The Effects of a 50% Reduction of Cis(z)-Flupenthixol Decanoate in Chronic Schizophrenic Patients Maintained on a High Dose Regime

Abstract

Eighteen chronic schizophrenic patients who had shown improvement from increased maintenance dosages of cis(z)-flupenthixol decanoate were entered into a double-blind study in which half of the patients were randomly allocated to be maintained on 50% of their pre-trial dosage. During the 44 week study the reduced dosage group showed increased morbidity and one-third of these patients had a schizophrenic relapse. The greatest deterioration occurred in patients reduced from above to below 200 mg cis(z)-flupenthixol decanoate biweekly. A review of all the patients entered into the study showed a relationship between deterioration of schizophrenic and depressive features and cis(z)-flupenthixol plasma levels which reflected the administered dosage. Prolactin levels in general did not reflect control of schizophrenic symptoms. Side-effects were few, and there was no emergence of tardive dyskinesia. A multicentre trial is needed for further evaluation.