Sept. 18 (HealthDay News) -- A popular stomach acid reducer greatly increases the risk of pneumonia in certain critically ill hospital patients, a new study has found.

Researchers at Wake Forest University School of Medicine in North Carolina analyzed the charts of 834 cardiothoracic surgery patients on breathing machines who were given stomach acid reducers to prevent stress ulcers. The patients were given either ranitidine (Zantac) or pantoprazole (Protonix). Both drugs reduce stomach acid, but pantoprazole is more powerful and is the drug of choice in many hospitals.

However, the study found that people given pantoprazole were three times more likely to develop hospital-acquired pneumonia than those given ranitidine. The findings were published recently in Chest.

"We conducted this study, in part, because we thought we were seeing more pneumonias than we were used to having," Marc G. Reichert, pharmacy coordinator for surgery at Wake Forest University Baptist Medical Center and a co-author of the study, said in a university news release.

Hospital-acquired pneumonia -- the leading cause of infection-related deaths in critically ill patients -- increases hospital stays by an average of seven to nine days, adds to the overall costs of care and raises the risk for other complications.

People on breathing machines sometimes develop pneumonia when stomach secretions reflux into the lungs.

SOURCE: Wake Forest University School of Medicine, news release, Sept. 14, 2009