The efficacy of intramuscular olanzapine for the rapid treatment of DAA was found to be comparable to that of lorazepam (a benzodiazepine), and better than that of placebo, for institutionalized elderly patients. Adverse events at 24 hours were the same for all three patient groups.
Over the longer term (6 to 12 weeks), the evidence regarding the efficacy, measured using behavioural scales in elderly patients, of olanzapine and risperidone compared to placebo was variable: some trials showed benefit and some did not. Both drugs increased some types of side effects.
In two 12-week trials in elderly patients with DAA, risperidone was compared to the conventional antipsychotic agent haloperidol. Efficacy was similar with both drugs. However, haloperidol increased the incidence of extrapyramidal symptoms significantly.
DAA is a long-term condition often requiring treatment for years, yet trials have been relatively short (6 to 12 weeks).
Health Canada has recently advised that elderly dementia patients on risperidone may have an increased risk of cerebrovascular adverse events.
Novel antipsychotics are expensive drugs, relative to more established alternatives. Cost-effectiveness analyses may clarify relative costs and benefits.