FLUVOXAMINE-INDUCED ALTERATIONS IN PLASMA-CONCENTRATIONS OF IMIPRAMINE AND DESIPRAMINE IN DEPRESSED-PATIENTS

The effect of fluvoxamine maleate, 100 mg/day for 10 days, on plasma c oncentrations of tricyclic antidepressants was studied in 15 depressed patients on maintenance therapy with imipramine (7 pts.) or desiprami ne (8 pts.). In the subgroup treated with imipramine, plasma levels of imipramine increased significantly (p < 0.001) during fluvoxamine coa dministration, while levels of desipramine were not modified. Addition of fluvoxamine to patients on a stable desipramine dosage regimen res ulted in a slight, but statistically not significant, increase in desi pramine plasma concentrations. These results suggest that fluvoxamine is a potent inhibitor of imipramine demethylation, while it has a weak effect on the hydroxylation of desipramine.