Although formularies under Medicare Part D plans vary widely, nearly all plans cover at least one brand-name drug in many commonly prescribed treatment classes, according to research published in the Journal of the American Medical Association.
The researchers, who looked at Part D plans in California, studied eight treatment classes. The classes were angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, β-blockers, calcium channel blockers, loop diuretics, selective serotonin reuptake inhibitors, statins, and thiazide diuretics.
The investigators examined how often drugs were included in at least 90% of formularies at copayments of $35 or less without prior authorization.
“Providers can have a difficult time knowing which drug is paid for by Medicare Part D because there are over 1,800 plans and there's a great deal of variation among these formularies,” Dr. Chien-Wen Tseng, a researcher at the University of Hawaii and the Pacific Health Research Institute, explained in an interview.
Nevertheless, “despite the large number of plans and variation among their formularies, for most of the treatment classes we examined we found one or more drugs that were covered by nearly 100% of Part D formularies,” Dr. Tseng added. Nearly all of these widely covered drugs are generics, according to the study, which also noted that the drugs covered by Part D formularies are likely to change over time as generics become available and as new clinical data are released (JAMA 2007;297:2596–602).
For example, simvastatin (Zocor) and sertraline (Zoloft) became available as generics in 2006.
Earlier that year, 71% of formularies had covered simvastatin as a brand name, while 74% covered sertraline as a brand name. However, by Dec. 8, 2006, after both drugs had generic equivalents, the study's authors found that 93% of the formularies examined covered simvastatin as a generic, while 100% covered sertraline as a generic.
Dr. Tseng suggested that a Web site that tracks the list of these “widely covered” drugs potentially could help physicians to determine which medications are most likely to be covered, and therefore more affordable, for their patients.
“While the large number of formularies and variation among these formularies is an inconvenience for doctors, it's a real health problem for patients because they may not get the drug they need if it's not covered or too expensive,” Dr. Tseng concluded.