Antibiotic increases sudden-death risk

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Antibiotic increases sudden-death risk

Study finds heart hazard can rise 5-fold when drugs react with

erythromycin

By Bor and Kohn

Sun Staff

Originally published September 9, 2004

A commonly used antibiotic increases the risk of sudden cardiac

death, particularly when taken with certain blood pressure

medications and other drugs, doctors said yesterday.

The antibiotic, erythromycin, is used to treat a wide range of

bacterial infections, from bronchitis to pneumonia. The increased

risk has been known for years, but this is the first study to

establish the extent of the hazard.

" We tried to put a quantity on the risk, " said one of the authors,

Stein, a clinical pharmacologist at the Vanderbilt University

School of Medicine in Nashville. Stein and other researchers at the

school combed through Medicaid records of Tennessee residents and

found that people taking the drug had double the risk of sudden

death.

But the risk was fivefold among people taking erythromycin and

various other drugs that seemed to increase the antibiotic's

concentration in the bloodstream.

Though small, the risk was sufficient for the Vanderbilt researchers

to advise doctors not to prescribe the drugs in combination,

particularly because there are good alternatives.

Among the drugs with which erythromycin reacts are the blood pressure

medications verapamil and diltiazem and the anti-fungal medications

fluconazole, ketoconazole and itraconazole.

The study appears in today's New England Journal of Medicine.

Stein emphasized that even for those in the high-risk group, " the

level of risk is low. "

" In the average person who's healthy, it's generally a safe drug, " he

said. In 1997, the blockbuster antihistamine Seldane was taken off

the market in the wake of reports of sudden death among people taking

it in combination with erythromycin. The allergy drug seemed to raise

blood levels of the antibiotic.

In both those cases and the

ones cited yesterday, the drug combinations were associated with an

abnormal rhythm in the left ventricle, the heart's main pumping

chamber, which can trigger sudden death in otherwise healthy people.

The risk appears to be greater among women, the researchers said.

It is difficult to pinpoint exactly how many Americans use

erythromycin, Stein said. The drug has long been a generic and is

produced by several companies.

" It's one of the most commonly used antibiotics, " Stein said.

Dr. Muhamed Saric, a cardiologist at the University of Medicine and

Dentistry of New Jersey, said heart specialists were aware of the

drug's potential risks for years, but he suspects that some general

practitioners were not.

" In most cases, there is not a compelling reason to use erythromycin

over other antibiotics, " said Saric, calling the risk unacceptably

high. " There is such a panoply of antibiotics. "

Stein said the researchers would likely turn their attention to other

classes of antibiotics, to see whether these drugs also raise the

risk of cardiac arrest. Case reports suggest this might be true for

some of these drugs, he said, though the Vanderbilt study found no

heightened risk with amoxicillin, another common antibiotic.

Dr. Gottlieb, head of the cardiac care unit at the University

of land School of Medicine, said doctors have long known that

erythromycin when used with certain other drugs can trigger an

abnormally fast heart rhythm called torsade de pointes that can be

fatal.

" But there are risk factors from any medicine, " Gottlieb said,

pointing out that some cause severe allergic reactions. " Bad things

can happen, and they always have to be considered. "

Copyright © 2004, The Baltimore Sun