A twenty-week double-blind study was conducted to compare the efficacy and side-effect profile of haloperidol decanoate and fluphenazine decanoate, both given four-weekly, in fifty-one chronic schizophrenic patients. The mean dose of fluphenazine decanoate was 84 mg compared to 122 mg for the haloperidol decanoate group--suggesting a potency ratio of : in this study population. The CPRS sub-scale for schizophrenic symptoms showed a statistically significant improvement (p. less than ) for the haloperidol decanoate group after twenty weeks treatment. A significant difference favouring haloperidol decanoate (p. less than ) was also shown in the CPRS depression sub-scale at the end of the study. No significant between-group differences were found in the incidence of extrapyramidal side-effects at week 20, though consumption of the antiparkinsonian medication orphenadrine was significantly higher (p. less than ) in the fluphenazine decanoate group (mean dose 102 mg) compared to a mean dose of 58 mg for the haloperidol decanoate group. More patients on fluphenazine decanoate gained weight than patients on haloperidol decanoate, but the difference was not statistically significant.
Given these considerations, antipsychotic drugs should be prescribed in a manner that is most likely to minimize the occurrence of tardive dyskinesia. Chronic antipsychotic treatment should generally be reserved for patients who suffer from a chronic illness that 1) is known to respond to antipsychotic drugs, and 2) for whom alternative, equally effective, but potentially less harmful treatments are not available or appropriate. In patients who do require chronic treatment, the smallest dose and the shortest duration of treatment producing a satisfactory clinical response should be sought. The need for continued treatment should be reassessed periodically.