Antacid drugs linked to vitamin B-12 deficiency

For acid indigestion, millions of Americans find relief in the antacids they keep in their medicine cabinets. But a Kaiser Permanente study released Tuesday provides a new reason to feel heartburn.

Kaiser researchers have linked long-term use of a popular type of antacid medication to vitamin B-12 deficiency, a condition that when left untreated can increase the risk of dementia, nerve damage, anemia and other potentially serious medical problems.

The study, the first large-scale look at indigestion relief medication, was published online Tuesday in the Journal of the American Medical Association.

It found study participants who took a class of drugs known as proton pump inhibitors - sold under brand names such as Prilosec, Prevacid and Nexium - for more than two years had a 65 percent increased risk of B-12 deficiency.

Prescription and OTC

"It's not that people should stop the medication," said Dr. Douglas Corley, a Kaiser gastroenterologist and the senior researcher on the study. "It raises the question of whether they should check with their physician to be screened for this vitamin deficiency."

Proton pump inhibitors are among the most commonly prescribed medications in the United States, accounting for more than 100 million prescriptions a year and about $14 billion in sales. While many are available by prescription only, some of these drugs, including Prilosec and Prevacid, are sold over the counter at lower doses.

The drugs, which became popular in the 1990s, are commonly used to treat heartburn, stomach acid reflux disease and gastric ulcers. They are typically recommended for short-term use - up to eight weeks - but some people take the drugs for years.

Alfred Dobrow, 64, a retired ophthalmologist, has taken these antacid medications, mainly Prilosec, for 15 years to treat his acid reflux, a problem that affects as many as 4 in 10 Americans. He said the new class of drug changed his life because antacids like Rolaids and Tums didn't work.

The San Francisco resident said he's not seriously worried about developing B-12 deficiency because he takes a multivitamin with more than the recommended dose of B-12. But he's concerned about the widespread use of the drugs, especially among people who are not being monitored by a physician.

Acid suppressant

"Now you can go to Costco and get a barrelful of them for almost nothing," he said. The widespread access may falsely reassure people that the drugs are completely benign, he added.

In fact, the acid suppressants have been linked in past research to increased risk in food-borne infections and bone fractures because these drugs make it difficult to absorb certain nutrients, Corley said.

Unlike chewable antacids like Tums, which work to neutralize stomach acid after it has already formed, these drugs go after the source. They shut down the cells in the stomach responsible for producing acid so they can no longer do their job.

"But the same cell that makes stomach acid also makes a little protein that helps vitamin B-12 be absorbed," said Corley, explaining how vitamin B-12 would be considered an unintentional casualty in the process.

While a few smaller studies on older patients demonstrated the B-12 connection, the Kaiser researchers reviewed the records of nearly 26,000 adult patients diagnosed with vitamin B-12 deficiency at Kaiser hospitals in Northern California between January 1997 and June 2011.

They compared those records with those of about 184,200 patients without the deficiency and found B-12 deficiency significantly more common in patients who took the acid-suppressing medications for at least two years. Twelve percent of the patients who took the drugs were vitamin-deficient, compared with 7.2 percent of the patients who didn't.

Several manufacturers of the drugs did not respond to requests to comment or declined to comment on the study.

Talk to doctor

Dr. Keith Obstein, a gastroenterologist at Vanderbilt University Medical Center in Nashville and a committee member of the American College of Gastroenterology, said the study gives physicians another potential side effect to discuss with their patients.

Obstein said he routinely checks his patients' B-12 levels, and he said doctors generally try to limit the length and dose of the drugs. But some patients need to be on them long term.

"Without it, they have horrible symptoms that really affect their daily lives," he said. "If this medication can help them have a more manageable and a better quality of life, then it's worthwhile."