A team of researchers led by Dundee University have warned that taking a common antibiotic could lead to heart problems.
Clarithromycin is widely prescribed for treating lower respiratory tract infections like pneumonia and the sudden worsening of chronic obstructive pulmonary disease (COPD).
Previous studies have suggested that cardiovascular events such as heart failure, heart rhythm problems or sudden cardiac death may be increased during treatment with the drug, but the long-term effects are still unclear.
The university and its partners studied 3,000 patients who had been given at least one dose of clarithromycin during a stay in hospital and compared them to patients who had not received antibiotics.
In the following year cardiovascular events were recorded in 26% of the patients who had COPD and were given clarithromycin, against 18% of those not given a dose.
For patients with pneumonia 12% of those on the drug had a heart problem compared to 7% not treated with it.
The data also suggests that the increased risk may persist beyond the time when clarithromycin is stopped, possibly due to its effect on the body’s inflammatory process in patients with chronic lung conditions.
The researchers are not recommending any change in the prescribing of clarithromycin at this stage, saying their findings need to be validated by further studies.