Utilization, spending, and price trends for benzodiazepines in the US Medicaid program: 1991-2009

Although it is well-known that drug costs in the US have risen precipitously over the last 25 years, what is much less appreciated is how this rise in cost has occurred across so many seemingly distinct drug markets.

To describe trends in the utilization, spending, and average per-prescription cost of benzodiazepines individually, in subgroups, and overall, in the Medicaid program. Medicaid has been the primary public payer for benzodiazepines over the past 2 decades.

A retrospective, descriptive analysis was performed for the years 1991-2009 using the publicly available national Summary Files from the Medicaid State Drug Utilization Data maintained by the Centers for Medicare & Medicaid Services. Quarterly prescription counts and reimbursement amounts were calculated for all benzodiazepines reimbursed by Medicaid. Average per-prescription spending as a proxy for drug price was found by dividing reimbursement by the number of prescriptions.

Prescriptions for benzodiazepines among Medicaid beneficiaries increased from 8.0 million in 1991 to 17.1 million in 2009. Expenditures rose from $131.6 million to $171.1 million over the same time period. The average per-prescription price was a little over $10 in 2009. Whereas utilization of intermediate- and long-acting agents increased over time, prescriptions for short-acting drugs fell from 1.1 million to 0.3 million (1991-2009). The percentage rise in Medicaid spending on benzodiazepines since 1991 (30.0%) was less than the general rate of inflation (57.5%), as measured by the percentage change in the consumer price index over the same time period.

Relative to the rise in the number of Medicaid beneficiaries (more than doubled over the study period), there is no evidence of an extraordinary rise in the utilization of benzodiazepines. Moreover, both nominal and real average prices of benzodiazepines have fallen, primarily because of generic entry over the last 2 decades.