Medicare Formulary Coverage and Restrictions for Opioid Potentiators from 2013 to 2017

INTRODUCTION

In 2015, 38% of adults used prescription opioids, with slightly higher rates among older adults.¹ Risks of opioids have been well-described and are greater among older adults and when used concurrently with three commonly prescribed “opioid potentiator” drug classes: benzodiazepines, non-benzodiazepine sedative hypnotics, and gabapentinoids.^{2, 3} These drugs also have risks when used on their own; in particular, there has been an increasing risk of death associated with benzodiazepine use.⁴

Medicare formulary coverage and utilization management strategies, including quantity limits, prior authorization, and step therapy, offer opportunities to limit potentially unsafe use of opioid potentiators, similar to coverage restrictions of opioids.⁵ Based on Centers for Disease Control guidelines that propose more limited opioid availability and the fact that formulary restrictions are infrequently used to control opioid prescribing, Medicare recently proposed formulary changes to restrict opioid availability based on maximum daily dosage and initial fill quantity.⁶ Many states have also legislated quantity limits for opioids.

However, coverage of opioid potentiator medications is unknown. Medicare began covering benzodiazepines in 2013 for select conditions, broadening coverage in 2014 for any medically accepted indication. We characterized Medicare formulary coverage of benzodiazepines, non-benzodiazepine sedative-hypnotics, and gabapentinoids from 2013 to 2017.

METHODS

We used 2013, 2015, and 2017 Medicare Prescription Drug Formulary Files, which include data on all Medicare Advantage and Stand-alone Part D plan formularies. We identified all benzodiazepines, non-benzodiazepine sedative-hypnotics, and gabapentinoids available in oral formulations. We characterized median formulary coverage of the lowest dose of the generic version of each drug, or the brand-name version when generics were unavailable. We focused on generics since they are used more commonly than the bioequivalent brand-name version, and on the lowest dose because higher doses can be created from lower doses. We excluded two brand-name drugs (Rozerem and Lunesta) that became available as a generic between 2013 and 2017, as generic availability impacts brand-name formulary coverage.

For each drug in each year, we determined the proportion of formularies not providing coverage; providing restrictive coverage using one or more utilization management strategy (quantity limit, prior authorization, or step therapy); or providing unrestrictive coverage (no utilization management). We summarized median coverage across all drugs in all three years. Analyses were conducted in R Studio version 3.2.3.

RESULTS

There were 12 benzodiazepines, 3 non-benzodiazepine sedative hypnotics, and 3 gabapentinoids eligible for the study. The median proportion of formularies not providing coverage across all drugs was 21.8% (interquartile range [IQR], 0.3–64.8%) in 2013, 14.4% (IQR, 0.0–66.3%) in 2015, and 17.6% (IQR, 0.0–68.7%) in 2017 (Table 1). The median proportion of formularies providing restrictive coverage was 63.3% (IQR, 49.6–69.4%) in 2013, 70.1% (IQR, 65.8–81.2%) in 2015, and 66.8% (IQR, 54.4–77.9%) in 2017, with the largest growth in use of quantity limits, a smaller increase in prior authorization, and infrequent use of step therapy. The median proportion of formularies providing unrestrictive coverage in the 3 years was 33.3% (IQR, 27.1–43.7%), 27.0% (IQR, 16.3–32.2%), and 27.9% (IQR, 18.0–41.6%), respectively. In 2017, 47.9% of formularies provided unrestrictive coverage of at least 1 benzodiazepine, 39.9% of at least 1 non-benzodiazepine sedative-hypnotic, and 67.2% of at least 1 gabapentinoid.

Table 1.

Median Medicare Prescription Drug Plan Formulary Coverage and Use of Utilization Management Strategies for Benzodiazepines, Non-benzodiazepine Sedative Hypnotics, and Gabapentinoids, 2013–2017

	Median formulary coverage (interquartile range), %
	2013 formularies (n = 314)	2015 formularies (n = 389)	2017 formularies (n = 378)
No coverage	21.8 (0.3–64.8)	14.4 (0.0–66.3)	17.6 (0.0–68.7)
Restrictive coverage	63.3 (49.6–69.4)	70.1 (65.8–81.2)	66.8 (54.4–77.9)
Imposes a quantity limit	44.8 (34.6–54.8)	58.7 (39.1–68.4)	59.8 (41.5–70.0)
Requires prior authorization	16.4 (11.8–23.5)	31.9 (17.2–38.8)	21.0 (14.0–39.0)
Requires step therapy	0 (0–0)	0.0 (0.0–2.7)	0 (0–0.8)
Coverage with no restrictions	33.3 (27.1–43.7)	27.0 (16.3–32.2)	27.9 (18.0–41.6)

12 benzodiazepines, 3 non-benzodiazepine sedative-hypnotics, and 3 gabapentinoids were included

Medicare coverage in 2017 of each drug varied (Table 2). Quazepam and gabapentin enacarbil were not covered by any plan, whereas lorazepam, diazepam, clonazepam, doxepin, pregabalin, and gabapentin were covered by all. Among benzodiazepines, hypnotics (estazolam, flurazepam, and triazolam) had lower rates of coverage, whereas anxiolytics (alprazolam, diazepam, and lorazepam) had higher rates, albeit usually with restrictions.

