Azithromycin raises risk of CV death

DESPITE being previously considered to have low cardiotoxicity, the antibiotic azithromycin has now been found to raise the absolute risk of both cardiovascular and all-cause mortality, a study shows.

Compared with patients who took amoxycillin, patients who took azithromycin for five days had a “small” but significant increased risk of death – and that risk was much higher among patients with the most cardiovascular risk factors at baseline.

Azithromycin was associated with an extra 47 cardiovascular deaths per million overall, and 245 additional cardiovascular deaths per million among the patients in the highest decile for cardiovascular disease risk.

Patients taking levofloxacin had a similarly increased risk of cardiovascular death but amoxycillin was not associated with any increased risk of death.

The large observational study used Medicaid data collected between 1992 and 2006 in Tennessee to compare mortality between patients on five days of azithromycin therapy, those prescribed amoxycillin, ciproflaxacin, levoflaxacin, and those not taking any antibiotics.

The cohort included about 2 million prescriptions for the various antibiotics, with amoxycillin being the most common, along with more than 1.3 million controls not taking antibiotics.

The data came from patients aged 30 to 74 years who had no life-threatening non-cardiovascular illness, had not received a diagnosis of drug abuse or resided in a nursing home in the previous year,and had not been hospitalised in the prior 30 days.

For the 10-day period after the prescription was filled, azithromycin use was associated with an 86% increased risk of cardiovascular death but the risk of death from any cause was not significantly increased, the authors wrote.

New Eng J Med 2012; 366:1881-90