The FDA is advising caution before prescribing the antibiotic clarithromycin (Biaxin) to patients with heart disease because of a potential increased risk of heart problems or death that can occur years later. The FDAs recommendation is based on a review of the results of a 10-year follow-up study of patients with coronary heart disease from a large clinical trial that first observed this safety issue.
The large clinical trial, called the CLARICOR trial, observed an unexpected increase in deaths among patients with coronary heart disease who received a two-week course of clarithromycin that became apparent after patients had been followed for one year or longer. There is no clear explanation for how clarithromycin would lead to more deaths than placebo. Some observational studies also found an increase in deaths or other serious heart-related problems, while others did not. All the studies had limitations in how they were designed. Of the six observational studies published to date in patients with or without coronary artery disease, two found evidence of long-term risks from clarithromycin, and four did not. Overall, results from the prospective, placebo-controlled CLARICOR trial provide the strongest evidence of the increase in risk compared to the observational study results. Based on these studies, the FDA is unable to determine why the risk of death is greater for patients with heart disease.
As a result, the FDA has added a new warning about this increased risk of death in patients with heart disease, and advised prescribers to consider using other antibiotics in such patients. FDA also added the study results to the clarithromycin drug labels. As part of the FDA’s usual ongoing safety monitoring of drugs, they are continuing to monitor safety reports in patients taking clarithromycin.