Statin side effects: How common are memory loss, diabetes, and muscle aches?

By Deborah Kotz, Globe Staff

When the US Food and Drug Administration told the makers of cholesterol-lowering statins to add new side effect warnings to their labels last week, many of the 40 million statin users may have been unaware of the extent of the risks associated with these drugs that have been touted by some cardiologists to be safer than aspirin.

No question, statins -- which include Lipitor (atorvastatin), Zocor (simvastatin), and Crestor (rosuvastatin) -- are relatively safe drugs, and theyve saved thousands of lives over the past 20 years, particularly in men with established heart disease. But like any drug they can cause problems in some, including muscle aches, an increased risk of diabetes, and, gaining recent attention, memory loss.

University of California-San Diego researcher Beatrice Golomb published a paper two years ago describing 171 statin users who reported that they had developed memory problems and dementia-like symptoms that they attributed to their use of the medications. The vast majority experienced an improvement in their symptoms after stopping the drugs and many saw their symptoms return after going back on statins.

Robert Grindell, a state employee from Makinen, Minn., told me his short-term memory began to deteriorate after he started taking Zocor in his early 50s. My co-workers told me I was coming in to ask them the same question three times in one day, he said. I had a CT scan to determine if I had a stroke, but it came back fine; the next day, I couldnt even remember where I had the test performed. After learning that Zocor caused memory problems, Grindell decided to go off it and said within a few days he noticed an improvement in his memory, not having to glance down several times at a printed phone number as he dialed it to remember the digits.

Unfortunately, the exact incidence of these memory problems isnt known. Manufacturer-sponsored clinical trials show that they occur in fewer than 1 percent of users, but statin researcher Dr. Paul Thompson, chief of cardiololgy at Hartford Hospital, said the real incidence is probably much higher. He has a study expected to be published sometime this year that measured cognitive effects in statin users compared with those on placebos that he said will provide a better estimate.

The diabetes risks of statins are more well-established. One review study published last year calculated an extra two cases of diabetes in every 1,000 patients who took a high-dose statin (80 milligrams) compared with those who took a lower dose (20 to 40 milligrams). And one clinical trial found that statin users had about a 25 percent increased risk of developing diabetes over a two-year period compared with those who took placebos.

Experts, though, agree that in people at high risk for heart disease, the increased diabetes risk is outweighed by the statins protection against heart attacks and deaths from any cause.

The danger of muscle destruction from statins -- which can damage the liver and kidneys -- is also clear but slight. In its label change, the FDA decided to stop recommending routine liver enzyme tests in statin users since the occurence of serious problems is rare. According to Thompson, about 1 in every 1,000 statin users will develop severely elevated liver enzymes that indicate muscle death called rhabdomyolysis, and only 1 in 10 million die from developing an extremely severe case.

Muscle aches are far more common: occuring in about 1 in 10 users, according to Thompson. It seems to be more common in people who do a lot of exercise. In fact, a study he conducted found that marathon runners taking statins developed a greater increase in the liver enzyme creatine kinase right after their race compared with runners who werent on statins.

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Statin side effects: How common are memory loss, diabetes, and muscle aches?