Carbamazepine kinetics in cardiac patients before and during amiodarone

Carbamazepine and amiodarone may often be used together, especially in countries where cardiomyopathies are common. In this study single doses of carbamazepine (400 mg) were given to patients with cardiac disease before and after one month of therapy with amiodarone, 400 mg daily. The kinetic profile of carbamazepine, its free fraction, and serum amiodarone, were measured at the two occasions. There was no statistically significant change in carbamazepine kinetics or free fraction, before and after the introduction of amiodarone. The concentrations of amiodarone after one month of therapy were low. It is suggested that the possible interaction in the hepatic metabolism was not demonstrated because amiodarone concentrations were not enough to inhibit carbamazepine metabolism.