Amiodarone significantly increases simvastatin blood levels, raising the risk of severe muscle damage (rhabdomyolysis) and kidney failure. The FDA has set a maximum simvastatin dose of 20 mg daily for patients taking amiodarone to reduce this risk.
How This Interaction Works (Mechanism)
Amiodarone is a potent inhibitor of CYP3A4, the primary enzyme responsible for simvastatin metabolism. This inhibition can increase simvastatin plasma levels by 100 to 200 percent, dramatically raising the risk of myopathy and rhabdomyolysis. Simvastatin's active metabolite (simvastatin acid) is particularly susceptible to CYP3A4 inhibition. Rhabdomyolysis involves the breakdown of skeletal muscle fibers, releasing myoglobin into the bloodstream, which can cause acute kidney failure.
Source: FDA Drug Safety Communication on Simvastatin Dose Limitations, 2011 (reaffirmed 2024)
Do not exceed 20 mg of simvastatin daily when taking amiodarone. Better yet, switch to a statin that is not metabolized by CYP3A4, such as pravastatin or rosuvastatin, which are not affected by amiodarone. Report any unexplained muscle pain, tenderness, weakness, or dark urine immediately. Regular creatine kinase (CK) monitoring may be warranted.
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Simvastatin and Amiodarone have a severe interaction and should generally not be taken together without close medical supervision. The combination can cause serious, potentially life-threatening side effects. Contact your doctor immediately if you are currently taking both medications.
Amiodarone significantly increases simvastatin blood levels, raising the risk of severe muscle damage (rhabdomyolysis) and kidney failure. The FDA has set a maximum simvastatin dose of 20 mg daily for patients taking amiodarone to reduce this risk.
Yes. Anytime you are taking multiple medications, supplements, or substances, you should inform your doctor and pharmacist. They can evaluate your specific risk factors (age, kidney function, other medications, medical conditions) and determine whether the Simvastatin and Amiodarone combination is safe for you, or whether adjustments are needed.
Related Resources
- Supplement interactions with Simvastatin on Health Britannica
- Supplement interactions with Amiodarone on Health Britannica
- Simvastatin prices and pharmacy comparison on RxGrab
- Amiodarone prices and pharmacy comparison on RxGrab
- Full drug interaction checker tool
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