Clinical Question: In patients with stable coronary heart disease, does clarithromycin (Biaxin) treatment decrease bad outcomes?

Setting: Outpatient (any)

Study Design: Randomized controlled trial (double-blinded)

Allocation: Concealed

Synopsis: Since Chlamydia pneumoniae has been isolated from atherosclerotic tissue, researchers have explored the use of antibiotic treatment of patients with coronary heart disease. Danish researchers identified all 13,702 patients in the Copenhagen, Denmark area diagnosed with myocardial infarction or angina pectoris, then randomized 4,373 of these patients, using concealed allocation, for this study. The patients were treated with oral clarithromycin 500 mg once daily or placebo for two weeks. Over an average of three years, the combined outcome of all-cause mortality or myocardial infarction was not different between the two groups (15.8 percent with clarithromycin versus 13.8 percent with placebo). However, the individual outcome of all-cause mortality was significantly higher in the antibiotic group (9.8 versus 7.8 percent; P = .03). This increase in the death rate was because of a significant increase in cardiovascular mortality (5.1 versus 3.5 percent; P = .01). In addition, adverse events were significantly more common in the pateints treated with clarithromycin.

Bottom Line: The theory of a bacterial cause of heart disease is rapidly deflating. Using the antibiotic clarithromycin in patients with coronary heart disease is not beneficial and may be harmful, with one additional death for every 50 patients who receive clarithromycin. Two other studies also have shown a slight increase in mortality with antibiotic therapy; taken together, these three studies show a 28 percent increase in mortality with clarithromycin (odds ratio = 1.28; 95% confidence interval, 1.05 to 1.57). (Level of Evidence: 1b)

Used with permission from Shaughnessy AF. Clarithromycin ineffective in CHD. Accessed February 10, 2006, at: http://www.InfoPOEMs.com.