percent (62,020) of the about 1.1 million Medicare enrollees with 
opioid use disorder received methadone.  All of these enrollees received methadone 
through opioid treatment programs.  Under Federal law, only opioid treatment 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 5  programs are allowed to administer or dispense methadone for the treatment of 
opioid use disorder.18 
The lower proportion of enrollees receiving methadone may indicate that enrollees 
are facing barriers to accessing opioid treatment programs.  Patients typically go in 
person each day to opioid treatment programs to receive their dose of methadone.19  
The need to travel to opioid treatment programs, which can be burdensome, may 
hinder access.20  Furthermore, more stigma is attached to opioid treatment programs 
and the use of methadone than to the use of buprenorphine, and this stigma may 
impact the likelihood that patients will seek treatment.21 
A small number of enrollees received naltrexone.  Among the about 1.1 million 
Medicare enrollees with opioid use disorder, less than one percent (9,038) of enrollees 
received naltrexone in 2022.  Naltrexone is a third medication indicated for the 
treatment of opioid use disorder and requires abstinence from opioids for 7 to 
14 days before initiation.22 
In some States, the percentage of enrollees who received 
medication for their opioid use disorder was far lower than that 
for the Nation, with just 6 percent receiving medication in 
Florida  
In Florida, Texas, Kansas, and Nevada, fewer than 10 percent of enrollees received 
medication to treat their opioid use disorder, compared to 18 percent of enrollees 
nationwide.  See Exhibit 3. 
Among the States, Florida had the lowest percentage of enrollees receiving 
medication to treat their opioid use disorder, with just 6 percent of enrollees receiving 
medication.  The low percentage in Florida is particularly concerning, as Florida has 
the highest number of enrollees with opioid use disorder in the Nation.  A total of 
160,586 Medicare enrollees (14 percent of the about 1.1 million) with opioid use 
disorder live in Florida. 
Texas and Nevada had the second and third lowest percentages of enrollees receiving 
medication, at 8 percent each.  Kansas also had a low percentage (9 percent).  
See Exhibit 3 and Appendix B. 
 
 
 
 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 6  Exhibit 3: Less than 10 percent of Medicare enrollees in Florida, Texas, Nevada, and 
Kansas received medication for their opioid use disorder. 
Source: OIG analysis of Medicare claims data, 2023. 
Certain groups of Medicare enrollees were less likely than 
others to receive medication to treat their opioid use disorder 
Certain groups of enrolleesincluding those who did not receive the low-income 
subsidy, those over the age of 65, and female enrolleeswere less likely than other 
groups to receive treatment.   
Enrollees without the Part D low-income subsidy were far less 
likely than those with the subsidy to receive medication to treat 
their opioid use disorder  
The Part D low-income subsidyalso known as Extra Helpis available to some 
enrollees who have limited income and assets.23  It provides assistance with paying for 
Part D premiums and cost-sharing. 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 7  In 2022, 9 percent of enrollees without the subsidy received medication for opioid use 
disorder, compared to 26 percent of enrollees with the subsidy.  This represents a 
nearly 3-fold difference.  See Exhibit 4. 
Exhibit 4: Medicare enrollees without the Part D low-income subsidy were 
almost 3 times less likely to receive medication for their opioid use disorder 
than were those with the subsidy. 
 
Source: OIG analysis of Medicare claims data, 2023. 
Of note, enrollees without the subsidy were less likely to receive medication to treat 
their opioid use disorder than enrollees with the subsidy regardless of their race and 
ethnicity; age group; or sex. 
Enrollees without the low-income subsidy generally pay higher cost-sharing for 
medication than those with the subsidy.  On average, enrollees without the subsidy 
paid $268 annually for Part D cost-sharing for medications for opioid use disorder in 
2022.  In contrast, enrollees with the subsidy paid an average of $19 annually in cost-
sharing for these medications in 2022.24 
Older enrollees were much less likely than younger enrollees to 
receive medication to treat their opioid use disorder  
Older enrolleesi.e., those aged 65 and abovewere less likely to receive medication 
to treat their opioid use disorder than were those under the age of 65.  Of note, 
enrollees under 65who often qualify for Medicare due to disabilityaccount for 
40 percent of enrollees with opioid use disorder.25 
In 2022, 11 percent of older enrollees received medication to treat their opioid use 
disorder, compared to 29 percent of those under 65about a 2.5-fold difference.  
See Exhibit 5. 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 8  Exhibit 5: Medicare enrollees aged 65 and above were about 2.5 times less 
likely to receive medication for their opioid use disorder than were those 
under 65. 
 
Source: OIG analysis of Medicare claims data, 2023. 
Older enrollees were less likely to receive medication for opioid use disorder than 
were enrollees under 65, regardless of their race and ethnicity; low-income subsidy 
status; or sex. 
Female enrollees were less likely than male enrollees to receive 
medication to treat their opioid use disorder  
In 2022, 15 percent of female and 23 percent of male enrollees received medication 
to treat their opioid use disorder.   
Female enrollees were less likely to receive medication regardless of their race and 
ethnicity; low-income subsidy status; or age group. 
There also are notable disparities by race and ethnicity in those 
who received medication for opioid use disorder through 
Medicare  
There are differences by race and ethnicity in the percentage of Medicare enrollees 
who received medication to treat their opioid use disorder.26  Eleven percent of 
Asian/Pacific Islander, 15 percent of Black, 15 percent of Hispanic, and 19 percent of 
White enrollees received medication to treat their opioid use disorder in 2022.  See 
Exhibit 6.  
 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 9  Exhibit 6: About 15 percent or less of Asian/Pacific Islander, Black, and 
Hispanic Medicare enrollees received medication to treat their opioid use 
disorder. 
 
Source: OIG analysis of Medicare claims data, 2023.   
Asian/Pacific Islander, Black, and Hispanic enrollees were less likely than White 
enrollees to receive medication to treat their opioid use disorder, regardless of their 
low-income subsidy status or sex.27   
Of note, Hispanic and Asian/Pacific Islander enrollees without the Part D low-income 
subsidy had particularly low likelihoods of receiving medication, with just 6 percent of 
each group receiving medication.   
There were also differences in the settings in which enrollees 
received medication to treat their opioid use disorder  
While Black and Hispanic enrollees were less likely overall to receive medication to 
treat their opioid use disorder, they were more likely than other enrollees to receive 
methadone at opioid treatment programs.  
About 7 percent of Hispanic and of Black enrollees received methadone to treat their 
opioid use disorder.  These enrollees account for about half of all Hispanic and half of 
all Black enrollees who received medication.  See Exhibit 7. 
Typically, patients who receive methadone must travel each day to opioid treatment 
programs to receive their doses.28  In contrast, buprenorphine and naltrexone can be 
prescribed in office-based settings and dispensed by pharmacies, making them more 
convenient than methadone.29  In addition, as previously mentioned, methadone 
generally has more stigma attached to it than does buprenorphine or naltrexone.30    
 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 10  Exhibit 7: Black and Hispanic enrollees were more likely to receive 
methadonewhich is only available at opioid treatment programsthan 
were Asian/Pacific Islander and White enrollees. 
Source: OIG analysis of Medicare claims data, 2023.   
The number of enrollees who received prescriptions for the 
overdose-reversal drug naloxone increased substantially, to an 
all-time high of more than 600,000 enrollees  
The number of enrollees who received naloxone prescriptions through Part D grew in 
2022, continuing an upward trend that has occurred in every recent year other than 
2020.   
Naloxone is a medication that can reverse the effects of an opioid overdose.  
Overdoses occur when high doses of opioidsalone or in combination with other 
substancescause breathing to slow to dangerous levels or to stop altogether.  
When naloxone (such as the brand-name drug Narcan) is administered in a timely 
fashion, it can save lives by blocking the effects of opioids and restoring normal 
breathing.31 
A total of 607,794 enrollees received naloxone through Part D in 2022, compared to 
445,562 enrollees in 2021.32  See Exhibit 8.  This represents a 36-percent increase in 
the number of enrollees receiving naloxone.33  The growth in the number of Medicare 
enrollees receiving naloxone is an important step forward in addressing the opioid 
crisis.  
The most commonly dispensed versions of naloxone were the brand-name drug 
Narcan and its generic equivalents (i.e., 4 mg naloxone nasal sprays).  About 
96 percent of the naloxone dispensed through Part D in 2022 was Narcan or a generic 
equivalent.34   
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 11  Exhibit 8: The number of enrollees receiving naloxone through Part D 
increased significantly in 2022. 
 
