Health Care Costs and Financing

Combination antihypertensive drugs raise out-of-pocket costs for patients

Patients with high blood pressure who use frequently prescribed combination antihypertensive medications pay an average of $13.38 more per month for their medication, compared with the cost of their medication's generic components, according to a new study.

Most patients with hypertension require more than one medication and over 14 percent of all antihypertensive prescriptions are for fixed-dose combination drugs. These drugs, which combine two or more drugs from different therapeutic classes into a single tablet, simplify prescription regimens and may thus increase the likelihood that patients will take their medicines as prescribed. However, many medicines marketed as fixed-dose combinations are available as brand-name drugs alone and are typically considerably more expensive than their generic equivalents. Also, physicians are much more likely to prescribe brand name medicine if they use a combination antihypertensive than a noncombination therapy, explain researchers Atonu Rabbani, Ph.D., and G. Caleb Alexander, M.D. They studied 27 commonly prescribed combination antihypertensives and found that for 24 of them, there was an average 41 percent increase in out-of-pocket costs. The differences in costs varied considerably, ranging from a decreased cost of $1.10 to an increased cost of $60.41.

Using data from the Medical Expenditure Panel Survey, the researchers compared out-of-pocket and third-party costs for a 30-day supply of 27 brand name fixed-dose combination antihypertensives with the sum of the costs for their individual generic components. In contrast to the higher out-of-pocket costs, the researchers found that total third-party costs were lower with fixed-dose combination medicines for 23 of the 27 drugs examined. The mean decrease in monthly prescription costs was $20.89 with a combination medicine, reflecting a 32 percent reduction in total monthly prescription costs.

In a secondary analysis including both brand name and generic combination antihypertensives, the researchers found a much smaller increase in average out-of-pocket costs (only 2 percent greater, as opposed to 41 percent) for the generic combination medications. Similarly, the total costs for the combination antihypertensives were 14 percent less (compared with 32 percent) than their constituent drugs.

The authors stress the importance of their findings because many patients experience burdensome out-of-pocket costs, antihypertensives are some of the most commonly prescribed prescription drugs, and modest reductions in out-of-pocket costs may be quite meaningful for many poor and elderly patients. This study was supported by the Agency for Healthcare Research and Quality (HS15699).

See "Out-of-pocket and total costs of fixed-dose combination antihypertensives and their components," by Drs. Rabbani and Alexander, in the May 2008 American Journal of Hypertension 21(5), pp. 509-513.

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