The FDA is putting the brakes on high doses of the Merck statin drug simvastatin, sold under the brand name Zocor and in generic versions. The drug has been linked with a risk of muscle injury, particularly at high doses. So, the agency recommends new patients use lower doses--20 mg and 40 mg--rather than the 80 mg version, until they've taken the drug for at least a year without harm to their muscles.
The changes come after an FDA review of a seven-year study of adverse event reports, plus other research indicating that the higher dose put patients at greater risk of muscle pain and weakness called myopathy. More serious cases, known as rhabdomyolysis, can cause kidney damage, the Wall Street Journal notes.
FDA also recommended lower doses for simvastatin when used with a list of other drugs, including some antibiotics, some HIV fighters, and some heart medicines. The restrictions could apply to combination drugs that include simvastatin: Vytorin, a Merck brand that also contains the cholesterol-fighter Zetia; and Simcor, a simvastatin-and-niacin combo sold by Abbott Laboratories.
Merck points out that only 12 percent of simvastatin users take the 80 mg dose. Still, about 2.1 million patients were prescribed a product that contained 80 mg of simvastatin last year, FDA says. Along with the 20 mg and 40 mg doses, in 2010 simvastatin was the second-most prescribed drug in the U.S., Reuters notes.