Clarithromycin is a popularly prescribed antibiotic used to treat everything from pneumonia to sinus infections.  According to Honor Whiteman of MNT, however, researchers say it may be deadly. She reports on this finding in her article,Commonly prescribed antibiotic ‘could increase risk of cardiac death.’

As reported by Whiteman, this drug is part of a class of antibiotics called macrolides which researchers in Copenhagen, Denmark state can be responsible for abnormal heart rhythms and stroke. Over a period of four years, lead researcher, Anders Hviid, studied more than 5 million Danish adult who were taking antibiotics. They found that patients taking clarithromycin had a greater risk of cardiac death.

However, these researchers do note that the increase in risk is small and do not recommend that doctors stop prescribing this medication to their patients at this time. They suggest that more studies and research be performed to test its suitability for certain patients, particularly those with known heart problems.