Oral erythromycin and the risk of sudden death from cardiac causes

Abstracts on this page have been chosen and edited by Dr Trevor Watts

Abstract

Certain concurrent medications increase plasma erythromycin concentration, sometimes causing tachycardia, ventricular arrhythmias and death.

Main

Ray WA, Murray KT et al. N Engl J Med 2004; 351: 1089–1096

Erythromycin is used in dentistry as one alternative to penicillin, and sometimes for specific indications such as sinusitis. It is metabolized by cytochrome P-450 3A (CYP3A) isozymes, and therefore CYP3A inhibitors (such as calcium-channel blockers, azole antifungals and some antidepressants) potentiate it, increasing the risk of cardiac effects. This study involved a cohort of subjects aged 15-84 yrs (mean 45), with no evidence of life-threatening non-cardiac illness, followed for 1–6 yrs. There were 1,249,943 person-years of follow-up, and 1,476 sudden deaths from cardiac causes.

In patients using erythromycin, the incidence-rate ratio for sudden death was 2.01 times greater than in other subjects (95% CIs: 1.08, 3.75). There was no effect for amoxicillin or the former use of erythromycin. There was a greater effect for the simultaneous use of erythromycin and a CYP3A inhibitor (5.35; 1.72, 16.64) than for those using neither, but current use of amoxicillin and former use of erythromycin gave non-significant ratios. The authors conclude that erythromycin should not be prescribed for patients using CYP3A inhibitors.