Zuclopenthixol acetate is a medication used to treat acute symptoms of agitation and aggression in patients with schizophrenia and similar serious mental illnesses. A Cochrane systematic review included 11 randomized controlled trials with 714 participants comparing zuclopenthixol acetate with other standard medications. Results suggest there may be no difference between zuclopenthixol acetate and standard medications (such as haloperidol with promethazine) in the speed of tranquilization at 15 minutes. In early stages (15 minutes), sedation was probably higher in the haloperidol and promethazine group, but in later stages (24 and 48 hours), sedation was higher in the zuclopenthixol acetate group. Additional benzodiazepines were required less frequently in the zuclopenthixol acetate group. The overall quality of evidence ranged from moderate to very low.