There was a recent article in the Independent that in a new analysis of patient data carried out by Danish researchers, the drug was found to cause 37 potentially avoidable deaths compared to similar antibiotics for every one million courses of the antibiotic prescribed. Although the risk is small further evaluation is urgently required.

Clarithromycin belongs to a group of antibiotics known as macrolides. These antibiotics are known to affect the rhythm of the heart muscle’s electrical activity and are therefore thought to increase the risk of potentially fatal heart rhythm problems.

The Danish researchers, from the Statens Serum Institut in Copenhagen, analysed more than five million patients treated with three different antibiotics to determine the differing risks of each. Individuals with serious disease were excluded from the analysis.

They said that because the absolute risk was so small, it was unlikely that prescribing practice would have to change. However, they 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 cardiac deaths may not be negligible”.

After adjusting for factors such as age, sex, cardiac risk and use of other medication, ongoing use of clarithromycin was associated with a 76 per cent higher risk of death from heart disease compared with use of penicillin V. The study was published in the British Medical Journal.

“More research is now needed to understand the effect of this antibiotic on the wider population. The bottom line is no one should be taking antibiotics unless they absolutely have to and doctors should give careful consideration before prescribing them.”

The authors of the study said that “confirmation in independent populations is an urgent priority given the widespread use of macrolide antibiotics”.