Two studies suggest a possible link between popular heartburn medications like Nexium and Prilosec and an increased risk of kidney disease.

The studies examined the effects of these proton pump inhibitors, or PPIs, on patient’s risk of developing kidney problems. These medications work by reducing the amount of acid produced in the stomach.

One of the studies, led by Dr. Pradeep Arora of the SUNY Buffalo School of Medicine and Biomedical Science, looked at the history of over 24,000 persons who developed chronic kidney disease over a seven-year period.

Researchers found that one-fourth of those patients had previously been treated with a PPI. They also found that patients taking a PPI had nearly twice the risk of premature death.

The second study was a cooperative effort between Australian and U.S. researchers. Among a population of over 10,000 patients, they found that users of PPIs were up to 50 percent more likely to develop chronic kidney disease.

The researchers also noted that they did not see a similar increase in kidney disease among users of a different class of heartburn medications called H2-blockers.

Symptoms of Chronic Kidney Disease

In chronic kidney disease, the kidneys’ ability to remove waste products from the blood gradually decreases. Like the condition itself, its symptoms develop progressively over time.

Initially, they may experience an excessive need to urinate at night. As metabolic wastes build up in the blood, patients may feel weak, lethargic or less mentally alert.

They may also experience nausea, vomiting, loss of appetite, or shortness of breath.

More advanced kidney disease can cause serious secondary conditions like anemia, lowered resistance to infections, damage to muscles and nerves, encephalopathy, or heart failure.

If kidney disease occurs in the presence of certain other conditions, the formation and support of bone tissue may also be impaired. Gout may result from higher levels of uric acid.

Treatment at the more advanced levels of disease may require dialysis or kidney transplantation.

What Links PPIs to Kidney Disease?

These findings are still considered relatively new. Doctors have a few theories that may explain the relationship between kidney disease and PPIs.

One theory is that these drugs can cause a shortage of magnesium, which can lead to kidney damage.

Another theory is that over time, short-term use of PPIs can cause repeated episodes of acute interstitial nephritis, which itself can contribute to kidney damage.

Other theories suggest the observed kidney problems may be related to other causes that tend to co-occur in patients who take PPIs.

Based on these possible Prilosec and Nexium side effects, Dr. Arora suggests that physicians in general have been overprescribing PPIs. He says patients should take PPIs only for serious gastrointestinal conditions like gastroesophageal reflux disease.

Dr. Arora’s suggestion is consistent with the FDA’s approved uses for PPIs, but the way physicians have been prescribing these drugs seems to follow a different set of priorities.

According to Dr. Arora, 90 percent of prescriptions written for PPIs in the U.S. are not issued for an FDA-approved use of those drugs.