U.S. Department of Health and Human Services
Office of Inspector General
Data Snapshot
June 2022, OEI-05-22-00230
Part D Plans Generally Include Drugs Commonly Used by Dual 
Eligibles: 2022
Key Takeaway
Why OIG Did This Review
Dual eligiblesthat is, beneficiaries who are covered by both Medicare and  Dual eligibles have access 
Medicaidare a vulnerable population whose access to prescription drugs is  to the majority of 
particularly important. Overall, they have very low incomes andbecause they are  commonly used drugs in 
more likely to be in poorer health than other Medicare beneficiariestend to use  2022 via Part D plans. 
more Medicare services.1Because Medicare prescription drug coverage is an  This is consistent with 
important tool for ensuring access to prescription drugs, Congress mandated that  OIGs findings from 
OIG study whether Part D formularies cover prescription drugs commonly used by  previous years. Dual 
dual eligibles.2 eligibles have several 
options if their plans do 
not cover specific drugs; 
What OIG Did
however, these options 
For this report, we determined whether the 449 unique formularies used by the  may be burdensome and 
5,288 Part D plans operating in 2022 cover 195 of the 200 drugs most commonly  do not guarantee access 
used by dual eligibles. See the methodology for more information about how we  to the drugs. 
determined the most commonly used drugs. This is OIGs twelfth annually mandated 
report examining dual eligibles access to drugs under Medicare Part D. 
Results
A majority of the 449 Part D plan formularies  Part D plans with premiums below the 
covered almost all (at least 97 percent) of the  regional benchmark also covered almost all 
drugs most commonly used by dual eligibles. commonly used drugs.
Regardless of the plan in which they are enrolled, dual  Similarly, among Part D plans with premiums below 
eligibles can expect to have access to most drugs. the regional benchmark, a majority of formularies 
(95 of 132) covered at least 97 percent of the drugs 
commonly used by dual eligibles. 
Each year, the Centers for Medicare & Medicaid 
services (CMS) establishes a premium benchmark 
for Part D plans that varies by region.3 It is 
particularly important that plans with premiums 
below the regional benchmark have high 
inclusion ratesfor the most commonly used drugs 
because: 
 Dual eligibles do not need to pay additional 
amounts in premiums for these plans.4
 When CMS randomly assigns dual eligibles to 
Part D plans, it assigns them to plans with 
premiums below the regional benchmark 
without considering their specific prescription 
drug needs.5
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2022 1 Results (contd)
A small number of drugs were covered by fewer  While beneficiaries have several options if their 
than 75 percent of formularies. formularies do not cover specific drugs, these 
options require dual eligibles to take administrative 
Although formularies frequently omitted eight  actions and do not guarantee that they can get the 
commonly used drugs in 2022, they all covered  drugs.
alternative drugs in the same respective therapeutic 
Dual eligibleshaveuptothreechances 
classes, as CMS requires.6
duringthefirst9monthsoftheyearto 
switch to plans that cover the 
prescription drugs they require.7
Dual eligibles can use an exceptions 
and appeals process to request 
coverageofnonformulary drugsbytheir 
plans.8
Dual eligibles can work with their 
prescribers to find an alternative drug 
covered by their plans.
Dual eligibles can pay out of pocket for 
the noncovered drugs. 
Conclusion
When establishing formularies, Part D plans are permitted to balance Medicare beneficiaries needs for 
adequate prescription drug coverage against the need to contain costs for plan sponsors and for the Part D 
program. Part D plans may omit certain drugs from prescription coverage in order to control costs. However, 
omitting drugs from coverage can also limit the ability of beneficiaries to access the prescription drugs they 
need.
In general, dual eligibles have access to nearly all of the most commonly used drugs via their Part D plan 
formularies in 2022. A majority of these formularies covered almost all commonly used drugs, and only a small 
number of commonly used drugs were not covered by most formularies. These findings are largely unchanged 
from OIGs findings reported from 2011 through 2021. Dual eligibles have several options if their formularies 
do not cover specific drugs, but these options may be burdensome and do not guarantee access to the drugs.
