[12-15-2011] The U.S. Food and Drug Administration (FDA) is notifying the public that it has revised the dose limitation for the cholesterol-lowering drug simvastatin from 10 mg to 20 mg when it is co-administered with the cardiac drug amiodarone. In June 2011, FDA previously recommended that the dose limitation for simvastatin be decreased from 20 mg to 10 mg, and has now reconsidered that recommendation.
In patients who are taking both simvastatin and amiodarone, the dose of simvastatin should not exceed 20 mg per day. The simvastatin drug labels (Zocor and generics, Vytorin) have been updated to reflect this correction.
In June 2011, FDA restricted the use of the highest approved dose of simvastatin (80 mg) to reduce the risk of muscle injury (myopathy). Therefore the 40-mg dose became the maximum safe dose of simvastatin. At the same time, FDA also proportionally lowered (i.e., a 50% reduction or more) all the maximum safe doses of simvastatin when it is taken with certain interacting drugs (i.e., drugs that can raise simvastatin blood levels). However, the simvastatin dose limitation when taken with amiodarone (in which the simvastatin dose was lowered from 20 mg to 10 mg) was made in error. Unlike other interacting drugs, there were no pharmacokinetic or clinical trial data to support the simvastatin dose reduction approved with amiodarone. Therefore FDA has determined that the simvastatin dose limitation, when taken with amiodarone, should be restored to 20 mg.
For a detailed discussion of the data that FDA evaluated, refer to the FDA Review (PDF - 5MB) (on page 33 of 216).
Healthcare professionals and patients can access the latest drug label for simvastatin here.
FDA Drug Safety Communication: New restrictions, contraindications, and dose limitations for Zocor (simvastatin) to reduce the risk of muscle injury[ARCHIVED]
FDA Drug Safety Podcast for Healthcare Professionals: Revised dose limitation for Zocor (simvastatin) when taken with amiodarone[ARCHIVED]