Effects of amiodarone on the pharmacokinetics and toxicity of digoxin in laboratory animals.

Some pharmacokinetic interactions between digoxin and amiodarone were studied in experiments on rabbits. An increase of digoxin serum levels was established in amiodarone-treated rabbits (amiodarone 30 mg/kg s.c. for five days alone or together with digoxin). The calculated elimination half-life (t 1/2) and the area under the curve (AUC) of digoxin were increased and the digoxin clearance was decreased, being most pronounced in animals receiving amiodarone-digoxin combination for five days. There were no changes either in digoxin toxicity in amiodarone-treated guinea pigs or in serum levels of T4, T3 and TTH. The possible mechanisms of digoxin-amiodarone interactions are discussed.