Proton Pump Inhibitors Affect Gut Bacteria, Which May Fuel Infection

By Kathryn Doyle

December 21, 2015

(Reuters Health) - Proton pump inhibitors (PPI) used to reduce stomach acid and treat acid reflux change the populations of microbes living in the intestines, which may help explain why they increase the risk of certain infections, according to a new study.

PPIs are among the top 10 most widely used drugs in the world. They may cause side effects like diarrhea, nausea and vomiting, and some studies have linked them with an increased risk of the Clostridium difficile infection.

"I think mostly general practitioners and medical doctors should be aware of these side effects," said lead author Floris Imhann of the University of Groningen and University Medical Center Groningen in the Netherlands.

"Individual risk (of C. diff) is fairly low," but PPIs are widely used, and often overused, Imhann told Reuters Health by phone.

The researchers analyzed the gut microbiome of 1,815 adults in the Netherlands, some who were healthy and some with gastrointestinal disorders.

Participants reported their current medication use and gut complaints in a questionnaire and provided stool samples for microbial DNA analysis.

Just over 10% of the participants said they were using a PPI, including 8% of the healthy general population and 20% of those with inflammatory bowel disease. PPI users tended to be older and have a higher body mass index than others.

Those using PPIs had less diversity of their gut microbes, the researchers reported online December 9 in the journal Gut.

"The differences between PPI users and non-users observed in this study are consistently associated with changes towards a less healthy gut microbiome," they note. "These differences are in line with known changes that predispose to C. difficile infections and can potentially explain the increased risk of enteric infections in PPI users."

"On a population level, the effects of PPI are more prominent than the effects of antibiotics or other commonly used drugs," the researchers point out.

"These PPIs, they are very good drugs, they work really well," said senior author Dr. Rinse K. Weersma. But many people take them over the counter and about half the time, they're not being taken appropriately, he said.

According to this study, people who take the drugs have beneficial bacteria in lower numbers and more harmful bacteria in higher numbers, he said.

"Once they are started most people do not think about stopping them," Weersma told Reuters Health by phone.

In the Netherlands, PPIs are very widely used, and antibiotics are not as common as in the U.S., so PPIs cause a greater disturbance to the microbiome, Imhann said.

PPI use makes some infections 1.5 times as likely, he said.

"Knowledge is lacking there, the perception is still that they're relatively safe," Weersma said.


Gut 2015.


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