Effects of amoxapine on serotonin uptake in human blood platelets of depressed patients and normal controls.

The effect of amoxapine and imipramine on the serotonin (5-HT) uptake of blood platelets from depressed patients and normal controls was studied ex vivo or in vitro, respectively. Amoxapine was approximately one-tenth as potent as imipramine in inhibiting 5-HT uptake in blood platelets from normal controls in vitro. Both drugs inhibited 5-HT uptake in a competitive manner. However, ex vivo studies demonstrated that imipramine produced a mixed inhibition and amoxapine, a competitive inhibition of 5-HT uptake. There was no relationship between the change in the platelet affinity for 5-HT after treatment with amoxapine and clinical response to amoxapine.