Commonly prescribed heartburn drugs may increase the risk of serious kidney damage, new research shows.
Scientists advised patients to use the drugs, known as proton pump inhibitors (PPIs), only when absolutely necessary and not for too long.
PPIs suppress production of acid in the stomach and are used to treat heartburn, acid reflux and gastric ulcers.
Each year millions of people in the UK are treated with the drugs, whose known side effects include nausea, vomiting, abdominal pain, headaches, diarrhoea and constipation.
Researchers who compared patients taking the medicines and histamine H2 blockers, another type of drug that reduces stomach acid, found a strong association between PPIs and declining kidney function.
Over five years PPI users had a 28 per cent increased risk of developing chronic kidney disease and a 96 per cent greater risk of suffering kidney failure.
Patients who took PPIs for longer periods were more likely to experience kidney problems.
Lead scientist Dr Ziyad Al-Aly, from the VA Saint Louis Health Care System in the US, said: “The results emphasise the importance of limiting PPI use to only when it is medically necessary, and also limiting the duration of use to the shortest possible.
“A lot of patients start taking PPIs for a medical condition, and they continue much longer than necessary.”
The research analysed information from national databases of the US Department of Veterans Affairs, identifying 173,321 new users of PPIs and 20,270 new users of histamine H2 receptor blockers.
Each group was followed up to see how their health fared over five years.
In 2013 an estimated 15 million Americans were prescribed PPIs, said the scientists whose findings are reported in the Journal of the American Society of Nephrology.
Five PPIs are licensed for use in the UK: esomeprazole, lansoprazole, omeprazole, pantoprazole and rabeprazole. Omeprazole and pantoprazole can be bought over the counter at pharmacies.