Clarithromycin - an antibiotic used to treat bacterial infections - is associated with an increased risk of heart death, a new study has found.

Clarithromycin belongs to the 'macrolide antibiotics' class of drugs. It works by preventing bacteria from growing.

The authors of the current study say that the absolute risk of heart death due to clarithromycin use is low. Still, more research is needed to understand the link between the drug and heart problems.

For the study, scientists compared the effects of different kinds of antibiotics on heart tissue. They used clarithromycin and another macrolide called roxithromycin, compared with penicillin V, which is known to carry no heart disease risk.

"Our study expands on the available knowledge of the cardiac safety of macrolides, being the first large scale population based observational study to show significantly increased cardiac risk with clarithromycin and the relative cardiac safety of roxithromycin," the authors said, according to a news release.

The researchers used data available on 160,297 courses of clarithromycin, 588,988 of roxithromycin and 4,355,309 of penicillin V. The medications were prescribed to adults in Denmark between 1997 and 2011, The Telegraph reported.

During the study period, there were 285 cardiac deaths, 32 of which were during use of roxithromycin, while 18 during use of clarithromycin.

According to the team, a total of 37 cardiac deaths occured per one million courses of clarithromycin when compared to penicillin in the Dutch population, the Telegraph reported.

The researchers said, "Clarithromycin is one of the more commonly used antibiotics in many countries and many millions of people are prescribed this drug each year; thus, the total number of excess (potentially avoidable) cardiac deaths may not be negligible."

The study is published in the British Medical Journal.