Why aren't drugs safe when they are approved?

Q. First it was Vioxx and now Avandia. Why can’t doctors and the government screen out unsafe medicines?

A. The FDA requires testing for effectiveness and safety before it approves a drug. As citizens, we want the agency to thoroughly examine the safety of a drug before approving it, but we also want the FDA to move as quickly as possible to approve new medicines. You see the dilemma.

When a drug has a serious but rare side effect, very large studies may be needed to uncover it. Even then, sometimes side effects are discovered only after the drug is on the market, and many people have taken it. There’s a great deal of interest in beefing up systems for post-approval surveillance of drugs so doctors and patients know about dangerous side effects as soon as possible.

Avandia (rosiglitazone) lowers the blood sugar of people with type 2 diabetes. A meta-analysis, which combines the results of smaller studies, found Avandia increases the risk for heart attack. A couple of weeks later, the drug’s manufacturer, GlaxoSmithKline, reported interim results from a large randomized trial that’s scheduled to last another three years. Those results showed a clear increase in certain types of heart problems, particularly heart failure, but were inconclusive for some others, such as heart attacks.

The FDA had asked Glaxo to add a “black box” warning about the heart failure risk, but has allowed the drug to remain on the market.

Ultimately, Avandia’s fate will be determined by the results from Glaxo’s randomized trial. If it shows no increase in heart disease risk, most people will believe that the company and FDA did the right thing keeping the drug on the market.

— Anthony L. Komaroff, M.D.
Harvard Health Letter Editor in Chief

What is your reaction to the news of Avandia being linked to heart problems?

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