By THOMAS M. BURTON and RON WINSLOW
The Food and Drug Administration warned that patients taking cholesterol-fighting statins face a small increase in the risk of higher blood-sugar levels and of being diagnosed with diabetes, raising concerns about one of the country's most widely prescribed groups of drugs.
The federal safety agency said Tuesday it plans to require drug makers to add the diabetes-risk language to the "warnings and precautions" section of the labels on statin drugs.
Statins include top-selling brand names such as Lipitor, Crestor, Zocor and a dozen or so other branded and generic versions under various names. The drugs are prescribed to more than 20 million Americans a year, at a cost of more than $14 billion in 2011, according to the research firm IMS Health.
The warning isn't expected to prompt doctors to stop prescribing statins for patients with multiple risk factors for heart attack. Cardiologists said for many patients, the benefits of statins still outweigh these risks.
The diabetes issue is "real" but "not a huge effect," said Robert Califf, vice chancellor for clinical research and a cardiologist at Duke University Medical Center. "Informing people is a good thing, but for the vast majority of people who really need to be on a statin, this shouldn't change what they do."
But some physicians cautioned that the risk wasn't insignificant and that patients at lower risk for heart problems might want to reassess whether they should remain on statins.
"The diabetes issue is a really big deal. We're overcooking the statin use," said Eric J. Topol, a prominent cardiologist and chief academic officer of Scripps Health in LaJolla, Calif.
In addition, the FDA said labels for statin drugs now will contain information about patients experiencing memory loss and confusion, though this side effect was classified as an "adverse reaction" rather than one of the warnings and precautions, a more serious category.
Amy Egan, the FDA's deputy director for safety of metabolic and endocrinological products, said "these cognitive changes can be quite dramatic" and "sustained" but that they disappear when statin therapy is stopped. Dr. Egan said the agency cannot identify a specific drug or age group of people who might be prone to such cases. She said patients should notify their doctors if these symptoms occur.
The FDA made new labeling recommendations for one specific statin, Mevacor, generically called lovastatin. It said that some medicines like protease drugs used to treat AIDS and drugs for bacterial and fungal infections shouldn't be taken with Mevacor because of interactions that may lead to muscle injury.
At the same time, the FDA announced that drug makers could remove a label warning that liver enzymes need to be monitored during statin therapy. It cited the fact that "serious liver injury with statins is rare and unpredictable" and that periodic monitoring "does not appear to be effective in detecting or preventing this rare side effect."
AstraZeneca PLC, which makes Crestor, the only major statin still sold exclusively as a brand-name drug, said in a statement that "the cognitive issues are generally nonserious and reversible upon discontinuation" of a statin. It said reports about increased blood sugar were already included on Crestor labels.
In addition to the pure statins, products that contain statins include Advicor, Simcor and Vytorin. Merck & Co., which makes Zocor and Vytorin, said information for those drugs was "updated" in October in a way that reflects the contents of the FDA's Tuesday safety advisory. It revised labeling for Mevacor more recently.
The FDA's action follows analyses of large numbers of statin studies in recent years. In one, published in the Lancet in 2010, researchers looked at 13 studies including 91,140 patients. The researchers concluded that statin therapy "is associated with a slightly increased risk of development of [Type 2] diabetes, but the risk is low both in absolute terms and when compared to the reduction in coronary events."
Cardiologists differed on how to weigh the findings, especially for the millions of people given the drugs for the prevention of a first heart attack or stroke.
Steven E. Nissen, chairman of cardiovascular medicine at the Cleveland Clinic, said, "There is no question that statins slightly increase the risk of a diabetes diagnosis and of slightly higher blood sugar, but I think this has no impact on the risk-benefit assessment. I know I can lower the [relative] risk of death, stroke and heart attack by about 30%" in patients at high risk of such cardiovascular events.
Dr. Topol said research suggests that for every 200 people who take a statin, 1 will develop diabetes. By comparison, 1 to 2 out of 100 patients at risk for a heart attack will avoid one, he said, adding, "That's a very narrow margin of benefit," he said.
Rita Redberg, a cardiologist at the University of California, San Francisco Medical Center, stressed the long-term concerns about diabetes. "We know that diabetes is a significant risk factor for heart disease," Dr. Redberg said. She said the statin-diabetes link "raises the concern that over time the diabetes risk will outweigh the cholesterol-lowering benefit on overall risk of cardiovascular disease."