Proton pump inhibitors like Nexium, Prilosec, Prevacid, and Zegerid that are commonly used to treat heartburn and acid reflux have been found to increase the likelihood of kidney failure in older users, a new study has found."Generally, the drugs are very well tolerated, and the vast majority of patients who take them will not develop [kidney failure] or other serious problems," said lead study author Tony Antoniou, a researcher at the Institute for Clinical Evaluative Sciences and St. Michael's Hospital in Toronto, Reuters reported "But the drugs should be used for the shortest possible duration," he added.The study, published Monday in the journal JAMA Internal Medicine, involved roughly 290,000 people over the age of 66 who were taking PPIs while living in Ontario between 2002 and 2011. A similar number of people not taking the drugs were also observed."Acute kidney injury occurred in 1,787 people, substantially less than 1% of the total study population. People taking proton pump inhibitors had a hospitalization rate of 13.49 per 1,000 persons per year, compared with 5.46 per 1,000 without the drugs," Reuters reported.In short, the researchers observed the rates of kidney failure in the first 120 days that a person began taking the drugs. The researchers excluded people who had taken them in the past, people with HIV and lupus, as well as people who had been prescribed antibiotics in the last four months.Based on the results, Dr. John O'Brian Clarke, a gastroenterologist at the Johns Hopkins Hospital in Baltimore, said, "I would not restrict proton pump inhibitors based on this study alone; the overall risk of [kidney failure] in the study population was still quite low and the association with proton pump inhibitors and renal injury is still only an association."Nonetheless, "This study supports a growing body of literature to suggest that proton pump inhibitor use is not risk-free," Clarke said. "Clinicians should make every effort to restrict these agents only to patients who truly need proton pump inhibitor therapy and to find the minimum dose and duration of therapy necessary to treat their issues." CBS News reported that roughly 15 million Americans use PPIs as of 2013. According to The Washington Post , "studies have shown that as many as 70 percent of those people don't need them and 25 percent who use them long-term could stop without developing symptoms."