Effects of trazodone treatment on alpha-2 adrenoceptor function in depressed patients.

Tricyclic antidepressant drugs reduce the sensitivity of alpha 2 adrenoceptors during long-term treatment. In the present study, the alpha 2 adrenergic agonist clonidine was administered to 11 depressed patients before and during treatment with the triazolopyridine antidepressant trazodone (TRZ). Clonidine's ability to decrease blood pressure (BP) and plasma levels of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), and to increase sedation and plasma growth hormone (GH), were measured. TRZ had little effect on these indices of pre- and postsynaptic alpha 2 receptor function, suggesting that the antidepressant properties of TRZ are not related to changes in alpha 2 adrenoceptor sensitivity.