Interaction between antidepressants and perphenazine in psychiatric inpatients.

In a study of 99 patients receiving amitriptyline or nortriptyline alone and 60 patients receiving one of these antidepressants in combination with perphenazine, the patients receiving the combination medication had up to 70% higher antidepressant plasma levels than patients receiving the antidepressant alone. The groups did not differ significantly in sex, age, smoking behavior, or antidepressant dose level. Due to the possibility of side effects from such combination medication, the authors recommend that depressed patients not responding to the tertiary amine tricyclic antidepressants receive a trial of high doses of the drugs before antidepressant-neuroleptic combinations are administered.