Clarithromycin use is linked to a significant increase in the risk of cardiac death, compared with penicillin, particularly among women, according to findings from a large Danish cohort study, which also found that roxithromycin carried no such increased risk.
Analysis of registry data from more than 5 million Danish adults prescribed 7-day courses of clarithromycin (n = 160,297), roxithromycin (n = 588,988), or penicillin V (n = 4,355,309) showed an overall 76% increase in the risk of cardiac death associated with clarithromycin. The risk was increased nearly threefold in women (adjusted rate ratio, 2.83), and it was a nonsignificant 4% higher in men, reported Henrik Svanström and his colleagues from the Statens Serum Institut, Copenhagen.
The researchers found no effect of age or concomitant use of cytochrome P450 3A inhibiting drugs on the risk of cardiac death. However, the study could not rule out confounding by lifestyle and health factors such as smoking and body mass index, they said in their report, which was published online Aug. 19 in BMJ (2014;349:g4930 [doi: 10.1136/bmj.g4930]).
"In absolute terms, 37 (95% confidence interval, 4-90) excess cardiac deaths occurred per 1 million treatment courses associated with current use of clarithromycin, compared with current penicillin V use in this study," the investigators wrote.
Mr. Svanström and his associates declared that they had no financial conflicts of interest relevant to this research.