EFFECT OF FLUVOXAMINE, IMIPRAMINE AND PLACEBO ON CATECHOLAMINE FUNCTION IN DEPRESSED OUTPATIENTS

Many of the specific serotonin reuptake inhibitors appear to have some effect on noradrenergic function. Fluvoxamine is one of the newer age nts and its specificity has not been fully assessed. Depressed patient s participating in a study comparing the efficacy of fluvoxamine with imipramine and placebo collected 24 hour urine samples (N = 38) and ha d plasma samples drawn (N = 38) prior to and after 6 weeks of double b lind treatment. Urine samples were analyzed for 24 hour output of MHPG , VMA, NMN, MN and HVA. Plasma samples were analyzed for NE levels. Im ipramine treatment produced a reduction in urinary MHPG, an increase i n the ratio of NMN to MHPG plus VMA, and a trend towards an increase i n plasma NE which was significantly different than the effects seen in the fluvoxamine and placebo groups. There was an additional finding i n the imipramine group of a significant correlation between percentage change in plasma NE and clinical improvement. Fluvoxamine treatment, on the other hand, produced no clear effect on any measure of noradren ergic function and the antidepressant efficacy of fluvoxamine was unre lated to any noradrenergic variable. These findings lend support to th e hypothesis that fluvoxamine does not have significant effects on nor adrenergic function.