Amiodarone × Atorvastatin

Amiodarone inhibits CYP3A4, which takes part in atorvastatin metabolism, so atorvastatin levels can rise (amiodarone and atorvastatin labels). No interaction studies have been done for this pair, and the size of the effect is unknown (atorvastatin label). The risk of muscle damage, up to rhabdomyolysis, rises with statin exposure (amiodarone label). Because of amiodarone's long half-life, the interaction can persist for several months after it is stopped (amiodarone label).

Muscle pain, cramps or weakness, especially with fever and malaise, and raised creatine kinase. In severe cases rhabdomyolysis develops: creatine kinase above 10 times the upper limit of normal, myoglobin in blood and urine (dark urine) and possible kidney failure (atorvastatin label).

The Spanish amiodarone label recommends using a statin that is not metabolized by CYP3A4 (amiodarone label). If atorvastatin is kept, consider a lower starting dose (FDA amiodarone label) and a lower maximum dose (atorvastatin label). Monitor the patient closely after amiodarone is started and after each dose change (atorvastatin label). Ask the patient to report muscle pain, cramps or weakness at once. If they appear, measure creatine kinase and stop atorvastatin if it is above 5 times the upper limit of normal (atorvastatin label). Amiodarone interactions persist for weeks to months after it is stopped (amiodarone labels).