MUSCLE-RELATED EFFECTS OF ANTI-CHOLESTEROL DRUGS WARRANT ATTENTION

People with neuromuscular disorders need not be more concerned than the average person about muscle-related side effects of cholesterol-lowering drugs, but they should be aware of these effects, neurologist Lawrence Z. Stern says. Stern is MDA's Medical Consultant and directs MDA's Mucio F. Delgado Clinic for Neuromuscular Disorders at the University of Arizona Health Sciences Center in Tucson.

On Aug. 8, the Bayer Corp. of Pittsburgh voluntarily pulled from the market its cholesterol-lowering drug Baycol (cerivastatin), which was initially approved in the United States in 1997 (www.bayerpharma-na.com). The drug was removed from the market, with the support of the U.S. Food and Drug Administration (www.fda.gov/medwatch/; search for Baycol), because its use was significantly associated with a type of acute, severe muscle destruction known as rhabdomyolysis.

Rhabdomyolysis, which not only destroys muscles but can lead to death as a result of the effects on kidneys and circulation of muscle breakdown, has been associated with cholesterol-lowering drugs that belong to a class known as statins. However, Baycol has shown a greater association with this problem than have other statin compounds.

There have been 31 reported deaths with Baycol, 12 of which involved simultaneous use of another medication, gemfibrozil (Lopid), which lowers lipids in the blood. High doses of Baycol and its use in elderly people have also been noted as risk factors for muscle damage.

Signs and symptoms of rhabdomyolysis include muscle pain and cramps, weakness, malaise, fever, nausea, vomiting, cola-colored urine and elevated levels of the enzyme creatine kinase (CK) in the blood. Unfortunately, Stern says, many of these signs and symptoms overlap with those of muscle disorders, especially some of the metabolic diseases and inflammatory diseases of muscle.

For someone who's taking a statin drug to lower cholesterol and who also has a muscle disease, the onset of statin-associated rhabdomyolysis can be hard to detect. The overlapping symptoms can also make it difficult for a physician to interpret changing lab values, such as CK levels, in someone with a muscle disease who's taking statins.

However, Stern doesn't advise anyone to stop taking a prescribed statin medication, such as lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), fluvastatin (Lescol) or atorvastatin (Lipitor).

"People with high cholesterol should exercise more and control their diets to lower their cholesterol levels, but not everyone has the time, determination or ability to do that," he says. "So, for many people, these drugs are necessary to help avoid life-threatening cardiovascular conditions."

Stern advises neuromuscular disease patients taking statin drugs to keep in close touch with a physician who's aware of both conditions and of possible effects of statins on CK levels. These levels are often used to monitor the effects of treatment for inflammatory myopathies such as polymyositis and dermatomyositis, so disease progression and statin-related muscle destruction can easily be confused.

While it isn't known whether people with neuromuscular disorders are at increased risk for statin-associated rhabdomyolysis, Stern advises that anyone on a statin drug who notices cola-colored urine contact a physician immediately. This color in the urine can signal the presence of the protein myoglobin, a product of muscle breakdown, which can quickly damage the kidneys.

For more information about rhabdomyolysis, see www.drkoop.com/conditions/ency. Go to the R section for rhabdomyolysis.