Calcium-channel blockers are antihypertensives—they keep high blood pressure under control—that also raise the risk of diverticulosis, a bowel problem that causes small bulges or pouches in the intestine. Left untreated, it can lead to diverticulitis, when the pouches become inflamed.
The problem—which affects around 65 per cent of the over-85s—can be life-threatening and may need emergency treatment if the pouches burst or become infected.
Calcium-channel blockers are the only antihypertensives linked to diverticulosis, say researchers from Imperial College London. They also tested ACE inhibitors and beta-blockers by using genetic data from around 750,000 people.
The researchers aren't sure why the drugs should cause diverticulosis but suspect they could be affecting the ability of muscles in the intestine to push food through the gut.
Genetic testing is a relatively new science that allows researchers to assess the benefits and side effects of drugs without having to launch expensive and long trials involving thousands of patients.