Concurrent use of statins and amiodarone.

OBJECTIVE: To estimate the concurrent use between statins and amiodarone in context with published case reports of drug-interaction-induced rhabdomyolysis.

DESIGN: Retrospective analysis of a longitudinal prescription claims database for concurrent prescriptions of statins and amiodarone dispensed during 2006.

PATIENTS, PARTICIPANTS: The study population includes an unprojected annual number of patients who filled a prescription for an HMG CoA reductase inhibitor or simvastatin-containing products or lovastatin-containing products or Lipitor (atorvastatin) or Caduet (amlodipine/atorvastatin) concurrently with brand and generic forms of amiodarone during 2006. The concurrency analysis was used to provide context for published case reports of rhabdomyolysis/myopathy related to simvastatin and amiodarone concurrent use.

MAIN OUTCOME MEASURE: Episodes of concurrent use between statins and amiodarone.

RESULTS: Findings from this analysis indicate noteworthy amiodarone and statin concurrency (44%) when based on amiodarone patient volume. Atorvastatin had the greatest level of concurrency (23.5%) with amiodarone followed by simvastatin (13.3%). Proportionality based on amiodarone patient volume shows a greater level of concurrency with 20 mg (6%) and 40 mg (5.5%) simvastatin strengths compared with other simvastatin strengths.

CONCLUSION: Clinicians should be vigilant in monitoring the regimens of patients prescribed a statin with drugs that may increase the risk of myopathy. In particular, since nearly half of the patients prescribed amiodarone may also be prescribed a statin, then addition of amiodarone or changes in statin dose should trigger a drug regimen review and patient level monitoring. Clinicians should avoid simvastatin doses greater than 20 mg per day in patients taking amiodarone.