FDA adds warning about muscle injury to Zocor

WASHINGTON (AP) — The Food and Drug Administration has added new warnings to the blockbuster cholesterol Zocor, cautioning doctors that the highest dose of the drug can cause muscle damage and potentially lethal kidney damage in rare cases.

Regulators said Wednesday that patients taking the 80 milligram dose of Zocor, a statin drug, have a higher risk of muscle damage than patients taking lower doses of the drug or similar medications. The warning also applies to generic versions of the drug.

The 80 milligram dose should be continued only in patients who have been taking it for more than a year without signs of injury. New patients should start on a lower dose, the agency said in an online statement.

More than 2.1 million patients in the U.S. received a prescription for the Merck drug or a generic equivalent last year, according to the FDA. Whitehouse Station, N.J.-based Merck & Co. said about 12 percent of patients currently take the highest dose of Zocor.

“This is an important medicine for these patients because they are at the highest risk for heart disease,” said Dr. Michael Rosenblatt, chief medical officer for Merck. “Patients shouldn’t stop taking this medicine on their own. They should talk to their doctor.”

FDA-approved doses for the drug range from 5 milligrams to 80 milligrams.

The FDA said the warning is based on clinical trials, studies, reports of side effects by users and prescription data.

Patients suffering from the muscle injury, called myopathy, experience pain, tenderness and weakness and elevation of the muscle enzyme creatine kinase. The most serious form of the injury, called rhabdomyolysis, can cause fatal injury to the kidneys. The condition is rare in patients taking Zocor, affecting about 5 out of every 100,000 people taking the drug for a year.

Zocor, known chemically as simvastatin, is no longer a big seller for Merck because of cheaper generic versions. But the company reported sales of $2 billion last year for Vytorin, which combines simvastatin with another cholesterol drug, ezetimibe

Simvastatin, which is also part Abbott Laboratories’ drug Simcor, is sold by 11 generic drugmakers including Dr. Reddy’s Laboratories, Teva Pharmaceutical Industries, and Novartis’ Sandoz division.

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