Harvard Heart Letter

4 myths about statins



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Some side effects attributed to taking a statin may be caused by a different problem.

Don't let misconceptions about these medications prevent you from taking them.

More than one in four adults ages 45 and older in the United States take a cholesterol-lowering statin. But these popular medications are often misunderstood. Here's what you need to know to take them safely.

MYTH 1 Statins cause memory loss.

Some people who take statins report confusion or memory loss. But because memory issues tend to crop up in middle-aged and older adults (the most common users of statins), it's hard to tell if the drug, or another problem such as age-related memory loss, might be to blame.

The initial concern arose from a number of self-reported complaints to the FDA, says cardiologist Dr. Christopher Cannon, a Harvard Medical School professor. "However, many of the reports were from people who took the drug for just one day," he says, which suggests that the statin wasn't to blame. More reliable data come from large studies—one of which included more than 20,000 people—that revealed no effect on thinking and memory caused by statins.

MYTH 2 You need regular blood tests to check your liver and kidney function.

Because statins target liver cells, early statin users were advised to get routine blood tests to check their liver enzyme levels, since rising levels warn of possible liver damage. Other tests measured creatine kinase (CK), a byproduct of muscle breakdown that can signal the early stages of rhabdomyolysis. This condition, which occurs in about one in 10,000 statin users, can lead to kidney failure and even death.

But neither of these routine tests proved to accurately predict these serious but very rare problems. In 2012, the FDA changed the recommendations to a single test of liver enzymes and CK when a person starts taking a statin, switches to a new one, or develops symptoms of liver or muscle injury. Symptoms of liver injury include unusual fatigue, loss of appetite, upper abdominal discomfort, dark-colored urine, or yellowing of the skin or whites of the eyes.

About one in 10 people reports muscle pain and weakness after starting a statin. Like memory lapses, muscle aches are fairly common in middle age and beyond and may result from vigorous exercise, yard work, or even just a long session hunched over the computer. But in the absence of such an explanation, you might suspect the statin, especially if the muscle pain began within a few weeks of starting the statin and affects both sides of your body. Your doctor may recommend a lower dose or a different statin, which often resolves the problem.

MYTH 3 Taking CoQ10 prevents muscle aches caused by statins.

Coenzyme Q10 (CoQ10) is a vitamin-like substance made naturally by the body that is involved in energy production in all your cells. It's also sold as a dietary supplement and touted as a way to boost energy and "support heart function," as the product labels assert. Taking a statin lowers CoQ10 levels, and scientists have wondered if raising blood levels of CoQ10 might help treat statin-related muscle aches. But so far, the results have been mixed, with no solid evidence to support that idea.

Some physicians maintain that trying the supplements for a month or so is likely safe. However, research suggests that CoQ10 may reduce the effectiveness of warfarin (Coumadin). That could raise the risk of a dangerous blood clot, so don't try CoQ10 if you are taking that medication.

MYTH 4 You can't eat grapefruit if you take a statin.

Grapefruit does contain compounds that alter how your body processes statins. The compounds, called furanocoumarins, block an enzyme in the intestine that normally breaks down statins (and many other drugs). As a result, more statin gets into the bloodstream, making it more powerful. Not all statins are affected equally, so grapefruit fans might want to switch to a statin that's less affected.

The grapefruit effect

Grapefruit juice affects certain statins more than others.

BIG EFFECT

LITTLE or NO EFFECT

atorvastatin (Lipitor)

lovastatin (Mevacor)

simvastatin (Zocor)

fluvastatin (Lescol)

pitavastatin (Livalo)

pravastatin (Pravachol)

rosuvastatin (Crestor)

But if you can't switch, a small glass of the juice is probably fine, says Dr. Jorge Plutzky, an associate professor of medicine at Harvard Medical School and medical editor of Managing Your Cholesterol, www.health.harvard.edu/MC.

"The studies showing dangerous effects included very high amounts of furanocoumarins, found in a quart or more of the juice," he says. Since it takes several fruits to make a glass of juice, eating half a grapefruit lowers any risk even further. But to be on the safe side, check with your doctor, and avoid taking your pills with grapefruit juice.