To fear or not to fear -- the truth about Zithromax

The FDA decided to warn the American public this month that the ultra-popular antibiotic azithromycin (brand name Zithromax), may have the potential for provoking a fatal heart rhythm.

This news is not new and the remote risk is primarily found in patients with a previous heart rhythm problem, low levels of potassium or magnesium,or a low heart rate.

Unfortunately, lost in the media blitz that followed is factual information about just how safe the drug actually is.


Over 40 million patients are prescribed Zithromax every year for everything from a sore throat to bronchitis to gonorrhea. But millions who were quick to grab for the handy-dandy 5 day Z-pack for every sniffle yesterday are likely to run from it fearfully today, over-personalizing the remote risk.

At first this may seem like a helpful reaction. Zithromax is known for its overuse and cost ($464 million per year according to IMS Health). But fear isn’t the best teacher.

All antibiotics have some side effects, so whatever drug patients reach for instead of the Z-pack is not entirely without risk either. And those who are now afraid to take it may be among the group who actually need it.

Ironic, isn’t it, that an overblown fear of a drug, Zithromax, is now replacing the overblown fear of bronchitis and sinus infections (mostly viral and not responsive to antibiotics), that has led doctors to overprescribe the drug and patients to clamor for it.

Several years ago I met the Pfizer chemist who was responsible for the success of Zithromax. He was about to discard it as ineffective when he discovered that the drug hid in the body’s tissues, meaning that even after you thought it was out of your system it still had a therapeutic effect.

This led to the extremely popular notion behind the Z-pack, where you only have to take the drug for five days yet it continues to fight infection for several days beyond that. The pure convenience of the Z-pack has led doctors to prescribe it to billions of patients.

Then last year a study in the New England Journal of Medicine revealed that approximately one in four thousand patients at high risk for having a heart arrhythmia died after taking Zithromax. The risk is extremely low, especially in people without heart problems, (47 additional deaths per million courses of the drug).

Not only that, but the study doesn’t prove that Zithromax is the reason for the deaths. Zithromax is in the same family of drugs as erythromycin, a very safe antibiotic that doctors have been prescribing for decades, that has also been associated with the very same problem – but only extremely rarely.

So this month’s news is not new, it only feels new, because of the sense of immediacy and concern that the media coverage brings.

The same problem occurred last year, when the FDA added a warning to the Lipitor label that indicated it might be associated with thinking problems or diabetes. The studies that led to this warning did not prove that Lipitor caused these problems.

But all of a sudden, my patients and patients everywhere were afraid to take the drug. Keepin mind that cholesterol-lowering statins have been proven to decrease heart attack and stroke risks and save countless lives, so it is important for doctors to be able to put the potential risk of muscle aches or diabetes or the more remote risk of cognitive difficulties in context for their patients. Yet after the FDA warning tore through the media, many patients became afraid to take the statin drugs.

Fear is our brain’s warning system against imminent danger. Fear is not the best teacher for informing a cost/benefit analysis about a useful or a lifesaving medication. The FDA should keep this truth in mind when it makes statements or issues warnings.