How much are atypical antipsychotic agents being used, and do they reach the populations who need them? A Canadian experience.

BACKGROUND: The introduction of new antipsychotic agents in the past decade has helped alter the treatments available to 2 vulnerable populations-those with schizophrenia and related psychotic conditions and elderly individuals with dementia.
OBJECTIVE: After examining overall trends in antipsychotic use, this analysis reviews patterns of atypical antipsychotic use in the elderly and financially disadvantaged populations of Ontario. It identifies affected subpopulations and offers several interpretations of how observed patterns of use reflect outpatient prescribing practices.
METHODS: This study used drug claims data from the Ontario Drug Benefit (ODB) program for the years 1992 to 1998. The use of antipsychotic agents was followed for 2 years in a subpopulation of ODB participants identified as consistent users of these agents (ie, those with evidence of > 1-time use).
RESULTS: During the study period, the total number of ODB claimants grew by 1%, the number of claimants using antipsychotic agents increased by approximately 25%, and the expenditure per claimant in this group increased by nearly 250%. Much of this growth in expenditures was associated with use of the newer atypical antipsychotic agents olanzapine, risperidone, and quetiapine. Compared with patients aged > or = 65 years, those aged < 65 years were more likely to receive an initial prescription for an atypical antipsychotic or be switched to an atypical antipsychotic. However, the proportion of patients aged > 85 years consistently using antipsychotic agents was greater than predicted based on the proportion of the ODB population they represent. These patients were more likely to use conventional antipsychotic agents exclusively.
CONCLUSIONS: The introduction of the atypical antipsychotic agents was paralleled by a striking increase in ODB expenditures for antipsychotic drugs, although use of these agents was not consistent across age groups. There was more switching to atypical antipsychotics, as well as greater use in general, among younger compared with older patients, despite evidence that the atypical antipsychotics may be safer in the elderly than conventional antipsychotics. Guideline dissemination may be an important way of familiarizing clinicians with the atypical agents. Health care systems should be aware of the potential for a substantial increase in health care costs with more widespread adoption of these medications.