ECONOMIC-EVALUATION OF ZUCLOPENTHIXOL ACETATE COMPARED WITH INJECTABLE HALOPERIDOL IN SCHIZOPHRENIC-PATIENTS WITH ACUTE-PSYCHOSIS

Zuclopenthixol acetate is a rapid-acting, injectable neuroleptic drug with a duration of action that allows for administration once every 2 to 3 days, in contrast to injectable haloperidol, which may require ad ministration more than once daily. To assess the place of zuclopenthix ol acetate in the treatment of acute episodes of schizophrenia, a cost -consequence analysis was performed comparing this new medication with short-acting, injectable haloperidol. The perspective of the Quebec h ealth care system was adopted. The study population comprised patients diagnosed with schizophrenia who experienced an acute episode of psyc hosis and who were treated with intramuscular (IM) haloperidol. The st udy assessed patients for 9 days after the start of treatment. The lit erature was the principal source of comparative data about the clinica l outcomes of the two treatments. The total cost associated with zuclo penthixol acetate IM or haloperidol IM was modeled using a decision tr ee built around the number of IM injections required to achieve stabil ization. To establish costs, expert panels were consulted and patients ' files were reviewed for a sample of schizophrenic patients who had b een hospitalized in a large psychiatric or general hospital subsequent to a visit to the emergency department and had received a short-actin g IM neuroleptic drug. Only direct medical costs were considered. Beca use zuclopenthixol acetate was not on the market at the time of the st udy, the file review did not allow for a direct estimate of its relate d costs but did provide an account of haloperidol use. The literature shows that zuclopenthixol acetate is similar to haloperidol with respe ct to the control of psychotic episodes; however, zuclopenthixol aceta te is associated with increased sedation and a lower incidence of extr apyramidal symptoms. Using the base-case estimate for the number of in jections required for stabilization, the incremental cost of zuclopent hixol acetate 50 mg over haloperidol was $25.00 (1995 Canadian dollars ) per patient at the psychiatric hospital and $21.00 per patient at th e general hospital. The results were sensitive to the estimate of the number of injections and the number of minutes of nursing care require d by agitated patients. Zuclopenthixol acetate resulted in cost saving s over haloperidol if it permits a reduction of 25% in minutes of nurs ing care or if 85% of patients require 2 injections or less (45% requi ring 1 injection and 40% requiring 2). However, whichever drug is used , the cost of the injectable neuroleptic represents a small fraction o f the cost of care for acutely psychotic patients.