Source: OIG analysis of Medicare data, 2023. 
Enrollees will likely face higher out-of-pocket costs for Narcan, as 
it is now available over-the-counter  
Narcan became available over-the-counter in September 2023.  As a result, Narcan 
will no longer be considered a prescription medication and, therefore, will no longer 
be covered by Medicare Part D.35  Federal law prohibits Medicare Part D from 
covering over-the-counter medications under most circumstances.36  
Narcans change to over-the-counter status will also impact generic equivalents of 
Narcani.e., other 4 mg naloxone nasal spray products.  Manufacturers of these 
products will now be required to submit a supplement to their applications to the 
Food and Drug Administration (FDA) to effectively change their products to over-the-
counter status.37  This means that, after a period of transition, generic 4 mg naloxone 
nasal spray will also no longer be covered by Part D.38  
Without Part D coverage, enrollees will likely face higher out-of-pocket costs for 
Narcan because they will pay the full cost of the medication rather than a portion of 
the cost (e.g., cost-sharing).  Higher out-of-pocket cost may create access barriers for 
some enrollees, particularly those who receive the low-income subsidy.  Enrollees with 
the low-income subsidy paid an average of about $2 in cost-sharing for Narcan and 
its generic equivalents in 2022, while other enrollees paid an average of $29.  In 
contrast, Narcans manufacturer stated that its suggested price for over-the-counter 
Narcan is $44.99.39  
For enrollees facing higher out-of-pocket costs and potential access barriers for over-
the-counter Narcan or its generic equivalents, there may be alternatives depending 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 12  on the enrollees circumstances.  For example, some enrollees may have coverage of 
over-the-counter naloxone through their Medicare Advantage plan.  CMS has 
encouraged Medicare Advantage plans to cover over-the-counter naloxone under 
their Medicare Advantage supplemental benefits.40  However, taking this action is 
optional for plans and would only impact those enrolled in Medicare Advantage plans 
that opt to offer this benefit.  In addition, dually eligible Medicare enrollees (i.e., those 
who are enrolled in Medicaid and Medicare) may have the cost of over-the-counter 
naloxone covered by Medicaid, depending on their State.41  Alternatively, otherless 
commonformulations and dosages of naloxone, such as injectable naloxone, will 
remain prescription drugs and continue to be covered by Part D.  In addition, a 
different opioid overdose-reversal medicationa nalmefene nasal spraywas 
recently approved by FDA as a prescription drug.42  Ensuring that Medicare enrollees 
and their providers know about covered and over-the-counter options is critical, 
given the extent of the opioid crisis.     
Indicators of misuse and diversion of prescription opioids in 
Part D continue to decline 
OIG has been monitoring opioid prescribing in Medicare Part D since 2017, looking 
for patterns that may indicate misuse or diversion that warrant further scrutiny.  The 
number of concerning patterns has declined over time with new lows in key areas in 
2022.    
About 176,000 people enrolled in Part D received high amounts 
of prescription opioids in 2022, fewer than in prior years  
In 2022, a total of 176,021 enrollees received high amounts of opioids through 
Part Di.e., each enrollee had an average morphine equivalent dose (MED) of greater 
than 120 mg a day for at least 3 months.  MED is a measure that converts all the 
various opioids and strengths into one standard value.  These enrollees did not have 
cancer and were not in hospice care.  Although enrollees may receive opioids for 
legitimate purposes, these amounts raise concern as opioids carry a number of health 
risks.43   
The number of enrollees receiving high amounts of opioids is a decrease from 2021, 
when 199,169 enrollees received high amounts.  It is also a decline from previous 
years.  In 2016, when OIG first began measuring this number, a total of 
501,008 enrollees received these high amounts.  (See Appendix C for more 
information about previous years.) 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 13  Just under 20,000 people enrolled in Part D received extreme 
amounts of prescription opioids or appeared to be doctor 
shopping, also a decline from prior years 
Two subgroups of enrollees in particular are at serious risk from prescription opioids: 
(1) enrollees who receive extreme amounts of opioids and (2) enrollees who appear to 
be doctor shopping.  This does not include enrollees who had cancer or were in 
hospice care.  Other Part D enrollees may also be at serious risk but do not fall into 
either group. 
A total of 19,936 enrollees were in these two subgroups.  Specifically, 18,426 enrollees 
received extreme amounts of opioids (i.e., had an average daily MED greater than 
240 mg for 12 months) and 1,626 enrollees appeared to be doctor shopping (i.e., 
received high amounts of opioids and had 4 or more prescribers and 4 or more 
pharmacies).  A total of 116 enrollees were in both groups. 
The number of enrollees at serious risk in 2022 (19,936 enrollees) represents a 14-
percent decline from 2021 and a 78-percent decline from 2016.44   
While the number of enrollees at serious risk from prescription opioids has declined 
substantially, these patterns still raise concern when they are observed.  They may 
signal that an enrollees care is not being monitored or coordinated properly or that 
an enrollees care needs to be reassessed.  Alternatively, they may indicate that the 
prescribers and pharmacies are not checking an enrollees opioid history before 
prescribing.45  They may also indicate that an enrollee is seeking medically 
unnecessary drugsperhaps to use them recreationally or to divert themor that an 
enrollee has an opioid use disorder and is at risk of overdose.   
About 100 prescribers had questionable opioid prescribing for 
Part D enrollees at serious risk, similar to the number in 2021  
A total of 23,925 prescribers ordered opioids for at least 1 enrollee at serious risk of 
opioid misuse or overdose (i.e., an enrollee who received extreme amounts of opioids 
or appeared to be doctor shopping) in 2022.  The vast majority of these prescribers 
ordered opioids for only one or two of these enrollees.  However, some prescribers 
ordered for many more. 
A total of 101 prescribers stand out as having questionable prescribing; they were far 
outside the norm with their prescribing and warrant further scrutiny.  They ordered 
opioids for the highest numbers of enrollees at serious risk.46  In total, these 
101 prescribers ordered 43,871 opioid prescriptionstotaling almost $15 million of 
Part D costsfor enrollees at serious risk in 2022. 
The number of prescribers with questionable prescribing for enrollees at serious risk is 
similar to that for 2021, when 98 prescribers had questionable prescribing.  It also 
represents a decline of 75 percent since 2016.47 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 14  Although opioids may be necessary for some patients, prescribing to an unusually 
high number of enrollees at serious risk raises concerns.  It may indicate that enrollees 
are receiving poorly coordinated care and could be in danger of overdose or 
dependence.  It may also signal that prescribers are not checking State prescription 
drug monitoring databases.  It may also indicate that the prescriber is ordering 
medically unnecessary drugs that could be diverted for resale or recreational use.  
Another possibility is that the prescribers identification has been sold or stolen and is 
being used for illegal purposes.  
While concerns about opioid prescribing have declined, it remains important that 
opioids be prescribed only when medically necessary and that, when identified, 
questionable prescribing patterns be addressed. 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Findings | 15  RECOMMENDATION  
As the opioid epidemic continues to take tens of thousands of lives each year, it is 
essential that CMS and the Department continue to work to ensure access to 
medication for opioid use disorder and to opioid overdose-reversal drugs.   
This data brief finds that Medicare enrollees continue to face challenges accessing 
medication to treat their opioid use disorder, with some groups of enrollees facing 
even greater challenges than other groups.  Yet, for the first time, more than 
600,000 enrollees received naloxonethe opioid overdose-reversal drugthrough 
Medicare Part D, an important step in addressing the opioid crisis.  The findings also 
demonstrate that concerns about misuse and diversion of prescription opioids 
continue to lessen.   
CMS, the Department, and Congress have taken a number of actions to increase 
access to medication for opioid use disorder.  In late December 2022, legislation lifted 
certain Federal restrictions on the prescribing of buprenorphine, the most common 
medication to treat opioid use disorder.48  In addition, CMS took steps to increase the 
number of enrollees receiving treatment and to address disparities.  For example, 
CMS released its Behavioral Health Strategy in 2022.  Goals listed in the Behavioral 
Health Strategy include strengthening equity and quality in behavioral health care and 
improving access to substance use disorder prevention, treatment, and recovery 
services.49  
However, the low percentage of enrollees receiving medication to treat their opioid 
use disorder calls for additional action.  OIG has previously made several 
recommendations to CMS to increase access to treatment.  Notably, to encourage 
providers to treat more Part D enrollees who have opioid use disorder, OIG 
recommended that CMS inform providers about the use of buprenorphinea 
common medication to treat opioid use disorderand the low risk of diversion of this 
medication in Medicare.50  OIG has also recommended that CMS create an action plan 
and take steps to address disparities in the treatment of opioid use disorder.51  
Further, from a report examining access to treatment for opioid use disorder in 
Medicaid, OIG has recently recommended that CMS encourage and support States 
efforts to reduce barriers to medication for opioid use disorder, especially among 
groups who may be underserved.52  
OIG urges CMS to continue its efforts to implement these and other 
recommendations and to identify additional ways to improve access to medication to 
treat opioid use disorder for all Medicare enrollees who need it.  OIG will also refer 
prescribers with questionable opioid prescribing identified in this report to CMS for 
follow-up, as appropriate.   
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Recommendation | 16  In addition, we recommend that CMS:  
Educate enrollees and providers about options for access to overdose-reversal 
medications, as Narcan and its generic equivalents will no longer be covered by 
Part D 
Overdose-reversal medications save lives.  It is critical that individuals at risk of 
overdose have them on hand in the event of an emergency.  Ensuring continued 
access to these medications for Medicare enrollees is particularly important in the 
coming months when Medicare Part D will no longer cover Narcan or its generic 
equivalents.   
As noted, Medicare Part D does not cover over-the-counter medications under most 
circumstances.  As a result, enrollees will lose Part D coverage of Narcan and its 
generic equivalents after they become available over-the-counter.53  Without 
coverage, enrollees will likely have increased out-of-pocket costs which may create 
access barriers.   
For enrollees facing higher out-of-pocket costs, there may be alternatives to 
purchasing Narcan or its generic equivalents over-the-counter.  Ensuring that 
enrollees and providers know about these alternatives is critical, given the extent of 
the opioid crisis and the high number of enrolleesalmost 600,000who received 
Narcan or a generic equivalent through Part D.   
To help ensure that Medicare Part D enrollees continue to have uninterrupted access 
to opioid overdose-reversal medications, CMS should educate enrollees and providers 
about Narcan and its generic equivalents switch to over-the-counter status and the 
alternative options enrollees may have for receiving overdose-reversal medications.  
Depending on the enrollees circumstances, these options may include, for example, 
receiving coverage of over-the-counter naloxone through certain Medicare 
Advantage plans that offer it as a supplemental benefit or through certain States 
Medicaid programs (if dually eligible).  Alternatively, enrollees could talk to their 
providers about whether other formulations or dosages of naloxonethat will remain 
prescription drugsor a different overdose-reversal medication would be 
appropriate.   
To educate enrollees and providers, CMS could add information to its website and the 
Medicare & You Handbook.  It could also use its annual letter to providers to 
communicate with them about this topic.  If appropriate, CMS could also work with 
Medicare Advantage plans and State Medicaid agencies to ensure that their enrollees 
are aware of coverage options.   
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Recommendation | 17  AGENCY COMMENTS AND OIG RESPONSE  
CMS concurred with our recommendation to educate enrollees and providers about 
options for access to overdose-reversal medications, as Narcan and its generic 
equivalents will no longer be covered by Part D.  CMS stated that it will seek to 
include this information in upcoming enrollee and provider outreach to help make 
both aware of other coverage options for overdose-reversal medications that will 
continue to be available after Narcan and its generic equivalents fully transition to 
over-the-counter status and remaining inventory of products labeled as prescription 
only have been exhausted. 
The full text of CMSs comments can be found in Appendix E. 
 
