Ads for magic antiheartburn drugs seem to be everywhere, telling you to talk to your doctor. You might also talk to your doctor about this study, which suggests those drugs can increase the risk of pneumonia. When they make the stomach less acidic, they also make it more hospitable for microbes, apparently increasing the chance that bugs will spread into your lungs.

What the researchers wanted to know: Do drugs that suppress stomach acid increase the risk of pneumonia?

What they did: The researchers used a database on 500,000 patients of about 150 doctors in the Netherlands. About 20,000 were prescribed acid-suppressive drugs—either H2 receptor antagonists (such as Zantac and Pepcid) or proton pump inhibitors (such as Nexium, Prilosec, and Prevacid). They compared their risk of getting pneumonia with the risk for people who hadn't taken those drugs.

What they found: People who'd taken acid-suppressive drugs were 4.5 times more likely to get pneumonia than people who hadn't taken the drugs. The risk was higher for proton pump inhibitors than for hydrogen receptor antagonists, and higher while people were on the drugs than after they stopped.

What the study means to you: The risk of getting pneumonia, while higher in people on acid-suppressing drugs, is still quite low. This study may be of more concern for those who already have to worry about pneumonia, like people with asthma or the elderly.

Caveats: There were clearly differences between the patients being compared here— some of them had acid reflux problems and the others didn't. There may have been other differences between them, too.

Find out more: Information from the National Library of Medicine's MedlinePlus on heartburn (http://www.nlm.nih.gov/medlineplus/heartburn.html) and H2 receptor antagonists (http://www.nlm.nih.gov/medlineplus/ency/article/002585.htm).

Read the article: Laheij, R.J.F., et al. "Risk of Community-Acquired Pneumonia and Use of Gastric Acid-Suppressive Drugs." Journal of the American Medical Association. Oct. 27, 2004, Vol. 292, No. 16, pp. 1955-1960.

Abstract online: http://jama.ama-assn.org