Addendum January 5, 2012
In December 2011, the FDA revised the dose limitation for simvastatin (Zocor) from 10 mg to 20 mg when it is co-administered with 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.
You'll finally see stronger dosing limits for simvastatin...Zocor, Vytorin, etc.
Some experts have been calling for an end to high-dose simvastatin since 2004 because of myopathy concerns.
But there's still over 2 million people taking the 80 mg dose...it's the most potent option before going to a brand-name statin.
Recommend following the latest restrictions.
Don't exceed 40 mg of simvastatin...unless patients have been on the 80 mg dose for a year without myopathy.
Explain that increasing the dose from 40 to 80 mg/day only lowers LDL an extra 6%...but increases myopathy risk by 7 times or more.
If simvastatin 40 mg isn't enough, suggest going to atorvastatin (Lipitor) 40 mg or rosuvastatin (Crestor) 10 to 20 mg. A generic for Lipitor will be out later this year.
Don't exceed 20 mg with amlodipine or ranolazine.
Don't exceed 10 mg with amiodarone, verapamil, or diltiazem.
Don't use simvastatin at all with gemfibrozil or strong CYP3A4 inhibitors...itraconazole, clarithromycin, protease inhibitors, etc.
Also be careful about combining simvastatin with other fibrates, niacin 1 g/day or more, or dronedarone (Multaq).
See our PL Charts, Clinically Significant Statin Drug Interactions, to check for interactions and alternatives...and Statin Dose Comparisons if you need to switch between statins.
www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsand
Providers/ucm204882.htm (6-16-11). JAMA 2004;292:1365.