Some £100m from the NHS budget has been spent unnecessarily on drugs to treat indigestion, say two gastroenterology doctors at King's College Hospital, London.
Proton pump inhibitors that block the backflow of stomach acid are frequently prescribed for indigestion.
In 2006, £425m was spent on proton pump inhibitors in England alone and £7bn worldwide.
The King's College doctors, writing in the British Medical Journal (BMJ), say effective and less expensive alternative drugs are available for many patients, yet are superseded by prescriptions for proton pump inhibitors, which now account for over 90% of the NHS drug budget for treating dyspepsia.
In primary care, a Swedish study of patients who had been taking proton pump inhibitors for four years showed 27% were able to discontinue the drug altogether.
The authors also point to an audit of patients admitted as a medical emergency to a hospital in Wales, which found that a quarter were taking proton pump inhibitors, but in only half of the patients was the drug deemed appropriate.
The authors say that these drugs reflect a huge advance in therapeutic medicine and have transformed patients' lives, but it is clear they are being overused.