FDA Restricts Use of Simvastatin 80 mg

Michael O'Riordan

 The Food and Drug Administration is recommending that physicians restrict prescribing high-dose simvastatin (Zocor, Merck) to patients, given an increased risk of muscle damage [1]. The new FDA drug safety communication, issued today, states that physicians should limit using the 80-mg dose unless the patient has already been taking the drug for 12 months and there is no evidence of myopathy.
"Simvastatin 80 mg should not be started in new patients, including patients already taking lower doses of the drug," the agency states.
In addition, the FDA is requesting that additional changes be made to the drug's label. The label will be changed to include the new dosing recommendations, as well as warnings not to use the drug with various medications, including itraconazole (Sporanox, Jannsen Pharmaceutica), ketoconazole (Nizoral by Ortho-McNeil Pharmaceutical), posaconazole (Noxafil, Merck), erythromycin, clarithromycin, telithromycin (Ketek, Sanofi-Aventis), HIV protease inhibitors, nefazodone, gemfibrozil, cyclosporine, and danazol.
In addition, the 10-mg dose should not be exceeded in patients taking amiodarone, verapamil, and diltiazem, and the 20-mg dose should not be exceeded with amlodipine (Norvasc, Pfizer) and ranolazine (Ranexa, Gilead).
The changes to the label are based on the Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH), a study reported by heartwire . In that trial, 52 patients taking the 80-mg dose developed myopathy compared with one patient treated with the 20-mg dose. In addition, 22 patients treated with the high dose of simvastatin developed rhabdomyolysis compared with none treated with the 20-mg dose.
The FDA notes that the risks of myopathy and rhabdomyolysis were highest in the first year and that older age and female sex increased the risks.
In statement released today following the FDA alert [2], Merck notes that it has launched a new information website and is encouraging patients who think the prescribing changes might affect them to speak with their doctors.
Dr Steven Nissen (Cleveland Clinic, OH), who wrote an editorial accompanying the 2004 publication of the A to Z trial, a study that tested high-dose simvastatin in acute coronary syndrome patients, who was critical of the high rate of myopathy in that study, called the FDA decision "appropriate" but said it comes late.
"Most knowledgeable lipid experts stopped administering the 80-mg dosage of simvastatin years ago," he said in an email to heartwire . "Unfortunately, once again the FDA has been too slow to react to a serious drug safety problem. We currently have more than two million Americans taking an unsafe dosage of simvastatin when there are safer alternatives. I'm glad the FDA acted but wish they hadn't taken so long."

References

1. Food and Drug Administration. FDA drug safety communication: New restrictions, contraindications, and dose limitations for Zocor (simvastatin) to reduce the risk of muscle injury. June 8, 2011. Available here.
2. Merck. US prescribing information for simvastatin revised to include new limits on the use of the highest dose--80 mg--and updated drug interaction information [press release]. June 8, 2011. Available here.