 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Agency Comments and OIG Response | 18  METHODOLOGY 
We based this study primarily on five data sources: Medicare Part D Prescription Drug 
Event (PDE) records, the First Databank, the Medicare Enrollment Database, the 
National Claims History File, and Part C Encounter Data.  We also use the Center for 
Disease Control and Preventions (CDCs) Morphine Milligram Equivalent (MME) 
conversion file. 
PDE records are for prescriptions that people enrolled in Medicare received through 
Part D.  They do not include prescriptions paid for through other programs, 
prescriptions paid for in cash, or illicitly purchased drugs.  Part D sponsors submit a 
PDE record to CMS each time a drug is dispensed to an enrollee in their plans.  Each 
record contains information about the drug and enrollee, as well as the identification 
numbers for the pharmacy and the prescriber.  For the purposes of this study, we use 
the term prescription to mean one PDE record. 
To obtain descriptive information about the drugs, enrollees, and prescribers, we 
matched PDE records to data from the First Databank, the National Claims History 
File, Part C Encounter Data, and CDCs MME conversion file.  The First Databank 
contains information about each drug, such as the drug name, strength of the drug, 
and therapeutic class (e.g., an opioid).  The National Claims History File contains 
claims data from Medicare Parts A and B, including diagnosis codes and prescribed 
medications.  Part C Encounter Data contain medical claims data, including diagnosis 
codes and prescribed medications, for Medicare Advantage plan enrollees.  CDCs 
MME conversion file contains information about each opioid drugs morphine 
milligram equivalence.54 
Analysis of Opioid Overdoses 
To determine the number of people enrolled in Part D who had an opioid overdose in 
2022, we used inpatient and outpatient (including professional) claims data from the 
National Claims History File and Part C Encounter Data.  We considered an enrollee to 
have had an overdose if the enrollee had at least one claim from Medicare Part A, B, 
or C with a diagnosis of an opioid poisoning from prescription or illicit opioids in 
2022. 
Analysis of Medicare Enrollees Receiving Medication to Treat 
Their Opioid Use Disorder 
We used Medicare Parts A and B Claims Data and Part C Encounter Data to determine 
which Medicare enrollees had a diagnosis of opioid use disorder in their 2022 claims.  
We considered enrollees to have opioid use disorder if they had a diagnosis code 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Methodology | 19  categorized as opioid abuse (F11.1) or opioid dependence (F11.2) on any claim 
during 2022. 
We then determined the extent to which these enrollees received medication to treat 
their opioid use disorder in outpatient settings through Medicare in 2022. 
Prescription Drug Event Records.  We first used the PDE records to identify the 
number of enrollees who filled prescriptions for medications for opioid use disorder 
at pharmacies in 2022.  Drugs filled at pharmacies are covered by Part D.  They may 
be covered by standalone prescription drug plans (PDPs) or prescription drug plans 
that are part of Medicare Advantage plans (MA-PDs). 
Medicare Claims and Part C Encounter Data.  We then used Medicare Part B Claims 
Data and Part C Encounter Data to identify the number of enrollees who were 
prescribed medications for opioid use disorder through opioid treatment programs or 
in a providers office. 
Characteristics of Medicare Enrollees Receiving Medication to 
Treat Their Opioid Use Disorder 
We determined key characteristics of the Medicare enrollees who were less likely to 
receive medication to treat their opioid use disorder.  To do this, we used the 
Medicare Enrollment Database file. 
We first determined the percentage of enrollees in each State who received 
medication to treat their opioid use disorder.  Next, we determined each enrollees 
Part D low-income subsidy status, age, sex, and race and ethnicity.  Note that 
Medicare data combine race and ethnicity and allow for only one response.  The data 
are limited to seven options: American Indian/Alaska Native, Asian/Pacific Islander, 
Black (or African-American), Hispanic, Non-Hispanic White, Other, and Unknown.  The 
data are not further disaggregated.  Race and ethnicity information is based on data 
collected from the Social Security Administration and an algorithm developed by the 
Research Triangle Institute.  This algorithm attempts to improve the quality of the 
Social Security Administrations data by amending the race data for certain groups on 
the basis of name and geography, as well as requests made by individuals for certain 
government materials to be provided in Spanish.  Although this information is 
currently the best available for the entire Medicare enrollee population, comparisons 
to self-reported data (available in certain, limited circumstances) show that race and 
ethnicity is still misclassified for some enrollees.  Because of these limitations and 
small enrollee populations in the data, we did not provide specific data for American 
Indian/Alaska Native enrollees or enrollees with other or unknown race and ethnicity.  
Next, we determined the extent to which enrollees received medication to treat their 
opioid use disorder by these characteristics.  We also calculated the average annual 
enrollee cost-sharing for medication to treat their opioid use disorder for enrollees 
with and without the low-income subsidy. 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Methodology | 20  Analysis of Trends in Part D for Naloxone 
Next, we identified all Part D prescriptions for naloxonea drug that reverses opioid 
overdoses.  We calculated the total number of Part D enrollees who received 
naloxone and the number of prescriptions for naloxone from 2013 to 2022.  We also 
calculated the average enrollee cost-sharing per prescription by naloxone labels (i.e., 
Narcan brand and generic equivalent versions). 
Analysis of Part D Enrollees Receiving Prescription Opioids 
We determined the amount of prescription opioids that each Part D enrollee received 
in 2022.  To do this, we calculated each enrollees average daily morphine equivalent 
dose (MED).55  The MED converts opioids of different ingredients, strengths, and 
forms into morphine milligram equivalents.  It allows us to sum dosages of different 
opioids to determine an enrollees daily opioid level. 
To calculate each enrollees average daily MED, we first calculated the MED for each 
prescription (i.e., for each PDE record).56  To do this, we used the following equation: 
 
