Generic drugs are required to contain the same amount of active ingredient, but they aren't required to be similar in appearance to brand-name medications or to one another. In a recent study, researchers determined the number of changes in color or shape of generic cardiovascular drugs prescribed to patients who'd experienced a myocardial infarction. They also established whether the changes were associated with increased odds of episodes of nonpersistence (the time from initiation to discontinuation of therapy).

The researchers identified 11,513 patients who started treatment with a generic [beta]-blocker, angiotensin-converting enzyme inhibitor, angiotensin II receptor blocker, or statin within 90 days of discharge after a myocardial infarction. During the year after hospitalization, 3,286 (29%) had a change in pill shape or color unrelated to a change in dose.

In a nested case-control analysis, 4,573 episodes of nonpersistence (cases) were matched to 19,881 episodes of drug continuation (controls). Case patients had 34% greater odds of discordance in pill color before an episode of nonpersistence and 66% greater odds of nonpersistence after a change in pill shape.

Because changes in generic pill appearance are frequent and appear to contribute to treatment discontinuation, which can lead to significant morbidity or even death, the authors recommend that prescribers and pharmacists alert patients to the likelihood of such changes and explain that they're not clinically relevant.-KR

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