The Food and Drug Administration has issued an ALERT, a Patient Information Sheet, and Healthcare Professional Information regarding a Danish study (the CLARICOR study) of patients with heart disease reporting increased mortality in those treated with clarithromycin (14 days) compared with patients who received a placebo.
The FDA states that: “The observed difference in mortality became apparent after patients had been followed for one year or longer after the study drug was given. A mechanism by which two-weeks of clarithromycin could cause increased mortality measured after one year or longer is not clear.
The study (http://bmj.bmjjournals.com/cgi/rapidpdf/bmj.38666.653600.55v1), published in the British Medical Journal, was conducted by academic investigators in Denmark, and designed “to evaluate whether treatment with clarithromycin could prevent another event (heart attack, unstable angina, or death) in patients with stable coronary artery (heart) disease (CAD).”
In this study, over 4300 people with stable CAD received either clarithromycin (500 mg once daily) or a placebo for two weeks. Analysis of all cause mortality found that there were 212 deaths in the clarithromycin group and 172 deaths in the placebo group.
The FDA notes that “the observed differences in deaths became apparent about one year or longer after the study drug was given. The finding of a higher mortality rate occurring beyond one year of follow-up after a single two-week course of clarithromycin was an unexpected finding.”
Most of these deaths were attributed to heart disease. “When the analysis was limited to cardiovascular deaths, the difference in mortality between treatment groups was still present. There is no clear explanation for how clarithromycin would lead to more deaths than placebo and no biological mechanism to account for deaths occurring one year or longer after a single two-week treatment course of clarithromycin in the CLARICOR study.”
Although additional research will be needed to investigate this unusual result and there may be explanations for the higher death rate that are not associated with the drug itself, the FDA has issued the ALERT (http://www.fda.gov/cder/drug/infopage/clarithromycin/default.htm),.
Patient Information Sheet (http://www.fda.gov/cder/drug/InfoSheets/patient/clarithromycinPIS.htm), and Healthcare Professional Information(http://www.fda.gov/cder/drug/InfoSheets/HCP/clarithromycinHCP.htm) as a precautionary measure.
Clarithromycin is in a class of medicines called macrolide antibiotics and is used to treat bacterial infections in many parts of the body such as the ears, throat, lungs, sinuses, and skin.
It is used in combination with other medicines to treat stomach ulcers caused by bacteria. It is also used for the treatment and prevention of certain types of mycobacterial infections. Clarithromycin does not work for viral infections such as the common cold or flu.
Clarithromycin should not be taken by people who are allergic to clarithromycin or any of the other macrolide antibiotics such as erythromycin or azithromycin.
The drug, made by Abbott Laboratories is marketed as BIAXIN® and BIAXIN® XL. At present, no specific changes in the product labeling for clarithromycin are being recommended.
Abbott Labs maintains that the drug has proven safe over the course of years of research and that it regards the study results as a “random finding.”