Table 2.

Medicare Prescription Drug Plan Formulary Coverage and Use of Utilization Management for Individual Benzodiazepines, Non-benzodiazepine Sedative Hypnotics, and Gabapentinoids, 2017 Second Quarter

Formulary coveragea	No coverage (%)	Unrestrictive coverage (%)	Restrictive coveragea (%)	Imposes a quantity limit (%)	Requires prior authorization (%)	Requires step therapy (%)
Benzodiazepines
Alprazolam	11.9	21.9	67.1	75.7	7.5	0
Chlordiazepoxide	48.9	37.6	13.5	57.4	17.7	0
Clonazepam	0	28.8	71.2	62.2	22.5	2.1
Clorazepate	0	27.2	72.8	63.8	37.0	0
Diazepam	0	19.6	80.4	72.0	39.7	0
Estazolam	59.4	33.6	7.0	55.9	23.4	0
Flurazepam	56.9	38.2	4.9	45.2	17.9	0
Lorazepam	0	17.5	82.5	74.6	19.6	0
Oxazepam	33.9	28.6	37.5	34.6	28.3	0
Quazepamb	100
Temazepam	45.2	22.8	32.0	63.8	58.5	0
Triazolam	60.3	36.5	3.2	53.3	13.3	0
Non-benzodiazepine sedative hypnotics
Doxepin	0	39.4	60.6	0	57.1	3.4
Zaleplon	23.3	3.8	72.9	78.6	54.8	10.0
Zolpidem	4.5	1.4	94.1	84.5	65.4	8.3
Gabapentinoids
Gabapentin	0	59.8	40.2	40.2	0	0
Gabapentin enacarbilb	100
Pregabalin	0	28.6	71.8	64.0	16.1	1.1

^aRestrictive coverage defined as use of one or more utilization management strategy: quantity limit, prior authorization requirement, and step therapy requirement

^bDrug was not covered by any formulary over the study period

DISCUSSION

From 2013 to 2017, Medicare prescription drug plan formularies had relatively unchanged rates of benzodiazepine, non-benzodiazepine sedative hypnotic, and gabapentinoid coverage with small increases in the use of quantity limits. More than a quarter of formularies provided unrestrictive coverage of these potentially unsafe opioid potentiators in 2017, and approximately 20% provided unrestrictive coverage of alprazolam and lorazepam, the two most commonly prescribed benzodiazepines. Furthermore, despite concern about the potential for prescription abuse, gabapentin was covered without restrictions by almost 60% of formularies.

The CMS overutilization monitoring system currently flags co-prescription of benzodiazepines and opioids, and CMS has proposed flagging co-prescription of other potentiator drugs with opioids.⁶ Although we could not examine co-restriction of opioids and opioid potentiators using Medicare formulary data, our findings suggest opportunity for greater use of utilization management strategies to reduce use of these potentially unsafe medications.

Compliance with Ethical Standards

Conflict of Interest

Over the past 36 months, Dr. Ross received support through Yale University from the Food and Drug Administration as part of the Centers for Excellence in Regulatory Science and Innovation (CERSI) program, from Johnson and Johnson to develop methods of clinical trial data sharing, from Medtronic, Inc. and the Food and Drug Administration (FDA) to develop methods for postmarket surveillance of medical devices, from the Blue Cross Blue Shield Association to better understand medical technology evaluation, from the Centers for Medicare and Medicaid Services (CMS) to develop and maintain performance measures that are used for public reporting, from the Agency for Healthcare Research and Quality (AHRQ) to examine community predictors of healthcare quality, and from the Laura and John Arnold Foundation, which established the Collaboration for Research Integrity and Transparency (CRIT) at Yale University. Dr. Shah received support from the Food and Drug Administration as part of the Centers for Excellence in Regulatory Science and Innovation (CERSI) program, through the Mayo Clinic from the Centers for Medicare and Medicaid Services (CMS), Agency for Healthcare Research and Quality (AHRQ), National Science Foundation, and Patient-centered Outcomes Research Institute (PCORI). All remaining authors declare that they do not have a conflict of interest.

Disclaimer

The authors assume full responsibility for the accuracy and completeness of the ideas presented, which do not represent the views of the Department of Veterans Affairs or any other supporting institutions