Levomepromazine is an ‘older’ typical antipsychotic licensed for use in schizophrenia but sparingly prescribed in the UK. Our objective is to determine the clinical effects and safety of levomepromazine compared with placebo or antipsychotics for schizophrenia and schizophreniform psychoses. All randomised trials comparing levomepromazine with placebo or other antipsychotics for schizophrenia and schizophreniform psychoses were included in our systematic review which currently includes 4 RCTs with 192 participants. For our primary outcome of leaving the study early, levomepromazine was not significantly different compared with other antipsychotics. The levomepromazine arm was significantly better on CGI severity compared with chlorpromazine (n = 38, 1 RCT, WMD -0.80 CI -1.51 to -0.09). Recipients given levomepromazine had a better BPRS endpoint score (n = 38, 1 RCT, WMD -9.00, CI -17.46 to -0.54) and PANSS total score (n = 38, 1 RCT, WMD -15.90, CI -30.30 to -1.50) than chlorpromazine. Levomepromazine caused less tremor (n = 41, 1 RCT RR 0.12 CI 0.02 to 0.87 NNTB 3 CI 2 to 8), less antiparkinsonian medication administration (n = 79, 2 RCTs, RR 0.39 CI 0.17 to 0.90, NNTB 5, CI 2 to 21) compared with haloperidol.

Levomepromazine caused less akathisia compared with chlorpromazine, but more hypotension compared with risperidone (n = 42, 1 RCT, RR 2.50 CI 1.21 to 5.18, NNTH 3, CI 2 to 7). Dizziness was common with levomepromazine compared with other antipsychotic medications. Available data does not enable us to confidently comment on the effectiveness of levomepromazine for schizophrenia. Larger, more robust, studies comparing levomepromazine with other antipsychotics including clozapine are much needed.