FDA: Zocor Risk to Muscles

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Based on new data, the FDA warned that higher doses of the cholesterol-lowering drug Zocor, sold generically as simvastatin, carry an increased risk of muscle injury.

The FDA also warns that mixing Zocor with certain other drugs also increases patients' risk of muscle injury, including the rare but serious complication known as rhabdomyolysis. Rhabdomyolysis can sometimes result in fatal kidney damage.

From the FDA site:

Based on review of data from a large clinical trial and data from other sources, the U.S. Food and Drug Administration (FDA) is informing the public about an increased risk of muscle injury in patients taking the highest approved dose of the cholesterol-lowering medication, Zocor (simvastatin) 80 mg, compared to patients taking lower doses of simvastatin and possibly other drugs in the "statin" class.

The clinical trial data being reviewed is from the Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH) trial. The agency is also reviewing data from other clinical trials, observational studies, adverse event reports, and data on prescription use of simvastatin to better understand the relationship between high-dose simvastatin use and muscle injury


Patients should:

* Not stop taking simvastatin unless told to by their healthcare professional.
* Talk to their healthcare professional about any questions they have about the use of simvastatin.
* Call their healthcare professional if they experience any of the following: muscle pain, tenderness or weakness, urine that is dark or red-colored, or unexplained tiredness.


Rhabdomyolysis (often shortened to simply "rhabdo") is the rapid breakdown (lysis) of skeletal muscle (rhabdomyo) due to injury to muscle tissue. The muscle damage may be caused by physical (e.g., crush injury), chemical, or biological factors. The destruction of the muscle leads to the release of the breakdown products of damaged muscle cells into the bloodstream; some of these, such as myoglobin (a protein), are harmful to the kidney and may lead to acute kidney failure.

The damage is more common at the highest approved dose of Zocor, 80 mg. A large clinical trial comparing 6,031 patients taking 80 mg. daily with 6,033 patients taking 20 mg. found 52 cases of myopathy in the 80-mg. group and only one in the 20-mg. group. Eleven patients in the 80-mg. group developed rhabdomyolysis, but none in the low-dose group.