Terbinafine markedly increased the AUC of desipramine in one study. Case reports describe increases in the
serum levels of amitriptyline, desipramine, imipramine, and nortriptyline, with associated
toxicity, in patients given oral
terbinafine.
Monitor for any increase in the adverse effects of the tricyclic, and be aware that the dosage may need to be decreased, sometimes substantially. Note that an interaction may occur for a number of weeks after stopping terbinafine, because it has a long
half-life.