(SSSSSSSSSSSSSSh ppSSSS uuSSuuSS)(QQuuQQSSSSuuSSQQ dduuddppSSSSddSSdd)(MMMMMM ccccSSccSSSSdduuccSS ffQQccSSccSS)
MMMMMM = 
Next, we summed each enrollees MED( fMMoQQr QQedda ddcuuhpp dppassyuuSS oddf) the year based on the dates of 
service and days supply on each prescription.  We refer to this as the daily MED.  We 
excluded from this analysis enrollees who had a diagnosis of cancer or a hospice stay 
at any point in 2022.57 
We analyzed the MED data using the same criteria that we used in our previous 
annual analyses of the 2016 to 2021 data.58  We began by determining the extent to 
which enrollees received high amounts of opioids.  To do this, we calculated each 
enrollees average daily MED over each 90-day period in 2022.  We considered 
enrollees to have high amounts of opioids if they exceeded an average daily MED of 
120 mg for any 90-day period and received opioids for 90 or more days in the year. 
We then determined the extent to which these enrollees received extreme amounts of 
opioids.  We calculated each enrollees average daily MED over the entire year.  We 
considered an enrollee who exceeded an average daily MED of 240 mg for the entire 
year and had received opioids for 360 days or more to have received an extreme 
amount of opioids. 
Next, we determined the extent to which enrollees appeared to be doctor shopping.  
To do this, we calculated the total number of prescribers and pharmacies from which 
each enrollee received opioids in 2022.  We considered enrollees to have appeared to 
be doctor shopping if they exceeded an average daily MED of 120 mg for any 90-day 
period; received opioids for 90 or more days in the year; and received opioids from 
four or more prescribers and four or more pharmacies. 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Methodology | 21  Lastly, we compared the number of enrollees who received high amounts of opioids 
and the number at serious riski.e., the number who received extreme amounts of 
opioids or appeared to be doctor shoppingto the numbers of enrollees whom we 
had previously identified in our annual analyses of the 2016 to 2021 data. 
Identification of Prescribers With Questionable Prescribing  
For this analysis, we identified prescribers who ordered opioids for a high number of 
Part D enrollees at serious riski.e., enrollees who received extreme amounts of 
opioids and enrollees who appeared to be doctor shopping.  We considered these 
prescribers to have questionable prescribing patterns that warrant further scrutiny.  
We used the National Provider Identifiers (NPIs) on the PDE records to identify 
prescribers.  We considered each NPI to be a unique prescriber.59 
In total, 17,753 prescribers ordered opioids for enrollees who received extreme 
amounts of opioids and 8,261 prescribers ordered opioids for enrollees who appeared 
to be doctor shopping.  For each of these prescribers, we calculated the number of 
enrollees in each group for whom the prescriber ordered opioids.  We then identified 
the prescribers who ordered opioids for the highest number of enrollees in each 
group.  All of these prescribers are extreme outliers in terms of the number of 
enrollees to whom they prescribed opioids in one of the groups at serious risk.  
These prescribers were more than 3 standard deviations above the mean and in the 
top 0.3 percent. 
Limitations 
This analysis is based on Medicare claims data.  It is not based on a review of medical 
records.  The analysis does not include data on opioids, medications for opioid use 
disorder, or naloxone that enrollees may have received from sources other than 
Medicare.  Analysis related to race and ethnicity is based on the best available 
information; however, there are limitations to these data.  For a fuller discussion, see 
OIG, Inaccuracies in Medicare's Race and Ethnicity Data Hinder the Ability To Assess 
Health Disparities, OEI-02-21-00100, June 2022.   
Standards 
We conducted this study in accordance with the Quality Standards for Inspection and 
Evaluation issued by the Council of the Inspectors General on Integrity and Efficiency.  
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Methodology | 22  APPENDIX A 
Characteristics of Medicare Enrollees With Opioid Use Disorder 
in 2022 
People Enrolled in   Proportion of All People 
Medicare With   Enrolled in Medicare With 
  Opioid Use Disorder  Opioid Use Disorder 
All  1,147,768  100% 
 
