Vitamin B6 and B12 in the Treatment of Movement Disorders Induced by Antipsychotics

Overview

D2 dopaminergic receptor blockers, used to treat schizophrenia, can lead to the onset of movement disorders. Drug-induced movement disorders encompass several syndromes. Parkinsonism, dystonia, dyskinesia and akathisia are the most prevalent. All of them lead to poor adherence to the treatment instituted, decrease in the quality of life, relapses and hospitalizations. The pathophysiology of drug-induced movement disorders is complex and poorly understood, but seems to be associated with oxidative stress, as a result of an increase in free radicals generated from dopamine metabolism. Treatment strategies following the onset of drug-induced movement disorders include neuroleptic discontinuation, use of atypical antipsychotics and anticholinergics. A pre-clinical study showed that the antioxidant properties of vitamins B6 and B12, alone or in combination, prevented the development of orofacial dyskinesia induced by haloperidol. This clinical trial aims to evaluate the effects of vitamins B6 and B12 on the treatment of patients diagnosed with schizophrenia, schizoaffective or bipolar disorder who present with tardive dyskinesia, dystonia and parkinsonism.

D2 dopaminergic receptor blockers, used to treat schizophrenia, can lead to the onset of drug-induced movement disorders, such as parkinsonism, dystonia, dyskinesia and akathisia. They seem to be associated with oxidative stress, as a result of an increase in free radicals generated from dopamine metabolism. A preclinical study showed that vitamin B6 (pyridoxine) and B12 (cobalamin), alone or in combination, prevented the development of orofacial dyskinesia induced by haloperidol in an animal model of schizophrenia. Specific Aim1: To conduct a prospective, randomized, double-blind, placebo-controlled trial to evaluate the efficacy of 12-week adjuvant treatment with 200mg of pyridoxine (B6) or 2mg of cobalamin (B12) to treat drug-induced movement disorders of patients with schizophrenia, schizoaffective or bipolar disorder. The investigators will randomly assign 45 patients into three groups: placebo, B6 or B12 and check whether administration of vitamin B6 (pyridoxine) or B12 (cobalamin) attenuates drug-induced movement disorders (IDDM) in patients with diagnosis of schizophrenia, schizoaffective or bipolar disorder. Specific Aim 2: To quantify changes in serum markers of inflammation and biomarkers of oxidative stress in response to adjunctive treatment with B6 or B12. The hypothesis is that changes in these biomarkers will mediate the clinical response to them. Research Plan: The investigators will carry out a proof of concept 12-week prospective, randomized, double-blind, controlled trial of vitamin B6 and B12, at doses of 200 mg/day and 2mg/day, respectively, or identical placebo tablets, added to ongoing antipsychotics in 45 stable patients (ages 18-60 years, 15 patients per group) with diagnosis of schizophrenia, schizoaffective or bipolar disorder. The study will be conducted at the Drug Research and Development Center (NPDM), at the Universidade Federal do Ceará, Fortaleza, Brazil. This center has a long history of performing placebocontrolled trials in clinical medicine (http://www.npdm.ufc.br/) and has the necessary infrastructure to successfully complete the proposed study protocol. All participants will give written informed consent prior to study enrollment.