FDA Limits Highest Dose of Zocor

June 9, 2011 -- The FDA today tightened its rules on who should take the highest approved dose of the statin drug simvastatin.

Simvastatin, which lowers LDL "bad" cholesterol, is sold under the brand name Zocor and as a generic drug. It's also an active ingredient in the drugs Vytorin and Simcor.

Due to the possible risk of muscle injury, the FDA now recommends that no new patients should start taking that dose -- 80 milligrams.

The highest dose of simvastatin is not off limits for everyone. But it's only for patients who have taken the 80-milligram dose for at least 12 months with no signs of muscle injury. That's because the muscle risk appears highest during the first 12 months on the drug.

"Patients who are unable to adequately lower their level of [LDL cholesterol] on simvastatin 40 mg should not be given the higher 80 mg dose of simvastatin," the FDA says in a news release. The FDA says doctors should give those patients another treatment to lower their LDL cholesterol.

The FDA began reviewing high-dose simvastatin and risk of muscle injury in March 2010. Today's recommendation is the result of that review.

"We encourage those who think these changes might affect them to talk to their doctor. Patients should talk with their doctor before they stop taking any of their medicines," Michael Rosenblatt, MD, chief medical officer for Merck, the drug company that makes simvastatin, says in a news release.