Calcium channel blockers for neuroleptic-induced tardive dyskinesia

Background Schizophrenia and related disorders affect a sizable proportion of any population. Neuroleptic (antipsychotic) medications are the primary treatment for these disorders. Neuroleptic medications are associated with a variety of side effects including tardive dyskinesia. Dyskinesia is a disfiguring movement disorder of the orofacial region that can be tardive (having a slow or belated onset). Tardive dyskinesia is difficult to treat, despite experimentation with several treatments. Calcium channel blockers (diltiazem, nifedipine, nimodipine, verapamil) have been among these experimental treatments. Objectives To determine the effects of calcium-channel blocker drugs (diltiazem, nifedipine, nimodipine, verapamil) for treatment of neuroleptic-induced tardive dyskinesia in people with schizophrenia, schizoaffective disorder or other chronic mental illnesses. Search strategy We updated previous searches in May 2010 by searching the Cochrane Schizophrenia Group Register using the Cochrane Schizophrenia Group search strategy. Selection criteria Randomised clinical trials comparing calcium-channel blockers with placebo, no intervention or any other intervention for people with both tardive dyskinesia and schizophrenia or serious mental illness. Data collection and analysis We planned to extract and analyse data on an intention-to-treat (ITT) basis. We intended to calculate the relative risk (RR) and 95% confidence intervals (CI) of homogeneous dichotomous data using a random-effects model, and, where possible, calculate the number needed to treat. We planned to calculate mean differences (MD) for continuous data. Main results We did not include any trials in this review. We excluded 15 studies; eight were not randomised, one did not use calcium channel blockers, five small, randomised, studies reported no usable data and one did not include people with both tardive dyskinesia and schizophrenia. Authors' conclusions The effects of calcium-channel blockers for antipsychotic induced tardive dyskinesia are unknown. Their use is experimental and should only be given in the context of well designed randomised clinical trials.