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

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 they’ve 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 the statin users 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.

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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. (He contacted Golomb after hearing about her research.) “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 couldn’t 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 isn’t 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 findings can’t be disclosed until the study is published.

The diabetes risks of statins are more well-established. One review study published last year calculated an extra two cases of type 2 diabetes in every 1,000 patients who took a high-dose statin (80 milligrams per day) 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 statin’s 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. According to Thompson, about 1 in every 1,000 statin users will develop severely elevated levels of the enzyme creatine kinase, which indicates muscle death, and only 1 in 10 million die from developing an extremely severe case of the condition called rhabdomyolysis.

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 creatine kinase right after their race compared with runners who weren’t on statins.

“We also see more muscle aches in older people and women since they have less muscle mass,” he said. Lowering the statin dose or switching to a different statin doesn’t always help, Thompson said. “In our studies, those who develop statin myalgia tend to get it again and again; they’re body may get sensitized to statins.” There may also be a genetic component, with statin muscle aches occuring more often in those whose parents also had them.

And there may be a link between memory loss and muscle aches. “In our database, the majority of patients who had cognitive problems also had muscle problems,” Golomb said. She recommends that those who are having memory loss or muscle aches speak to their doctor about going off statins—especially if they’re not in a high-risk group for heart attacks.

Those who get the most benefits are men under 65 who’ve already had a heart attack, she said. Women, elderly people, and those without heart disease get much smaller benefits from statins, and it’s unclear whether the drugs extend their lives.

“Many patients have told me that their doctor said going off statins would kill them,” Golomb said, “but that’s not an accurate representation of the evidence.”

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