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Research published in the September 9, 2004 New England Journal of Medicine reported that patients using the widely prescribed antibiotic erythromycin had an increased risk of death from cardiac causes compared to patients not taking antibiotics.
Erythromycin, a valuable antibiotic when used appropriately, has been available in the U.S. for over 40 years and is considered not to cause serious adverse reactions. However, over the years there have been reports in the medical literature of a...
Research published in the September 9, 2004 New England Journal of Medicine reported that patients using the widely prescribed antibiotic erythromycin had an increased risk of death from cardiac causes compared to patients not taking antibiotics.
Erythromycin, a valuable antibiotic when used appropriately, has been available in the U.S. for over 40 years and is considered not to cause serious adverse reactions. However, over the years there have been reports in the medical literature of a change in electrical conduction in the heart that can increase the risk of a potentially fatal heart rhythm disturbance known as torsades de pointes. These reports often have involved the injectable form of erythromycin.
The New England Journal of Medicine study was conducted by researchers from Vanderbilt University School of Medicine and the Nashville, TN Veterans Affairs Medical Center. The study was primarily supported by grants from the U.S. government’s Agency for Healthcare Research and Quality, Centers for Education and Research on Therapeutics, and the Food and Drug Administration.
The observational research study examined the medical records of a large group of Tennessee Medicaid enrollees. Prescriptions for erythromycin and the antibiotic amoxicillin were identified from computerized pharmacy files. Amoxicillin was used as the control antibiotic because it had not been associated with heart rhythm disturbances.
The researchers were also interested in drugs that the Medicaid enrollees were taking together with erythromycin that could result in clinically significant drug interactions. The antifungal drugs ketoconazole (NIZORAL), itraconazole (SPORANOX), and fluconazole (DIFLUCAN); the heart drugs diltiazem (CARDIZEM, DILACOR) and verapamil (CALAN, ISOPTIN); troleandomycin (TAO) and older antibiotics; and the antidepressant nefazodone (SERZONE) were identified as drugs that could increase the levels of erythromycin in the body and increase the risk of heart rhythm disturbances. The high blood pressure drug mibefradil (POSICOR) was also identified as a potentially dangerous interacting drug, but it was removed from the market for safety reasons in 1998 (see Worst Pills, Best Pills News July 1998).
In the final analyses of the study, it was found that the rate of sudden death from cardiac causes among enrollees using erythromycin at the time of death was twice as high as that among those who had not used antibiotics.
There was no statistically significant increase in the risk of sudden death among those who had used erythromycin in the past or among those who were currently using amoxicillin.
The rate of sudden death was increased by a factor of five in those individuals who took erythromycin together with one of the interacting drugs listed above, compared to those who had not used one of the interacting drugs or an antibiotic. However, there was no increase in the risk of sudden death in those who took amoxicillin together with one of the drugs that interacts with erythromycin. In addition, there was no increase in those who had previously used antibiotics and one of the interacting drugs.
The researchers concluded by saying:
... patients who used both erythromycin and the study CYP3A inhibitors [the interacting drugs listed in the article] had a risk of sudden death from cardiac causes that was five times as great as that among patients who had not used these drugs. Given that there are alternatives to erythromycin and to most CYP3A inhibitors, the use of this combination should be avoided in clinical practice.
We agree.
This study underscores several important points: (1) research on the safety of older drugs is extremely valuable; (2) no drug is totally “safe” — even an old standby like erythromycin; and (3) the answers to important safety questions about drugs require government funding.
What You Can Do
You should not take erythromycin in combination with one of the interacting drugs listed in this article. If you are, you should contact your physician immediately. As mentioned above, erythromycin is an important antibiotic when used appropriately. Therefore, we do not recommend against its use when it is not used with one of these interacting drugs.
