Risperidone. A pharmacoeconomic review of its use in schizophrenia

The availability of new atypical antipsychotics, such as risperidone, that have higher acquisition costs than conventional treatments has promoted pharmacoeconomic evaluation of their costs and benefits. Risperidone is reported to have superior efficacy to haloperidol and similar efficacy to other atypical antipsychotics. At dosages < or = 8 mg/day, risperidone is generally associated with a lower risk of extrapyramidal symptoms than conventional antipsychotics and may have a more favourable effect on cognitive function and quality of life. Overall treatment costs during the first year of risperidone treatment were lower than in the previous year in a number of studies in patients with schizophrenia, reflecting a reduction in hospitalisation, although costs slightly increased after risperidone initiation in 2 studies. Total treatment costs were not significantly different with risperidone or conventional antipsychotics in a large, prospective naturalistic study. The use of risperidone in preference to conventional antipsychotics in patients with chronic schizophrenia has been supported by several modelled studies, including a cost-effectiveness analysis that compared risperidone and haloperidol in chronic schizophrenia and a cost-utility study that compared the drug with oral haloperidol, depot haloperidol decanoate and depot fluphenazine decanoate for 1 year's treatment of an initially hospitalised chronic schizophrenic patient with moderate symptoms. In another study, the cost-utility ratio for risperidone versus haloperidol was 24,250 Canadian dollars per quality-adjusted life year (year of costing not stated), but only drug costs were considered. Risperidone had favourable cost-benefit ratios relative to conventional antipsychotic treatment in a study that investigated a scenario in which all patients hospitalised with newly diagnosed schizophrenia received conventional antipsychotic therapy for 6 months, and then those who did not respond received a 6-month trial of risperidone or clozapine. The results of 2 limited decision-analytical models did not favour risperidone. One study compared risperidone with oral haloperidol or depot haloperidol decanoate for the outpatient treatment of a schizophrenic patient with a history of relapse and rehospitalisation. The other compared risperidone, olanzapine and oral haloperidol for the treatment of schizophrenia.

Despite its high acquisition cost, risperidone does not increase, and may even reduce, overall treatment costs of schizophrenia by reducing hospitalisation compared with standard treatment regimens. While further pharmacoeconomic evaluation of risperidone as a first-line agent is required, pharmacoeconomic data overall support its use in patients with chronic schizophrenia.