Certain proton pump inhibitor drugs designed to treat acid reflux have been linked to an increase in pneumonia. Some of those associated with the higher risk included Nexium, Prilosec, and Prevacid.
Dr. Shoshana J. Herzig, chief medical resident at Beth Israel Deaconess Medical Center in Boston, is referenced in the NY Times’ article about acid reflux drugs and pneumonia. According to Herzig, the acid reflux drug suppress stomach acid but may promote the growth of another bacteria in the upper gastrointestinal and upper respiratory tracts. This may be the source of the increased in pneumonia for those taking the acid reflux drugs.
Other acid reflux drugs, notaby Pepcid and Zantac aren’t associated with the increased pneumonia risk because they are histamine-2 receptor antagonists.