   
Part D Low-Income Subsidy 
With  635,373  55% 
Without  512,395  45% 
Age Group     
<65  453,787  40% 
65+  693,981  60% 
Sex     
Female  642,145  56% 
Male  505,623  44% 
Race and Ethnicity*     
Asian/Pacific Islander  10,837  0.9% 
Black  172,691  15% 
Hispanic  113,775  10% 
White  823,992  72% 
     
* Because of previously identified limitations and small enrollee populations in the data, we did not provide specific data for American 
Indian/Alaska Native enrollees or enrollees with other or unknown race and ethnicity.  As a result, race and ethnicity data do not sum to 
100 percent.  
Source: OIG analysis of Medicare data, 2023. 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Appendix A | 23  APPENDIX B 
State Data about Medicare Enrollees Who Receive Medication to 
Treat Their Opioid Use Disorder, 2022 
  Number of  Percentage of    Number of  Percentage of 
Enrollees  Enrollees Who  Enrollees  Enrollees  
With Opioid  Received  With Opioid  Who Received 
Use Disorder  Medication  Use Disorder  Medication 
Florida  160,586  6%  Pennsylvania  54,641  23% 
Texas  84,566  8%  Michigan  37,611  23% 
Nevada  15,417  8%  New Mexico  10,247  23% 
Kansas  6,515  9%  Tennessee  33,386  23% 
Georgia  34,601  10%  Hawaii  2,354  23% 
Oklahoma  23,021  10%  Wyoming  795  24% 
Arizona  32,686  11%  Washington  27,355  24% 
Louisiana  25,914  12%  Montana  2,707  24% 
Iowa  5,271  12%  Oregon  16,761  24% 
Arkansas  11,430  13%  New Jersey  25,512  24% 
Idaho  7,411  13%  Virginia  20,717  25% 
Colorado  17,431  13%  Alabama  22,891  26% 
Missouri  18,461  14%  Wisconsin  11,773  27% 
California  113,984  14%  District Of Columbia  2,645  30% 
Nebraska  3,164  14%  Ohio  31,207  31% 
Delaware  6,840  15%  Connecticut  13,197  33% 
Mississippi  12,414  15%  Alaska  1,380  33% 
Utah  11,337  16%  Kentucky  22,615  33% 
Illinois  24,686  16%  New York  43,823  34% 
South Dakota  836  17%  Maryland  19,889  34% 
Nation  1,147,768  18%  West Virginia  7,871  40% 
South Carolina  15,584  19%  New Hampshire  5,476  44% 
North Dakota  1,053  19%  Maine  5,832  50% 
Indiana  24,165  20%  Rhode Island  4,025  50% 
North Carolina  39,606  20%  Massachusetts  26,732  50% 
Minnesota  13,529  21%  Vermont  2,431  60% 
Source: OIG analysis of Medicare Part D data, 2023. 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Appendix B | 24  APPENDIX C 
Prescription Opioid Use in Medicare Part D 
Exhibit C-1: About 176,000 people enrolled in Part D received high amounts of opioids 
in 2022. 
Number of People Enrolled in Part D Who  Percentage Change from  
   Received High Amounts of Opioids  Previous Year 
2016  501,008  - 
2017  458,935  -8% 
2018  353,751  -23% 
2019  266,728  -25% 
2020  225,463  -15% 
2021  199,169  -12% 
2022  176,021  -12% 
Source: OIG analysis of Medicare Part D data, 2017-2023. 
 
Exhibit C-2: Almost 20,000 people enrolled in Part D were at serious risk in 2022. 
Number of  
Enrollees  
Who   Percentage   Number of   Percentage   Total   Percentage  
Received   Change   Enrollees   Change   Number of   Change 
Extreme   from   Who   from   Enrollees   from  
Amounts of   Previous   Appear To Be   Previous   at   Previous  
   Opioids  Year  Doctor Shopping  Year  Serious Risk*  Year 
2016  69,563  -  22,308  -  89,843  - 
2017  57,611  -17%  14,814  -34%  71,260  -21% 
2018  40,374  -30%  8,796  -41%  48,558  -32% 
2019  29,734  -26%  4,346  -51%  33,809  -30% 
2020  27,325  -8%  2,131  -51%  29,306  -13% 
2021  21,493  -21%  1,805  -15%  23,186  -21% 
2022  18,426  -14%  1,626  -10%  19,936  -14% 
* Numbers in the total column do not equal the sums of the numbers in the corresponding extreme amount and doctor 
shopping columns because enrollees can be in both groups. 
Source: OIG analysis of Medicare Part D data, 2017-2023. 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Appendix C | 25  APPENDIX D 
Prescribers With Questionable Opioid Prescribing for Enrollees 
at Serious Risk 
Exhibit D: About 100 prescribers ordered opioids for a high  
number of Part D enrollees at serious risk in 2022. 
Number of Prescribers With   Percentage 
Questionable Opioid Prescribing for   Change from 
   Enrollees at Serious Risk  Previous Year 
2016  401  - 
2017  282  -30% 
2018  198  -30% 
2019  142  -28% 
2020  98  -31% 
2021  98  0% 
2022  101  3% 
For more information on OIGs previous data briefs, see OIGs featured topics page, 
Combating the Opioid Epidemic, available at https://oig.hhs.gov/reports-and-
publications/featured-topics/opioids/.  
Source: OIG analysis of Medicare Part D data, 2017-2023. 
  
 
 
 
 
 
 
 
 
 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Appendix D | 26  APPENDIX E 
Agency Comments 
Following this page are the official comments from CMS. 
   
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Appendix E | 27   
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Appendix E | 28     
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Appendix E | 29   
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Appendix E | 30  ACKNOWLEDGMENTS AND CONTACT 
Acknowledgments 
Miriam Anderson served as the team leader for this study.  Others in the Office of 
Evaluation and Inspections who conducted the study include Margaret Himmelright 
and Jason Kwong.  Office of Evaluation and Inspections headquarters staff who 
provided support include Chris Galvin, Robert Gibbons, Althea Hosein, Michael 
Novello, and Sarah Swisher.  
This report was prepared under the direction of Jodi Nudelman, Regional Inspector 
General for Evaluation and Inspections in the New York regional office, and 
Nancy Harrison and Meridith Seife, Deputy Regional Inspectors General. 
 
