The Food and Drug Administration cautioned Tuesday against prolonged use or high dosages of the family of acid reducers called proton pump inhibitors, a family that includes such well-known drugs as Nexium, Prilosec, Prevacid and Protonix. The agency said it would order revised labeling on packages of the drugs to reflect the fact that they have been associated with an increased risk of fractures of the hip, wrist and spine.
Other drugs in the family include Losec, Zegerid, Aciphex and omeprazole. An estimated 113.4 million prescriptions for the drugs are written each year and large numbers are sold over the counter.
The drugs block the production of acid in the stomach and provide important benefits for many people with conditions such as erosive esophagitis, nonsteroidal anti-inflammatory drug-induced ulcers and gastroesophageal reflux disease. But most people take them primarily to control heartburn.
The drugs have previously been linked to an increased risk of contracting pneumonia and the troublesome bacterium Clostridium difficile, as well as to an increased risk of dementia. A recent study found that the drugs increase the risk of bone fractures by about a quarter.
In its new warning, the agency said that it had reviewed seven studies and six of them had found an increased risk of bone fractures. The risk apparently increased with higher dosages and longer uses, and the greatest danger was in those over 50 years of age.
It is not clear what the mechanism of the increased fractures is. Most researchers believe it is due to decreased absorption of calcium from the diet because of the reduced stomach acid, but it is possible that the drugs interfere with bone maintenance. Two newer drugs, esomeprazole and dexlansoprazole are now being evaluated specifically for their effects on bone and results are expected by the end of 2011.
-- Thomas H. Maugh II