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2022 2 Top 200 Commonly Used Drugs*
Generic Name Percentage  Generic Name Percentage  Generic Name Percentage 
of  of  of 
Formularies  Formularies  Formularies 
Including  Including  Including 
Drug Drug Drug
Dexlansoprazole 44% PromethazineHcl 99% RosuvastatinCalcium 100%
InsulinLispro 45% Valsartan 99% DuloxetineHcl 100%
UmeclidiniumBromide 62% Nifedipine 100% Glipizide 100%
InsulinDegludec 64% Lovastatin 100% Tramadol Hcl 100%
InsulinAspart 65% TizanidineHcl 100% DivalproexSodium 100%
InsulinDetemir 68% Fenofibrate 100% Tamsulosin Hcl 100%
TiotropiumBromide 69% Benazepril Hcl 100% InsulinGlargine,hum.Rec.Anlog 100%
SolifenacinSuccinate 75% Irbesartan 100% Prednisone 100%
Omega-3AcidEthylEsters 77% Atorvastatin Calcium 100% Mirtazapine 100%
Linagliptin 79% Amlodipine Besylate 100% EscitalopramOxalate 100%
Travoprost 82% Lisinopril 100% WarfarinSodium 100%
NebivololHcl 83% Metformin Hcl 100% Allopurinol 100%
SitagliptinPhosphate 85% Levothyroxine Sodium 100% AlendronateSodium 100%
UmeclidiniumBrm/VilanterolTr 88% Omeprazole 100% CitalopramHydrobromide 100%
Budesonide/Formoterol Fumarate 90% Gabapentin 100% BupropionHcl 100%
EsomeprazoleMagnesium 91% Furosemide 100% DiltiazemHcl 100%
Liraglutide 91% Losartan Potassium 100% FluoxetineHcl 100%
Linaclotide 92% Metoprolol Succinate 100% Risperidone 100%
Temazepam 92% Hydrocodone/Acetaminophen 100% OxycodoneHcl/Acetaminophen 100%
Alprazolam 94% Pantoprazole Sodium 100% HydralazineHcl 100%
ClobetasolPropionate 94% Nystatin 100% DiclofenacSodium 100%
Fluticasone/Vilanterol 94% Simvastatin 100% Meloxicam 100%
Dulaglutide 95% Albuterol Sulfate 100% Ibuprofen 100%
OlopatadineHcl 95% Potassium Chloride 100% Levetiracetam 100%
BrimonidineTartrate/Timolol 96% Hydrochlorothiazide 100% CyclobenzaprineHcl 100%
HydroxyzineHcl 96% Metoprolol Tartrate 100% Lisinopril/Hydrochlorothiazide 100%
Bimatoprost 96% Carvedilol 100% OxybutyninChloride 100%
Torsemide 96% Montelukast Sodium 100% Lorazepam 100%
Celecoxib 96% Trazodone Hcl 100% Losartan/Hydrochlorothiazide 100%
Tobramycin/Dexamethasone 97% Fluticasone Propionate 100% Famotidine 100%
Empagliflozin 98% Quetiapine Fumarate 100% Atenolol 100%
Apixaban 99% Sertraline Hcl 100% Pregabalin 100%
Rivaroxaban 99% Clopidogrel Bisulfate 100% IsosorbideMononitrate 100%
FenofibrateNanocrystallized 99% Pravastatin Sodium 100% Clonazepam 100%
* Of the top 200 drugs, we analyzed 195 drugs for this review. 
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2022 3 Top 200 Commonly Used Drugs (contd)*
Generic Name Percentage  Generic Name Percentage  Generic Name Percentage 
of  of  of 
Formularies  Formularies  Formularies 
Including  Including  Including 
Drug Drug Drug
ParoxetineHcl 100% HydroxychloroquineSulfate 100% Colchicine 100%
ZolpidemTartrate 100% RopiniroleHcl 100% Metronidazole 100%
Baclofen 100% MeclizineHcl 100% Hydrocortisone 100%
Spironolactone 100% Digoxin 100% Bumetanide 100%
Lamotrigine 100% LevocetirizineDihydrochloride 100% PrednisoloneAcetate 100%
DonepezilHcl 100% InsulinNphHum/RegInsulinHm 100% LabetalolHcl 100%
BuspironeHcl 100% Amoxicillin/PotassiumClav 100% Calcitriol 100%
Topiramate 100% PropranololHcl 100% Fluconazole 100%
Latanoprost 100% CiprofloxacinHcl 100% Estradiol 100%
Aripiprazole 100% MorphineSulfate 100% PrazosinHcl 100%
ClonidineHcl 100% Sulfamethoxazole/Trimethoprim 100% Gemfibrozil 100%
MemantineHcl 100% Ipratropium/AlbuterolSulfate 100% MetoclopramideHcl 100%
Glimepiride 100% Methotrexate Sodium 100% DorzolamideHcl 100%
BenztropineMesylate 100% Ketoconazole 100% VerapamilHcl 100%
Fluticasone 
100% Clozapine 100% Anastrozole 100%
Propion/Salmeterol
Olanzapine 100% AcetaminophenWithCodeine 100% Methylprednisolone 100%
Azithromycin 100% Carbidopa/Levodopa 100% Ondansetron 100%
Venlafaxine Hcl 100% Ondansetron Hcl 100% NitrofurantoinMonohyd/M-Cryst 100%
Naproxen 100% Lactulose 100% PhenytoinSodiumExtended 100%
Carbamazepine 100% Oxcarbazepine 100% Nitroglycerin 100%
AmitriptylineHcl 100% Mirabegron 100% Mupirocin 100%
EnalaprilMaleate 100% DoxycyclineHyclate 100% AmiodaroneHcl 100%
Cephalexin 100% DorzolamideHcl/TimololMaleat 100% Dextroamphetamine/Amphetamine 100%
Finasteride 100% ZiprasidoneHcl 100% IsosorbideDinitrate 100%
TriamcinoloneAcetonide 100% BrimonidineTartrate 100% AmmoniumLactate 100%
PioglitazoneHcl 100% Cyclosporine 100% ClindamycinPhosphate 100%
Chlorthalidone 100% DoxazosinMesylate 100% Ramipril 100%
OxycodoneHcl 100% Fentanyl 100% Phenobarbital** Excluded
Ezetimibe 100% Triamterene/Hydrochlorothiazid 100% Lacosamide** Excluded
PramipexoleDi-Hcl 100% Diazepam 100% RanitidineHcl*** Excluded
Amoxicillin 100% DicyclomineHcl 100% AlcoholAntisepticPads*** Excluded
Sucralfate 100% Levofloxacin 100% Ergocalciferol(VitaminD2)*** Excluded
IpratropiumBromide 100% TimololMaleate 100%
Source: OIG analysis of drugs commonly used by dual eligibles, 2022.
