Three-Month Antibiotic Treatment Reduces Risk Of Future Heart Attack

The antibiotic clarithromycin significantly lowered risk of death or serious cardiovascular events compared to those given a placebo. Clarithromycin is typically prescribed for respiratory infections.

“Patients with acute heart attacks or severe angina seem to benefit from treatment with a macrolide antibiotic,” says lead author Juha Sinisalo, M.D., of Helsinki University Central Hospital in Helsinki, Finland. “The most likely mechanism of action is clarithromycin’s antibacterial effect.”

Infections are one cause of inflammation, and inflammation plays an important role in the development of coronary heart disease. Increasing evidence from animal and human studies indicates that several infections such as Chlamydia pneumoniae are associated with coronary heart disease.

Although the apparent advantage of clarithromycin likely stems from its antibacterial power, the drug may do double duty in coronary heart disease patients. Clarithromycin also has an anti-inflammatory action that is independent of its effect on bacteria, he says.

“There are only two ways to prove the connection between infections and coronary artery disease: vaccinations and antibiotic therapy,” says Sinisalo. “Vaccinations to prevent heart disease are not available. Therefore, we conducted this study to find out if suppressing infections would decrease the rate of new heart attacks.”

Researchers have published results from only a few studies that have tested antibiotics for patients with a high risk of heart attack. Trials in patients with stable heart disease have yielded differing results. In a previous randomized study, a macrolide antibiotic was used for one month to treat people with acute coronary problems. The antibiotic seemed to show some benefit when compared to a placebo, but that advantage disappeared within six months.

Sinisalo and his colleagues studied 148 patients, ages 18 to 80, who were admitted to nine hospitals in different parts of Finland between September 1998 and December 2000. These patients had either a serious heart attack or severe chest pain.