One antibiotic can trigger cardiac death

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Antibiotic Can Trigger Cardiac Deaths

September 9, 2004

(The Associated Press) -- A common antibiotic prescribed for 50 years to

treat

everything from strep throat to syphilis dramatically increases the risk of

cardiac arrest, especially when taken with certain newer, popular drugs, a

study found.

The study shows the need for continuing research on the safety of older

medicines such as the widely prescribed drug, erythromycin, including how

they

interact with newer medicines, said researcher Wayne A. Ray, a professor of

preventive medicine at Vanderbilt University School of Medicine in Nashville.

In patients taking erythromycin along with other drugs that increase its

concentration in the blood, the risk of cardiac death was more than five

times

greater, Ray and his colleagues found. That translates to six deaths for

every

10,000 people taking erythromycin for the typical two weeks while on the

other

drugs.

" This is an unacceptably high risk, " Ray said.

Nobody realized the magnitude of the problem before, said Dr. Muhamed Saric,

a

cardiologist and director of the electrocardiology laboratory at University

of

Medicine and Dentistry of New Jersey in Newark. " It was thought that

erythromycin is a generally safe drug. "

Most heart doctors knew erythromycin alone carried a slight risk because of

some individual reports on patient deaths, mostly in people who took the drug

intravenously. However, family doctors are less likely to know about it,

Saric

said.

This study, in Thursday's New England Journal of Medicine, was the first to

systematically document the risk. It focused on much more commonly used

erythromycin pills -- usually sold as a generic -- along with certain

medicines

for infections and calcium channel blockers for high blood pressure.

Ray said the danger seems to come from other drugs slowing the breakdown of

erythromycin, which increases its concentration. At high levels it traps salt

inside resting heart muscle cells, prolonging the time until the next

heartbeat

starts, and sometimes triggering an abnormal, potentially fatal, rhythm.

The findings show doctors should choose an alternative antibiotic, Ray said,

at

least when prescribing the drugs that interact. Amoxicillin, another popular

antibiotic, showed no cardiac risk.

" There are other antibiotics that provide the same antimicrobial activity

without building up in the blood the way erythromycin does, " Ray said.

Ray's team of doctors and nurses spent years studying detailed medical

records

of 4,404 Medicaid patients from Tennessee who apparently died of cardiac

arrest

from 1988-93. The team confirmed 1,476 cases of cardiac arrest, then studied

Medicaid's records of each patient's medication use.

Only a small number of patients had taken both erythromycin and any of the

antibiotics or heart drugs carrying a risk.

Still, three of them died. Statistically, it was extremely unlikely those

deaths were due to chance, according to Ray and other experts.

The deaths were in patients taking verapamil or diltiazem, both blood

pressure

drugs sold as generics and also under various brand names: Verelan and

Isoptin

for verapamil, Cardizem and Tiazac for diltiazem.

Other drugs posing a risk with erythromycin, Ray said, include the antibiotic

clarithromycin, sold under the Biaxin brand; fluconazole, or Diflucan, for

vaginal yeast infections; and the antifungal drugs ketoconazole (Nizoral) and

itraconazole (Sporanox). Pills and injections of the drugs, but not topical

forms, carry the risk.

" People may be taking these medications for years, and they develop a throat

infection and someone gives them erythromycin, and that's it, " Saric said.

The AIDS drugs called protease inhibitors and grapefruit juice also should be

avoided, Ray said, because they, too, can boost blood levels of erythromycin.

Erythromycin, in turn, boosts blood levels of verapamil and diltiazem, which

slow heart rate, and thus can worsen abnormal rhythms, said American Heart

Association spokeswoman Dr. Nieca Goldberg. The findings show why people

should

keep a list of medications they take and share them with all their doctors,

said Goldberg, chief of women's cardiac care at Lenox Hill Hospital in New

York

City.

About 340,000 Americans die each year of cardiac arrest, also called sudden

cardiac death, according to the heart association. The condition is caused by

abnormal heart rhythm, usually when the heart begins beating too rapidly or

too

chaotically to efficiently pump blood.

Goldberg noted the once-blockbuster nonsedating allergy drug Seldane was

taken

off the market, in 1998, after reports linking it to sudden cardiac death due

to the same types of abnormal heart rhythms.

The study was funded by the Food and Drug Administration, two other federal

health agencies and the drug company Janssen Pharmaceutica, which makes

Nizoral

and Sporanox. Ray and two other researchers have received consulting fees

from

other pharmaceutical or health products companies.

Copyright 2004 The Associated Press. All rights reserved.

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