Ketek is an antibiotic with a deserved reputation as an effective treatment for bacterial respiratory infections. But erythromycin and all its derivatives, including Ketek, have some degree of liver toxicity. Erythromycin, the granddaddy of the class, has been known for years to cause severe, but rare, cases of liver failure. Yet its overall reputation remains unblemished.

Ketek is now being deemed as unusually toxic—at least according to a recent safety review by FDA officials. These officials have suggested that the FDA either force Sanofi-Aventis to withdraw Ketek from the market, severely restrict it, or at least add a stern warning to its label.
Meanwhile, more than 5 million Ketek prescriptions have been written since its approval two years ago. Out of this number, 12 have sustained liver failure, four of these have died, while 23 others have suffered damaged livers.

What should be done? The key here is to understand the concept of risk-benefit ratio, where the risk of a drug is compared with how rare the complication is and how life saving the drug is. Unfortunately, when the media targets a drug, as it has with Ketek, the ability to make a sober cost-benefit analysis is quickly lost. As the drug stock and the number of written prescriptions plummet, the realization that these are rare side effects is quickly lost. Yet, in the vast majority of cases the drug remains safe.

 Even I, writer of this “rational” column, find myself remembering that I have both prescribed and taken Ketek liberally over the past several months, and in a brief moment of irrational overpersonalization of a remote risk, I wonder if my own liver is okay.

But whatever the outcome for Ketek, the decision should be based on facts and statistical risks compared with the potential gain of lives saved. Media-induced hysteria results in a perceived danger well beyond the actual danger, and should be removed from the drug safety equation as much as possible.

Marc Siegel, MD, is an internist and associate professor of medicine at New York University and the author of False Alarm: The Truth About the Epidemic of Fear.