Despite concerns about popular cholesterol-lowering "statin" (search) drugs, a new study shows that most of these drugs have a low risk of a serious muscle disorder.

The study was released early in response to controversial statements from an FDA scientist last week. That scientist, David J. Graham, MD, MPH, is also the lead researcher of the new study.

Last Thursday, Graham spoke to Congress about drug safety and the problems with the arthritis drug Vioxx, which was removed from the shelves in October due to concerns it increases the risk of heart attacks and strokes. At that hearing, he also implicated five other drugs as having safety concerns.

One of those drugs was the cholesterol-lowering drug Crestor, a member of the class of drugs called statins. Graham tells WebMD that the new study was started before Crestor became available in August 2003 and, therefore, he did not look at that statin drug.

Graham's study looked at the risk of a potentially serious muscle disorder called rhabdomyolysis among patients taking a statin drug — either Baycol, Lipitor, Pravachol, or Zocor. Baycol was removed from the market in 2001 in the wake of reports that it had led to rhabdomyolysis (search) and death in 31 people.

Rhabdomyolysis occurs when muscle tissue breaks down, releasing high levels of chemicals in the bloodstream that can cause kidney failure.

Statin Drug Risk "Similar and Low"

Graham's study included data based on more than 252,000 people treated with a statin drug or another cholesterol-lowering drug.

Graham found that nearly one out of every 23,000 people taking a statin drug alone developed rhabdomyolysis. The risk jumped tenfold in people taking Baycol, supporting the theory that this statin drug carried a much larger risk.

The researchers found that when a statin drug was combined with other cholesterol-lowering drugs called fibrates, such as Lopid and Tricor, about 60 of every 100,000 people developed rhabdomyolysis.

Graham says the risk of the muscle problem was "similar and low" for the statin drugs Lipitor, Pravachol, and Zocor. The study will appear in the Dec. 1 issue of The Journal of the American Medical Association.

However, Graham says the risk may be significantly higher in older patients with diabetes, where roughly one in 500 patients per year could develop muscle injury.

What About Crestor?

In June, the FDA advised doctors to be careful about how they prescribe Crestor.

The advisory followed label changes in Europe reflecting cautions for patients older than 65, those with underactive thyroids, and people with kidney problems, especially at the drug's highest dose, 40 milligrams. Those risks were already included on U.S. labels, according to news reports at the time.

Crestor's maker, AstraZeneca, released a statement in response to Graham's congressional hearing comments saying it is "fully confident in the safety profile of Crestor, which has now been approved in more than 65 countries worldwide.

"To date, the FDA has not given the company any indication of a major concern regarding Crestor, and the comments today are inconsistent with past public statements from the FDA and our understanding of its current view of the safety and efficacy of Crestor."

What Should Patients Do?

If patients develop muscle soreness, they should stop their medicine and call their doctor to be checked out for muscle injury, Graham tells WebMD. He says the typical patient in his study developed muscle soreness and pain about five to six days before being hospitalized with muscle injury.

Dark urine is another sign of possible muscle injury that should alert patients to call their doctor.

By Miranda Hitti, reviewed by Michael W. Smith, MD

SOURCES: Graham, D. The Journal of the American Medical Association, Dec. 1, 2004; vol 292: pp 2585-2590. WebMD Medical News: "Cholesterol-Lowering Drug Pulled Off the Market." WebMD Medical Reference provided in collaboration with The Cleveland Clinic: "Heart Disease: Lower Cholesterol to Reduce Risk." News release, AstraZeneca.