Cardiovascular risks associated with clarithromycin

Concerns about the cardiovascular risks of macrolide antibiotics surfaced in the 1980s, with case reports and clinical studies describing arrhythmias and QT prolongation with erythromycin.1 2 These concerns subsequently extended to azithromycin3 and clarithromycin,4 two other members of the macrolide class. For example, a large cohort study using Danish healthcare data showed, on average, a 76% higher risk of cardiovascular mortality with current use of clarithromycin compared with penicillin V among middle aged patients, translating into an adjusted absolute risk difference of 37 cardiac deaths per million courses.4 The authors acknowledged concerns about confounding by indication and residual confounding. However, in a randomised controlled trial without such problems, a two week course of clarithromycin increased the risk of cardiovascular death for three years, compared with placebo, among patients with stable coronary artery disease.5

The study by Wong and colleagues in this issue6 further characterises …