Comparative Efficacy of Every 2 Weeks versus Every 6 Weeks Injections of Fluphenazine Decanoate

Background: Maintenance treatment of schizophrenia reduces relapse rates of this disease. This treatment is carried out for long periods of time and occasionally for lifelong. Dose reduction strategies are designed to maintain the benefits of antipsychotic drug therapy, while reducing the side effects. The authors tested a new dose reduction approach by increasing the interval between administration of intramuscular (IM) injections of fluphenazine decanoate. Methods: Fifty outpatients with schizophrenia or schizoaffective disorder were randomly assigned to receive 25mg of fluphenazine decanoate intramuscularly, either every 2 weeks or every 6 weeks, for 54 weeks in a double-blind design. Results: The two-dose regimens did not differ significantly in the number of relapses or returning of symptoms, but the 1-year extrapyramidal symptom and dyskinesia scores, adjusted for baseline, were higher for the “every 2 weeks” than the “every 6 weeks” group. Conclusion: The use of injections of fluphenazine, every 6 weeks instead of every 2 weeks, may increase compliance and improve patient’s comfort as well as decreasing cumulative antipsychotic exposure, without increasing relapse rates or symptoms.