• In a double-blind, placebo, controlled clinical study, lasting 12 weeks, 48 male and 48 female ambulatory schizophrenic patients were randomly assigned to one of four treatments: placebo; amitriptyline hydrochloride, 125 mg/day; perphenazine, 20 mg/day; or amitriptyline-perphenazine, 20 mg/day. Treatment groups contained an equal number of male and female patients.
Perphenazine alone or in combination was substantially more effective in reducing psychopathological disorder than was the placebo, but there was no evidence to indicate the superiority of the amitriptyline-perphenazine combination over perphenazine alone. Amitriptyline alone was not substantially better than placebo and could not be considered an efficacious medication for the maintenance treatment of these patients. Less response to treatment was made by patients with longer-term records of prior hospitalizations.
Chouinard G, Annable L, Serrano M, Albert JM, Charette R. Amitriptyline-Perphenazine Interaction in Ambulatory Schizophrenic PatientsA Controlled Study of Drug Interaction. Arch Gen Psychiatry. 1975;32(10):1295-1307. doi:10.1001/archpsyc.1975.01760280093009