Pressor responses to tyramine and norepinephrine after subchronic administration of fluoxetine to man.

The effects of subchronic, oral administration of fluoxetine (60 mg daily for 45 days) were studied in three healthy male volunteers. The pressor responses to intravenous bolus tyramine injections or norepinephrine infusions were assessed during the one-week placebo period, periodically after daily fluoxetine dosing, and then for 11 days post-fluoxetine dosing. The dose-pressor responses, determined from the incremental elevation of systolic blood pressure, were unchanged in each of the three dosing intervals. These results indicate that fluoxetine does not significantly impair the catecholamine uptake mechanism in the peripheral adrenergic neuron on acute or subchronic dosing, nor is any rebound-increased sensitivity evident after subchronic administration. Further, fluoxetine does not appear to demonstrate peripheral alpha-adrenolytic properties in man.