More evidence links heartburn drugs to serious kidney problems

People taking common heartburn medications known as proton pump inhibitors (PPIs) are at increased risk of new and severe kidney disease, according to a U.S. study.

Among hundreds of thousands of patients in Department of Veterans Affairs (VA) databases, new users of PPIs without kidney disease were 30 percent more likely to develop chronic kidney disease over the course of five years. Their risk of kidney failure was doubled.

PPIs like Nexium and Prevacid are prescribed to treat ulcers, heartburn and acid reflux and are some of the most effective forms of treatment available, the study authors write in the Journal of the American Society of Nephrology.

These drugs are generally viewed as safe and may be overprescribed and continued for long periods without being necessary, they note.

"We suggest judicious use of PPI, and that use be limited to when it is medically necessary and to the shortest duration possible," said senior author Dr. Ziyad Al-Aly, associate chief of staff for research and education at the VA Saint Louis Health Care System.

The study team analyzed data in national VA databases on 20,270 people who had recently started taking PPIs. They compared this group to 173,321 people who had started taking H2 blockers, a group of drugs that reduce stomach acid by a different mechanism, blocking histamines in the stomach.

All patients were free of kidney problems at the start, and were followed for five years to see if their kidney function changed.

After adjusting for personal, social and economic factors as well as health conditions that could influence kidney disease risk, the study team found that people taking PPIs were at significantly higher risk of new kidney problems compared to those taking H2 blockers.

The risk of a decline in kidney function was 32 percent higher for people taking PPIs and the risk of new cases of chronic kidney disease was 28 percent higher.

Patients taking PPIs were 96 percent more likely to experience end-stage renal disease - kidney failure - than those who took H2 blockers.

The risks also increased with the time that someone was taking PPIs, leveling off after about two years of use.

Because many PPIs are available over the counter, people may take them without the input of a doctor, Al-Aly said. He recommends limiting the use of over the counter PPIs to only times when it is necessary.

"If people find themselves taking over the counter PPI frequently, then a doctor consultation is definitely needed to determine best and safest options available to that patient," Al-Aly told Reuters Health by email.

H2 blockers are much less likely to cause kidney problems but often aren't as effective as PPIs, said Dr. David Juurlink, a clinical pharmacologist and drug safety researcher at the University of Toronto, said by email.

"For many patients, dietary modification (less fat and alcohol) would make acid-lowering drugs unnecessary and would impart other long-term benefits as well," said Juurlink, who was not involved in the study.

"Patients should appreciate that, like all drugs, PPIs carry risk. The fact that they're available over the counter doesn't mean they're safe," Juurlink said. "People who take PPIs and are later found to have kidney problems should ask their physicians whether the drugs might be playing a role," he advised.