Contact 
To obtain additional information concerning this report, contact the Office of Public 
Affairs at Public.Affairs@oig.hhs.gov.  OIG reports and other information can be found 
on the OIG website at oig.hhs.gov. 
Office of Inspector General 
U.S. Department of Health and Human Services 
330 Independence Avenue, SW 
Washington, DC 20201 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250  Acknowledgments and Contact | 31  ENDNOTES 
 
1 CDC, Provisional Drug Overdose Death Counts, August 6, 2023.  Accessed at https://www.cdc.gov/nchs/nvss/vsrr/drug-
overdose-data.htm on August 22, 2023. 
2 In 2022, an estimated 75,811 overdose deaths in 2022 involved synthetic opioids, other than methadone, including drugs 
such as fentanyl and tramadol.  This accounted for approximately 90 percent of all opioid-related overdose deaths.  CDC, 
Provisional Drug Overdose Death Counts, August 6, 2023.  Accessed at https://www.cdc.gov/nchs/nvss/vsrr/drug-overdose-
data.htm on August 22, 2023. 
3 See OIG, Opioid Overdoses and the Limited Treatment of Opioid Use Disorder Continue To Be Concerns for Medicare 
Beneficiaries (OEI-02-22-00390) September 13, 2022.  Also see OIG, Many Medicare Beneficiaries Are Not Receiving Medication 
to Treat Their Opioid Use Disorder (OEI-02-20-00390) December 15, 2021; OIG, Concerns Persist About Opioid Overdoses and 
Medicare Beneficiaries Access to Treatment and Overdose-Reversal Drugs (OEI-02-20-00401) August 10, 2021; OIG, Opioid Use 
in Medicare Part D During the Onset of the COVID-19 Pandemic (OEI-02-20-00400) February 2, 2021; OIG, Opioid Use in 
Medicare Part D Continued To Decline in 2019, but Vigilance Is Needed as COVID-19 Raises New Concerns (OEI-02-20-00320) 
August 13, 2020; OIG, Opioid Use Decreased in Medicare Part D, While Medication-Assisted Treatment Increased (OEI-02-19-
00390) July 8, 2019; OIG, Opioid Use in Medicare Part D Remains Concerning (OEI-02-18-00220) June 17, 2018; and OIG, Opioids 
in Medicare Part D: Concerns About Extreme Use and Questionable Prescribing (OEI-02-17-00250) July 11, 2017.  Additionally, 
OIG looked at access to treatment for opioid use disorder in Medicaid.  See OIG, Many Medicaid Enrollees with Opioid Use 
Disorder Were Treated with Medication; However, Disparities Present Concerns (OEI-BL-22-00260) September 26, 2023. 
4 This represents the number of Medicare enrollees who received medication to treat their opioid use disorder in outpatient 
settings.   
5 OIG, The Risk of Misuse and Diversion of Buprenorphine for Opioid Use Disorder Appears to Be Low in Medicare Part D (OEI-02-
22-00160) April 16, 2023.  Also see OIG, The Risk of Misuse and Diversion of Buprenorphine for Opioid Use Disorder in Medicare 
Part D Continues to Appear Low: 2022 (OEI-02-24-00130) November 11, 2023. 
6 We considered an enrollee to have had an overdose if the enrollee had at least one claim from Medicare Part A, B, or C with a 
diagnosis of an opioid poisoning from prescription or illicit opioids. 
7 In 2022, an estimated 75,811 overdose deaths in 2022 involved synthetic opioids, other than methadone, including drugs 
such as fentanyl and tramadol.  This accounted for approximately 90 percent of all opioid-related overdose deaths.  CDC, 
Provisional Drug Overdose Death Counts, August 6, 2023.  Accessed at https://www.cdc.gov/nchs/nvss/vsrr/drug-overdose-
data.htm on August 22, 2023. 
8 Further, if an enrollees claim had yet to be submitted to Medicare at the time that claims data was analyzed for this report 
(July 2023), then their overdose would not be identified. 
9 Diagnostic and Statistical Manual of Mental Disorders: DSM-5.  Arlington, VA: American Psychiatric Publishing, 2013.   
10 Each of these 1.1 million Medicare enrollees had a diagnosis of opioid use disorder on at least 1 Medicare claim in 2022 or 
received at least 1 service from an opioid treatment program in 2022.  We refer to these enrollees as enrollees with opioid use 
disorder throughout the report. 
11 This analysis includes medication for opioid use disorder that enrollees received through Medicare in outpatient settings, 
including medication prescribed in office-based settings and filled at pharmacies and medication received at opioid treatment 
programs.   
12 The Food and Drug Administration (FDA) recommends that all three of these medications be available to all patients because 
certain medications may be more appropriate for some patients than others.  FDA, Information about Medication-Assisted 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250   Endnotes | 32   
Treatment (MAT), May 23, 2023.  Accessed at https://www.fda.gov/drugs/information-drug-class/information-about-
medication-assisted-treatment-mat on August 23, 2023.  
13 OIG, Opioid Overdoses and the Limited Treatment of Opioid Use Disorder Continue To Be Concerns for Medicare Beneficiaries 
(OEI-02-22-00390) September 13, 2022.  By comparison, a recent study estimated that in 2021 just over 22 percent of adults 
who reported opioid use disorder in the past year received medication to treat their opioid use disorder.  C.M. Jones, B. Han, 
G.T. Baldwin, E.B. Einstein, W.M. Compton, Use of Medication for Opioid Use Disorder Among Adults With Past-Year Opioid 
Use Disorder in the US, 2021, JAMA Netw Open. 2023;6(8):e2327488. doi:10.1001/jamanetworkopen.2023.27488.  Accessed at 
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2807964?utm_source=For_The_Media&utm_medium=referral&
utm_campaign=ftm_links&utm_term=080723 on September 20, 2023. 
14 National Institute of Drug Abuse, Words Matter  Preferred Language for Talking About Addiction.  Accessed at 
https://www.drugabuse.gov/drug-topics/addiction-science/words-matter-preferred-language-talking-about-addiction on  
June 14, 2023. 
15  Buprenorphine is a Schedule III controlled substance that suppresses opioid withdrawal symptoms by relieving cravings.  
Buprenorphine is also separately indicated for pain.  Buprenorphine products indicated for pain are different from 
buprenorphine products indicated for the treatment of opioid use disorder and are not included in this review. 
16 Most enrollees receive buprenorphine in office-based settings that is dispensed by pharmacies and covered by Medicare 
Part D.  Far less commonly, enrollees receive buprenorphine administered by a provider in an office-based setting covered 
under Medicare Part B or C.  
17 The Drug Addiction Treatment Act of 2000 (Title XXXV of the Childrens Health Act of 2000, P.L. No. 106-310) allowed 
providers to obtain a waiver to prescribe Schedule III, IV, and V drugsincluding buprenorphinefor substance use disorder 
treatment in office settings.  Section 1262 of the Consolidated Appropriations Act, 2023 (P.L. No. 117-328), removed the waiver 
requirement. 
18 21 U.S.C.  823(g)(1).  Also see 42 C.F.R.  8.11 &  8.12(h).  Because methadone can only be provided through opioid 
treatment programs and cannot be dispensed by pharmacies, it is not covered by Part D.  See also CMS, Medicare Prescription 
Drug Benefit Manual, Ch. 6, Sec. 10.8.  
19 Under certain circumstances, patients at opioid treatment programs are permitted to take home doses of both 
buprenorphine and methadone, thus alleviating the need to travel each day.  See 42 CFR  8.12(i).  During the COVID-19 Public 
Health Emergency, SAMHSA increased the flexibility in dispensing take-home doses of methadone and other opioid agonist 
medications.  See SAMHSA, Opioid Treatment Program (OTP) Guidance, March 2020.  Accessed at 
https://www.samhsa.gov/sites/default/files/otp-guidance-20200316.pdf on June 6, 2023.  In April 2023, SAMHSA temporarily 
extended flexibilities allowing unsupervised take-home medication under certain conditions until one year from the end of the 
