Clarithromycin is a macrolide antibiotic medication prescribed to patients with respiratory tract infections. Previously, some clinical trials have found that clarithromycin may also have effects on cardiovascular outcomes in patients with cardiovascular disease. This study aims to investigate the relationship between the use of clarithromycin and the risk of cardiovascular outcomes.

This population-based study included a total of 326,781 patients aged 18 years or more who were receiving oral clarithromycin (n=108,988) or amoxicillin (n=217,793). The effect of clarithromycin and amoxicillin use on cardiovascular outcomes was examined. The primary outcome of the study was myocardial infarction, along with all-cause mortality, cardiac mortality, arrhythmia, and stroke.

The adjusted rate ratio of myocardial infarction (MI) was 3.66 14 days after starting the antibiotic treatment. The rate of MI was 44.4 per 1,000 person-years with clarithromycin and 19.2 per 1,000 person-years with amoxicillin. The same trends were observed for other outcomes as well, with stroke being the only expectation. The adjusted absolute risk difference for the use of clarithromycin vs. amoxicillin was 1.90 MI events per 1,000 patients.

The research concluded that patients consuming clarithromycin were at a higher risk of myocardial infarction and other cardiovascular outcomes like arrhythmia and cardiac mortality.