COMMENTARY

Clarifying Simvastatin Warnings -- It's Not Just 80 mg

Sandra A. Fryhofer, MD

Disclosures

September 28, 2011

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Hello. I'm Dr. Sandra Fryhofer. Welcome to Medicine Matters. The topic is the simvastatin saga, our review of the FDA's latest warnings about this popular statin. Here's why it matters.

When my patients needed statins, I always started with simvastatin. It was generic. It was on all the pharmacy plans. The price point was right. Prescribing was hassle free. There were no complex forms to fill out and explain to my patients. But on June 8, 2011, the FDA released new warnings about the dangers of high-dose simvastatin, which affects many people. In 2010, an estimated 2.1 million US patients were prescribed a product containing 80 mg simvastatin. The FDA also issued new warnings about dosing and drug interactions. Here are the highlights:

Restrictions for 80-mg simvastatin

  • Avoid prescribing 80-mg simvastatin because of the high risk for myopathy.

  • 80-mg simvastatin is satisfactory if the patient has been on it for a year with no evidence of myopathy.

Restrictions for intermediate- and low-dose simvastatin

  • No more than 20 mg for patients taking amlodipine and ranolazine

  • No more than 10 mg for patients on amiodarone, verapamil, and diltiazem

Restrictions for simvastatin at any dose

  • The FDA has mandated drug-labeling changes warning that simvastatin is contraindicated in patients on gemfibrozil, certain antifungal medications (itraconazole, ketoconazole, posaconazole), certain antibiotics (erythromycin, clarithromycin, telithromycin) as well as HIV protease inhibitors, nefazodone, cyclosporine, and danazol.

The information on adverse effects with simvastatin are not new. In 2004, when the A to Z trial was published in JAMA,[1] an editorial expressed concerns about increased rates of myopathy in patients on simvastatin. The most recent study to cast aspersions on simvastatin was SEARCH, published in The Lancet in 2010.[2] It linked simvastatin 80-mg doses to increased risk for myopathy.

So why didn't the FDA act sooner? That's not clear, but the word is out now. Simvastatin problems are public property. Patients know about them and depend on us to clear up their medication regimens. Not all statins are created equal and the least expensive drug may not necessarily be the best for your patient. Please also check "Switching From Simvastatin 80 mg: How to Shop for Statins" from my column Staying Well. For Medicine Matters, I'm Dr. Sandra Fryhofer.

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