U.S. Prescribing Information for Simvastatin Revised

The changes follow a U.S. Food and Drug Administration (FDA) review, announced by the agency in March 2010, of the risk of muscle injury (called myopathy, including its most serious form, rhabdomyolysis) with the highest dose of simvastatin. Merck has updated the U.S. prescribing information:

• To limit the use of the high dose of simvastatin, 80 mg, which is taken by approximately 12 percent of U.S. simvastatin users, to patients who have been taking that prescribed amount chronically (e.g., for 12 months or more) without evidence of muscle toxicity; and, in addition,
• To contraindicate and/or limit the dose of simvastatin when used with certain drugs where the combined use may increase the risk of myopathy and rhabdomyolysis.

In addition to limiting use of the 80 mg dose, the updated U.S. prescribing information modifies limitations on concomitant use of simvastatin with certain drugs:

• the use of simvastatin is contraindicated with certain azole antifungals and antibiotics, with HIV protease inhibitors, and with the drugs nefazodone, gemfibrozil, cyclosporine, and danazol; and
• the maximum recommended doses of simvastatin have been revised when used with amiodarone, ranolazine, and the calcium channel blockers verapamil, diltiazem and amlodipine.