A Cochrane review [Abstract] 1 included 41 studies with a total of 2 939 subjects. Compared with placebo, loxapine has an antipsychotic effect (Global effect not improved at six weeks: n=78, 2 RCTs, RR 0.30 95% CI 0.1 to 0.6 NNT 3 CI 3 to 5). It is as effective as typical drugs in the short term (4 -12 weeks) (Global effect: n=580, 13 RCTs, RR 0.86 95% CI 0.7 to 1.1; mental state: n=915, 6 RCTs, RR 0.89 95% CI 0.8 to 1.1). Very limited heterogeneous data suggest that, given intramuscularly (IM), loxapine may be at least as sedating as IM haloperidol and thiothixene. Loxapine is also as effective as atypicals (risperidone, quetiapine) (n=468, 6 RCTs, RR mental state not improved 1.07 95% CI 0.8 to 1.5). Adverse effect profile is similar to typicals but loxapine may cause more extrapyramidal adverse effects when compared with atypicals (n=340, 4 RCTs, RR 2.18 95% CI 1.6 to 3.1).
Comment: The quality of evidence is downgraded by study quality (inadequate follow up limited in most studies to 12 weeks).
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