Effects of alpha 2-receptor blockade in addition to tricyclic antidepressants in therapy-resistant depression.

It was investigated whether yohimbine, a primarily alpha 2-receptor blocking agent, may have an antidepressant effect when given in addition to tricyclic antidepressants. After at least two unsuccessful preliminary antidepressant treatments for a minimum of 4 weeks each, patients received, in addition to tricyclics, yohimbine in increasing doses for 7 days. None of the five patients investigated demonstrated any improvement in depressive symptomatology and four of the five suffered from such side effects as severe anxiety, inner restlessness, psychomotor agitation, and tremor. During intravenous administration of 2.5 and 20 mg yohimbine, significant increases in norepinephrine values and systolic blood pressure were observed. It was concluded that a combination of yohimbine and tricyclic antidepressants seems to have little indication due to yohimbine's lack of efficacy and the high incidence of side effects in the treatment of severely depressed inpatients.