Citing Muscle Risks, FDA Restricts Highest Zocor DoseJun 9, 2011 | Parker Waichman LLP
Patients taking the statin Zocor (simvastatin) should not be given the highest 80 mg dose in their first year of treatment, according to the U.S. Food & Drug Administration (FDA). The agency's review of a clinical trial, as well as an analysis of its adverse even reports prove that such patients face the highest risk of suffering myopathy (severe muscle injury), including it's most severe form, rhabdomyolysis.
Zocor 80 mg should be used only in patients who have been taking this dose for 12 months or more without evidence of muscle injury, the FDA said. The FDA also said health care professionals should switch such patients to another statin if they find that taking 40 mg of simvastatin isn't meeting their LDL cholesterol goal, rather than raising the simvastatin dose to 80 mg.
The agency also revised the labels for generic forms of simvastatin, Vytorin and Simcor. In addition, the FDA has revised the labeling of simvastatin products to include new dosing recommendations when these drugs are used with certain medications that interact to increase the level of simvastatin in the body, which can increase the risk for myopathy.
Muscle injury is a known side effect of statins, and drugs in this class already bear a warning to this effect. But evidence reviewed by the FDA indicates the risk is higher among patients treated with high dose Zocor during their first 12 months of therapy. That evidence included Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH) revealed 52 cases of myopathy occurring in the group of patients treated with 80 mg simvastatin versus one in the group treated with 20 mg. Twenty-two patients in the 80-mg group developed rhabdomyolysis, while none in the 20-mg group developed the disorder.
The risks for myopathy and rhabdomyolysis with the 80 mg dose were highest in the first 12 months of treatment, 5 per 1000 person-years and 2 per 1000 person-years, respectively. The risk for myopathy decreased to 1 per 1000 person-years after one year, while the risk for rhabdomyolysis fell to 0.4 per 1000 person-years, the agency said.
According to a report in The New York Times, the FDA's decision to restrict high-dose Zocor is viewed by many as long-overdue.
“Most experts in the field have known for many years that these high doses of Zocor were not safe compared with the other statins," said Dr. Steven E. Nissen, chairman of cardiovascular medicine at the Cleveland Clinic.
Nissen pointed out that two other statins - Lipitor and Crestor - are more potent and can accomplish the same cholesterol targets at lower doses, the Times said.