public health emergency or until such time that the Department publishes final rules revising 42 C.F.R  8, whichever occurs 
sooner.  See SAMHSA, Methadone Take-Home Flexibilities Extension Guidance, August 2023.  Accessed at 
https://www.samhsa.gov/medications-substance-use-disorders/statutes-regulations-guidelines/methadone-guidance on 
August 24, 2023. 
20 Patients may experience difficulties accessing opioid treatment programs for other reasons, such as geographic limitations 
or patient admission requirements.  There were approximately 1,400 opioid treatment programs enrolled in Medicare in the 
United States and its territories as of April 2023, but distribution of programs is not even across the States.  See CMS, Opioid 
Treatment Program Providers, April 2023.  Accessed at https://data.cms.gov/provider-characteristics/medicare-provider-
supplier-enrollment/opioid-treatment-program-providers on April 10, 2023.  Notably, State laws related to opioid treatment 
programs differ.  For instance, some States have laws and regulations related to where opioid treatment programs can be 
located.  See J.R. Jackson, et al., Characterizing variability in state-level regulations governing opioid treatment program, 
Journal of Substance Abuse Treatment, Vol. 115, August 2020. 
21 B. Andraka-Christou, Addressing Racial and Ethnic Disparities in the Use of Medications for Opioid Use Disorder, Health 
Affairs, June 2021, Vol. 6, No. 40. 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250   Endnotes | 33   
22 The vast majority of enrollees who received naltrexone did so in office-based settings.  These drugs were dispensed by 
pharmacies and covered by Part D.  
23 42 C.F.R.  423.315(d). 
24 Part D covered medications dispensed at pharmacies generally have cost-sharing.  Medications dispensed or administered at 
opioid treatment programs do not have cost-sharing.   
25 People who qualify for Social Security Disability Insurance (SSDI) benefits are eligible for Medicare after a 24-month 
qualifying period.  For more information, see Social Security Administration (SSA), Disability Benefits | How You Qualify.  
Accessed at https://www.ssa.gov/benefits/disability/qualify.html#anchor3 on June 2, 2023.  Also see SSA, Medicare Information.  
Accessed at https://www.ssa.gov/disabilityresearch/wi/medicare.htm#general on September 1, 2023. 
26 This analysis uses the race and ethnicity information from Medicares enrollment database, which is based on data collected 
from the Social Security Administration and an algorithm.  Note that these data combine race and ethnicity and allow for only 
one response.  Although these data are the best available information on race and ethnicity for Medicare enrollees, there are 
limitations to these data.  See the methodology.  For a fuller discussion, also see OIG, Inaccuracies in Medicare's Race and 
Ethnicity Data Hinder the Ability To Assess Health Disparities (OEI-02-21-00100) June 15, 2022.   
27 Asian/Pacific Islander and Hispanic enrollees were also less likely to receive medication regardless of their age group.  
However, older Black enrolleesi.e., those aged 65 and abovewere more likely to receive medication than were older 
enrollees in other race/ethnicity groups.  
28 After two years of continuous treatment and a determination that the patient is responsible in handling opioid drugs, 
patients may receive up to one months worth of take-home doses.  42 CFR  8.12(i)(3)(vi).  
29 Buprenorphine and naltrexone can also be administered or dispensed at opioid treatment programs, but it is far more 
common for an enrollee to receive these medications in office-based settings. 
30 B. Andraka-Christou, Addressing Racial and Ethnic Disparities in the Use of Medications for Opioid Use Disorder, Health 
Affairs, June 2021, Vol. 6, No. 40.  Also see SAMHSA, The Opioid Crisis and The Black/African American Population: An Urgent 
Issue, April 2020.  Accessed at https://store.samhsa.gov/sites/default/files/SAMHSA_Digital_Download/PEP20-05-02-
001_508%20Final.pdf on June 21, 2021.  Also see SAMHSA, The Opioid Crisis and The Hispanic/Latino Population: An Urgent 
Issue, July 2020.  Accessed at https://store.samhsa.gov/sites/default/files/pep20-05-02-002.pdf on June 21, 2021. 
31 National Institute on Drug Abuse, Naloxone for Opioid Overdose: Life-Saving Science, June 2021.  Accessed at 
https://nida.nih.gov/publications/naloxone-opioid-overdose-life-saving-science on August 10, 2022. 
32 The total number of prescriptions for naloxone also increased, reaching 703,625 prescriptions in 2022a 40-percent 
increase from 2021. 
33 Additional enrollees may have received naloxone other than through Part D.  Notably, most States allow for third-party 
prescriptions, which means that family members or friends of an at-risk patient can get a prescription for naloxone in their own 
name.  In addition, a number of recent initiatives have increased community-based distribution of naloxone.  Also, enrollees 
who did not receive naloxone through Part D in 2022 may still have naloxone that they received through Part D from a prior 
year. 
34 In 2022, 14 percent of all naloxone dispensed through Part D was for brand-name Narcan and 83 percent was for generic 
equivalents of Narcani.e., 4 mg naloxone nasal spray products. 
35 The definition of a Part D drug does not include over-the-counter products.  As such, they cannot be covered by Part D 
under the basic drug benefit or as a supplemental benefit.  According to CMS, when a Part D covered drug switches to over-
the-counter status, its existing inventory labeled as prescription only will continue to satisfy the definition of a Part D drug and 
will continue to be covered by Part D until its inventory runs out.  See CMS, Medicare Prescription Drug Benefit Manual, Ch. 6, 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250   Endnotes | 34   
Sec. 10.10 - Over-the-Counter Products (OTCs), January 15, 2016.  Accessed at https://www.cms.gov/medicare/prescription-
drug-coverage/prescriptiondrugcovcontra/downloads/part-d-benefits-manual-chapter-6.pdf on August 1, 2023. 
36 There are some exceptions in which Medicare may provide over-the-counter drugs under a plan utilization management 
program or step therapy protocol, but the costs are treated as administrative costs and not Part D drug costs.  For more 
information, see CMS, Medicare Prescription Drug Benefit Manual, Ch. 6 - Part D Drugs and Formulary Requirements, Sec. 
10.10 - Over-the-Counter Products (OTCs), January 15, 2016.  Accessed at https://www.cms.gov/medicare/prescription-drug-
coverage/prescriptiondrugcovcontra/downloads/part-d-benefits-manual-chapter-6.pdf on August 1, 2023.  Also see CMS, 
Medicare Prescription Drug Benefit Manual, Ch. 7, Sec. 60.2  Over-the-Counter Drugs as Part of Utilization Management 
Programs, February 19, 2010.  Accessed at https://www.cms.gov/medicare/prescription-drug-
coverage/prescriptiondrugcovcontra/downloads/dwnlds/chapter7pdf on October 3, 2023. 
37 See FDA, FDA Approves First Over-the-Counter Naloxone Nasal Spray, March 29, 2023.  Accessed at 
https://www.fda.gov/news-events/press-announcements/fda-approves-first-over-counter-naloxone-nasal-spray on June 2, 
2023.   
38 According to FDA, there will be a transition period when the switch of Narcan and its generic equivalents to over-the-
counter status is being implemented.  During this period, FDA will work with manufacturers seeking to switch their generic 
equivalent prescription naloxone products to nonprescription (i.e., over-the-counter) status.  See FDA, FDA takes steps to 
decrease barriers for overdose reversal agents with Dr. Marta Sokolowska Q&A With FDA Podcast Transcript, July 10, 2023.  
