Antihistamines For Stomach Acid Can Increase C. Diff Infection Risk

Antihistamines for stomach acid are sometimes also called histamine blockers or H2 blockers.  These medications work by inhibiting the production of stomach acid from the cells of the stomach and are used for the treatment of peptic ulcers, gastritis and heartburn. These medication differ from the commonly prescribed antihistamines that are used for allergies or a runny nose. Examples of H2 blockers or antihistamines for stomach acid are Tagamet, Zantac, Axid and Pepcid.
As reported in Medical News Today studies are finding that the use of these H2 blockers, H2 antagonist, or antihistamines are a greater risk of infection from Clostridium difficile.

“Patients receiving antihistamines to suppress stomach acid are at greater risk of infection from Clostridium difficile, or C. diff, a common cause of diarrhea, particularly in health care settings, Mayo Clinic researchers have found. The study focused on histamine 2 receptor antagonists. The researchers found no significant risk for people taking over-the-counter antihistamine drugs, however. The findings appear in the online journal PLOS ONE.

Researchers reviewed 35 observations based on 33 separate studies involving C. diff and antihistamines used for stomach acid suppressive therapy. The researchers found a clear association between histamine 2 receptor antagonists use and C. diff infection. They say it was especially pronounced and caused the greatest risk for hospitalized patients receiving antibiotics. "It's not clear why these antihistamines increase the risk of C. diff infection, because gastric acid does not affect C. diff spores," says senior author Larry Baddour, M.D., a Mayo infectious diseases expert. "However, it may be that vegetative forms of C. diff, which are normally killed by stomach acid, survive due to use of stomach acid suppressors and cause infection."

Researchers say the study highlights the need for judicious use of histamine 2 receptor antagonists in hospitalized patients, and that reducing the use of these drugs could significantly reduce the risk of C. diff infections.”