ARB costs run high in Medicare Part D

Researchers at Brigham and Women’s Hospital, in a cross-sectional analysis of 1,446 Medicare Part D formularies to determine the presence and utilization of angiotensin receptor blockers (ARBs), found that people who have been in a Medicare supplement plan will pay more for these drugs when they join a Part D plan.

Also, any savings from lower copayments under Part D may be offset by the monthly premium and by more expensive cost-sharing when beneficiaries reach the “doughnut hole.”

Depending on how broadly a formulary defines the class of renin-angiotensin-aldosterone system inhibitors, of which ARBs and angiotensin-converting enzyme (ACE) inhibitors are a part, formularies could contain two ACE inhibitors and no ARBs. This could be detrimental to patients who cannot tolerate ACE inhibitors.

“The ARBs valsartan and losartan are the most commonly found ARBs on formularies, which will limit therapeutic substitution,” says Walid F. Gellad, MD, lead author of the study. “Nonetheless, there will be some patients who will have to switch ARBs when they join Part D,” says Gellad.

Under Part D, the average prescription cost-sharing for each of the ARBs ranges from $28 to $47. Average copayments were more than twice as high for the Part D plans, compared to commercial copayments. About one-half of patients who take ARBs will be affected by the doughnut hole and there will be no generic ARBs until at least 2009, when the patent on losartan (Cozaar) expires.

Paying more under Part D

People who paid the whole cost of their ARB prescriptions before Part D may pay less on average if they join a Medicare Part D prescription drug plan, but those who had supplemental coverage and paid between $11.76 and $15.58 for a 30-day supply would pay substantially more under Part D.

Source: Gellad, WF, et al. Angiotensin receptor blockers on the formularies of Medicare drug plans. J Gen Intern Med. 2007 Aug;22(8):1172-5