Labeling updates and warnings through September 2008

Labeling updates and warnings through September 2008 for intramuscular naltrexone (Vivitrol) and for simvastatin (Zocor; generic simvastatin), ezetimibe/simvastatin (Vytorin), and niacin extended-release/simvastatin (Simcor) when used concurrently with amiodarone (Cordarone; Pacerone; generic amiodarone)

FDA has issued an alert to healthcare professionals noting that there is a risk of rhabdomyolysis, which can lead to kidney failure or death, when patients are treated concurrently with simvastatin and amiodarone. This risk increases when a simvastatin dose >20 mg/d is administered concurrently with amiodarone. Although the labeling for simvastatin was revised in 2002 to include this potential risk, FDA has continued to receive reports of rhabdomyolysis in patients treated with amiodarone and simvastatin. Healthcare professionals should avoid prescribing simvastatin doses >20 mg/d in patients who are taking amiodarone. This alert applies to simvastatin (Zocor, Merck; generic simvastatin), ezetimibe/simvastatin (Vytorin, Merck/Schering-Plough), and niacin extended-release/simvastatin (Simcor, Abbott) when used concurrently with amiodarone (Cordarone, Wyeth; Pacerone, Upsher-Smith; generic amiodarone).

FDA has issued an alert regarding the risk of adverse injection-site reactions in patients administered intramuscular naltrexone (Vivitrol, Alkermes/Cephalon) for the treatment of alcohol dependence. FDA has received reports of cellulitis, induration, hematoma, abscess, sterile abscess, and necrosis in patients who were treated with naltrexone; some of these cases required surgical intervention. Healthcare professionals should instruct patients to monitor the injection site for pain, swelling, tenderness, induration, bruising, pruritus, or redness that does not improve or worsens within 2 weeks after the injection.