The Food and Drug Administration is warning consumers today that certain stomach acid drugs may increase the risk of a serious intestinal bacteria infection.

The drugs, including Nexium, Prilosec, Prevacid, Zegerid and others, fall into a category called proton pump inhibitors (PPIs). They are prescribed to treat acid reflux, stomach ulcers and other conditions, and work by reducing the amount of acid in the stomach.

The bacterial illness is called Clostridium difficile–associated diarrhea (CDAD), and its main symptom is diarrhea that does not improve, according to an FDA statement. The bacteria are commonly referred to as “C. diff.”

“Stomach acid is a very important defense mechanism against pathogens. It kills them,” said Dr. Edith R. Lederman, who authored a study published in October linking C. diff infections to stomach acid drugs, in an interview with MyHealthNewsDaily at the time.

Patients taking PPIs who develop diarrhea that does not improve may have CDAD, according to the FDA. The agency is working with manufacturers to include information in the drug labels about the increased risk with use of PPIs. PPIs are the third highest-selling class of drugs in the U.S., according to 2010 findings from Consumer Reports.

Lederman's study, published in the journal Clinical Infectious Diseases, showed nearly half of 485 patients hospitalized at a medical center over a four-year period who had C. difficile infections had previously been prescribed an acid suppressing drug, most of which were either proton-pump inhibitors (PPIs), such as Prilosec and Prevacid, or histamine-2 antagonists, such as Tagamet and Zantac.

The FDA is also reviewing the risk of CDAD in users of histamine H2 receptor blockers.

The elderly, and people with certain medical problems, generally have the greatest chance of developing C. diff infections, according to the Centers for Disease Control and Prevention. The infection can spread in hospitals because C. diff spores can live outside the human body for a very long time, and may be found on items such as bed linens, bed rails, bathroom fixtures and medical equipment.

There are antibiotics that can be used to treat C. diff, according to the CDC, but in some severe cases, surgery to remove the infected part of the intestines may be needed.

In Lederman's study, 23 patients died from their C. diff infections; 19 of them had taken prescription acid suppressants during the 90 days before their hospital stay.

Hand washing, alcohol-based sanitizers, and taking only antibiotics that are prescribed by a doctor can lower a person's risk of getting or spreading C. diff, according to the CDC.

Pass it on: People taking drugs that suppress stomach acid production may be at an increased risk for intestinal bacteria infections.

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