* Of the top 200 drugs, we analyzed 195 drugs for this review. 
**Drugs excluded from our analysis because we were unable to confidently project their use to the entire dual-eligible population.
***Drugs excluded from our analysis because they are not covered by Part D.
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2022 4 Methodology
We determined whether the unique formularies used by Part D plans operating in 2022 cover the prescription 
drugs mostly commonly used by dual eligibles.
 We used the 2019 Medicare Current Beneficiary Survey (MCBS) Cost and Use data to create a list of drugs 
with the highest utilization by dual eligibles. 
 We used the February 2022 First DataBank National Drug Data File to identify the drug product information 
for the drugs with the highest utilization by dual eligibles.
 To determine the drugs most commonly used by dual eligibles, we took the following steps:
o We created a list of all drugs reported by dual eligibles surveyed in the 2019 MCBS, 
excluding territories.
o We collapsed this list to a list of drugs based on their active ingredients.
o We ranked the drugs by frequency of utilization, weighting the drug-event information from 
MCBS by sample weight.
o We selected the 200 drugs with the highest utilization by dual eligibles.
 Of the top 200 drugs, we analyzed 195 drugs for this review. We removed three drugs not covered under 
Part D and two drugs for which we were unable to confidently project use to the entire dual-eligible 
population.
 We collected from CMS the formulary data and the plan data for Part D plans operating in 2022. The 
formulary data include Part D plans formularies for plans operating in 2022.
 We then analyzed the unique Part D plan formularies to determine their rates of inclusion of the drugs 
commonly used by dual eligibles. We counted a drug as included in a Part D plans formulary if the 
formulary included the active ingredient.
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.
Acknowledgments
Lisa Minich served as the team leader for this study, and Jonathan Carroll served as the lead analyst. Office of 
Evaluation and Inspections headquarters staff who provided support include Kaliane Davidson, Robert 
Gibbons, and Christine Moritz. This report was prepared under the direction of Laura Kordish, Regional 
Inspector General for Evaluation and Inspections in the Chicago regional office; Adam Freeman, Deputy 
Regional Inspector General; and Hilary Slover, Assistant Regional Inspector General.
Sources
1 Kaiser Family Foundation, What is the role of Medicare for dual-eligible beneficiaries?, A Primer on Medicare: Key Facts About the 
Medicare Program and the People it Covers. Accessed at https://www.kff.org/report-section/a-primer-on-medicare-what-is-the-role-of-
medicare-for-dual-eligible-beneficiaries/ onApril 6, 2022.
2For the mandate, see the Patient Protection and Affordable Care Act, P.L. No. 111-148 3313(a). For each study, OIG has reviewed 
drug coverage under Medicare Part D for all dual eligibles, rather than only for full-benefit dual eligibles as specified by themandate.  
(Under Social Security Act 1935(c)(6), full-benefit dual eligibles are individuals who are eligible for both Medicare and full Medicaid 
benefits.) With the data available for these studies, we could not confidently identify and separate full-benefit dual eligiblesand thus 
the drugs they usedfrom the total population of dual eligibles.
3 Social Security Act 1860D-14(b); 42 CFR 423.780(b)(2)(i).
4 Medicare subsidizes dual eligibles premiums, deductibles, and other cost-sharing obligations up to a determined premium benchmark 
that varies by region. Medicare Prescription Drug, Improvement, and Modernization Act of 2003, P.L. No. 108-173 (enacted Dec. 8,
2003), 101, Social Security Act 1860D-14.
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2022 5 Sources (contd) 
5 CMS randomly assigns dual eligibles to a Part D plan with premiums below the regional benchmark when (1) they become eligiblefor 
both Medicare and Medicaid but have not elected a Part D plan, (2) their current Part D plan will have a premium above the regional 
benchmark for the following year, or (3) the plan to which they were assigned is terminated. CMS, Prescription Drug Benefit Manual 
(PDBM), ch.3, 40.1.4-5.
6 Plan formularies do not generally have to include every available drug. Rather, to meet CMSs formulary requirements, they must 
include at least two drugs in each therapeutic category or class. CMS, PDBM, ch.6, 30.2.1.
783 Fed. Reg. 16440, 1651419 (Apr. 16, 2018).
8 CMS, Parts C & D Enrollee Grievances, Organization/Coverage Determinations, and Appeals Guidance, 40-60.
Part D Plans Generally Include Drugs Commonly Used by Dual Eligibles: 2022 6