Dear Dr. Roach:

Dear Dr. Roach:

I think I may have polymyositis. My thigh muscles (specifically, the lateral muscles) are weak and achy. I take a statin, and I don’t like what I read about them.

Statins indeed can cause muscle aches in some people who take them. In clinical trials, about 5 percent of people will develop some aches, but significant damage to the muscles occurs in less than 1 percent of people who take statins. About two-thirds of the time, symptoms begin within six weeks of starting the statin.

People with weakness should stop taking the statin and see their doctor, who will do an exam and look for evidence of muscle breakdown using a blood test.

If the blood level (especially for CPK, or creatine phosphokinase, released into the blood with muscle breakdown) is high and the problems go away when you stop taking the statin, then the diagnosis is straightforward.

Answer: — L.P.

However, some people can have muscle symptoms without an elevated CPK.

Many people can tolerate a different statin if they develop muscle aches on one: Pravastatin and fluvastatin, in particular, are metabolized differently and may not cause symptoms. It requires judgment to evaluate the severity of the symptoms and the muscle damage versus the potential benefit of taking a statin.

There are many causes of muscle aches. Some people have subtle genetic differences that predispose them to muscle problems, which never come out unless they are stressed by severe exercise or a statin.

People with low thyroid levels are more likely to develop problems from statins.

Polymyositis is an inflammatory muscle disease that may have nothing to do with statins.

It would be unusual to be so localized to only the lateral thigh, however.

My 42-year-old son has had a few calcium readings that are high, but his endocrinologist doesn’t seem to be seeing the forest for the trees.

He thinks all is fine, even though the last reading was 10.2 and previously had been