Accessed at https://www.fda.gov/drugs/news-events-human-drugs/fda-takes-steps-decrease-barriers-overdose-reversal-
agents-dr-marta-sokolowska on September 25, 2023. 
39 Emergent, Emergent BioSolutions NARCAN Nasal Spray Launches Over the Counter Making it Possible for Everyone to Help 
Save a Life from an Opioid Overdose Emergency, August 30, 2023.  Accessed at 
https://investors.emergentbiosolutions.com/node/22286/pdf on September 1, 2023.  Note that the cost-sharing amounts and 
price of Narcan are based on two doses.   
40 CMS, Memo to All Medicare Advantage Organizations; Prescription Drug Plan Sponsors; Medicare-Medicaid Plans on 
Supplemental Benefit Coverage of Over-the-Counter Naloxone, April 11, 2023.  In addition, Part B will continue to cover 
naloxone that is provided by opioid treatment programs along with other treatment services.   
41 42 U.S.C.  1396r-8(k)(4). 
42 In May 2023, FDA approved Opvee, a nalmefene hydrochloride nasal spray.  In addition, Medicare Part B will continue to 
cover naloxone provided by opioid treatment programs.  For more information about Opvee, see FDA, FDA Approves 
Prescription Nasal Spray to Reverse Opioid Overdose, May 22, 2023.  Accessed at https://www.fda.gov/news-events/press-
announcements/fda-approves-prescription-nasal-spray-reverse-opioid-overdose on June 23, 2023.    
43 In addition to the risk of dependence and overdose, opioids carry other health risks, including respiratory depression, 
constipation, drowsiness, and confusion.  Older adults may also be at an increased risk of injury, as research has shown that the 
risk of fracture may increase as drug dosage increases.  See D.L. Chau, V. Walker, L. Pai, et al., Opiates and Elderly: Use and 
Side Effects, Clinical Interventions in Aging, Vol. 3, No. 2, June 6, 2008, p. 276.  D. Dowell, K.R. Ragan, C.M. Jones, G.T. Baldwin, 
R. Chou, CDC Clinical Practice Guideline for Prescribing Opioids for Pain  United States, 2022, MMWR Recomm Rep 
2022;71(No. RR-3):195.  Accessed at https://www.cdc.gov/mmwr/volumes/71/rr/pdfs/rr7103a1-H.pdf on June 6, 2023.  K.W. 
Saunders, K.M. Dunn, J.O. Merrill, et al., Relationship of Opioid Use and Dosage Levels to Fractures in Older Chronic Pain 
Patients, Journal of General Internal Medicine, Vol. 25, No. 4, January 19, 2010, pp. 310315. 
44 Between 2016 and 2020, the number of enrollees OIG identified as at serious risk of opioid misuse or overdose decreased 
between 14 percent and 32 percent annually. 
45 States maintain databasescalled prescription drug monitoring programsthat track prescriptions for controlled 
substances.  Prescribers can check these databases before ordering opioids to determine whether an enrollee is already 
receiving opioids ordered by other prescribers.  State requirements for checking this information vary.  For more information 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250   Endnotes | 35   
about prescription drug monitoring programs, see the website of the Prescription Drug Monitoring Program Training and 
Technical Assistance Center at http://www.pdmpassist.org/. 
46 Specifically, 56 prescribers each ordered opioids for at least 26 enrollees who received extreme amounts of opioids in 2022.  
Further, 53 prescribers each ordered opioids for at least 5 enrollees who appeared to be doctor shopping.  Eight prescribers 
ordered opioids for high numbers of enrollees in both groups at serious risk. 
47 Of the 101 prescribers in 2022, 63 were also identified in at least one previous year (2016 through 2021) as having 
questionable prescribing. 
48 The Drug Addiction Treatment Act of 2000 (Title XXXV of the Childrens Health Act of 2000, P.L. No. 106-310) allowed 
providers to obtain a waiver to prescribe Schedule III, IV, and V drugsincluding buprenorphinefor substance use disorder 
treatment in office settings.  Section 1262 of the Consolidated Appropriations Act, 2023 (P.L. No. 117-328), removed the waiver 
requirement. 
49 CMS, CMS Behavioral Health Strategy, May 2022.  Accessed at https://www.cms.gov/cms-behavioral-health-strategy on July 
31, 2023. 
50 OIG, The Risk of Misuse and Diversion of Buprenorphine for Opioid Use Disorder Appears to Be Low in Medicare Part D (OEI-02-
22-00160) April 16, 2023.   
51 OIG, Many Medicare Beneficiaries Are Not Receiving Medication to Treat Their Opioid Use Disorder (OEI-02-20-00390) 
December 15, 2021. 
52 OIG, Many Medicaid Enrollees with Opioid Use Disorder Were Treated with Medication; However, Disparities Present Concerns 
(OEI-BL-22-00260) September 26, 2023. 
53 According to CMS, when a Part D covered drug switches to over-the-counter status, any existing inventory of the drug 
labeled as prescription only will continue to satisfy the definition of a Part D drug and will continue to be covered by Part D 
until the inventory runs out.  In addition, according to FDA, there will be a transition period during implementation of the 
switch of Narcan and its generic equivalents to over-the-counter status.  During this period, the remaining stocks of 
prescription Narcan will remain available.  FDA will also work with manufacturers seeking to switch their generic equivalent 
prescription naloxone products to nonprescription (i.e., over-the-counter) status.  See CMS, Medicare Prescription Drug Benefit 
Manual, Ch. 6, Sec. 10.10 - Over-the-Counter Products (OTCs), January 15, 2016.  Accessed at 
https://www.cms.gov/medicare/prescription-drug-coverage/prescriptiondrugcovcontra/downloads/part-d-benefits-manual-
chapter-6.pdf on August 1, 2023.  Also see FDA, FDA takes steps to decrease barriers for overdose reversal agents with Dr. Marta 
Sokolowska Q&A With FDA Podcast Transcript, July 10, 2023.  Accessed at https://www.fda.gov/drugs/news-events-human-
drugs/fda-takes-steps-decrease-barriers-overdose-reversal-agents-dr-marta-sokolowska on September 25, 2023. 
54 MED and MME are interchangeable terms. 
55 For more information on calculating opioid dosage, see CDC, Calculating Total Daily Dose of Opioids for Safer Dosage.  
Accessed at https://www.cdc.gov/drugoverdose/pdf/calculating_total_daily_dose-a.pdf on September 1, 2023. 
56 We included opioids dispensed in 2021 with days of use in 2022.  This analysis excludes prescriptions for injection, 
intravenous, and intrathecal opioids, as well as opioids indicated for opioid use disorder. 
57 We identified enrollees with a cancer diagnosis or hospice stay by using CMSs National Claims History File and Part C 
Encounter data.  In total, we identified 2,983,321 enrollees with cancer or in hospice care who received at least 1 opioid. 
58 We selected these criteria because they closely align with the criteria that CMS used in 2016 and 2017 for its Overutilization 
Monitoring System.  Through 2017, CMSs Overutilization Monitoring System identified enrollees who had a daily MED of 120 
mg for 90 days plus four or more prescribers and four or more pharmacies.  Note that the guidance uses the term more than 
3 prescribers and more than 3 pharmacies, which is the equivalent of 4 or more prescribers and 4 or more pharmacies.  The 
criteria for the Overutilization Monitoring System changed in 2018.  See CMS, Announcement of Calendar Year (CY) 2018 
Medicare Advantage Capitation Rates and Medicare Advantage and Part D Payment Policies and Final Call Letter and Request for 
 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250   Endnotes | 36   
Information, April 3, 2017.  Accessed at https://www.cms.gov/Medicare/Health-
Plans/MedicareAdvtgSpecRateStats/Downloads/Announcement2018.pdf on September 1, 2023. 
59 For our analysis, we counted prescribers in group practices separately. 
Data Brief: The Consistently Low Percentage of Medicare Enrollees Receiving Medication to Treat Their Opioid Use Disorder 
Remains a Concern, OEI-02-23-00250   Endnotes | 37