Is flunarizine a long-acting oral atypical antipsychotic? A randomized clinical trial versus haloperidol for the treatment of schizophrenia.

BACKGROUND

Flunarizine is known as a nonspecific calcium channel blocker that has been used for decades for the treatment of migraine, vertigo, and cognitive deficits related to cerebrovascular disorders. Flunarizine also has dopamine D2 receptor blocking properties and was effective in animal models of predictive validity for antipsychotics. However, its clinical antipsychotic efficacy has never been investigated.

OBJECTIVE

To evaluate the therapeutic efficacy and tolerability of flunarizine compared to haloperidol in outpatients with stable and chronic DSM-IV-defined schizophrenia and schizoaffective disorder.

METHOD

Seventy patients from 2 centers were randomly assigned and participated in a double-blind, parallel-group, flexible-dose study comparing flunarizine (10-50 mg/day) and haloperidol (2.5-12.5 mg/day) for 12 weeks. Patients were assessed with the Positive and Negative Syndrome Scale (PANSS), the Clinical Global Impressions-Improvement (CGI-I) scale, the Extrapyramidal Symptom Rating Scale (ESRS), a battery for cognitive performance, and laboratory examinations. The study was conducted from September 2004 to May 2007.

RESULTS

Mean doses at endpoint were 29.7 mg/day for flunarizine and 6.4 mg/day for haloperidol. Both groups showed significant symptom improvement during the study, with a reduction of 21% in the flunarizine group and 19% in the haloperidol group in PANSS total scores (p < .05). There were no significant differences in PANSS overall score and all subscales, CGI-I score, or cognitive performance. Dropout rates, ESRS scores, and prolactin levels were not different between groups, but significantly more patients reported emergence of akathisia in the haloperidol group (p = .04), and weight gain was significantly higher with flunarizine (1.2 kg) than with haloperidol (-0.8 kg) (p < .05).

CONCLUSION

This is the first study evaluating the antipsychotic properties of flunarizine, which showed good efficacy and tolerability for the treatment of schizophrenia, with a possible atypical profile. Its unique pharmacokinetic profile as an oral drug with long half-life (2-7 weeks), low cost, and low induction of extrapyramidal symptoms warrants further investigation, particularly in psychiatric patients with low adherence to treatment.