The benefits of statins substantially outweigh their risks for most people. But the drugs are not risk-free. Up to 15 percent of patients develop muscle aches, soreness, tenderness, or weakness. These are generally minor, but for some people they can be so painful that the person has to stop taking the drug. Higher doses tend to cause more problems.

Related to this effect on muscles, a very tiny fraction of people who take statins suffer a life-threatening form of muscle breakdown called rhabdomyolysis. This can cause permanent kidney damage and coma. Again, higher doses raise the risk.

Liver damage is also a rare complication of taking statins. That's why your doctor should order a liver function test before you start taking one, and periodically while you're on it. Watch for trouble signs like muscle weakness or pain, feeling very tired, nausea and vomiting, stomach pain, brown or dark colored urine, or yellowing skin. Stopping the drug usually ends the problem.

Finally, you should be aware that while most doctors embrace statins, some experts worry that the drugs are prescribed too often and that their benefits have been oversold.

We think the evidence is clear that people with established heart disease or multiple risk factors for heart disease do benefit from statins. What's still evolving and needs further study is whether statins can also lower risk in people whose LDL is only marginally high and who have no or perhaps only one heart disease risk factor. For now, we advise such people to start by eating right, exercising more, losing weight, and quitting smoking. They should turn to statins only if making those changes just doesn't do enough.