Effect of switching antipsychotics on antiparkinsonian medication use in schizophrenia: a population-based study

Background: The extent to which atypical antipsychotics have a lower incidence of extrapyramidal symptoms than typical antipsychotics has not been well-evaluated in community practice. Aims: To examine the effects of switching antipsychotics on antiparkinsonian medication use among individuals with schizophrenia in UK general practices. Method: We included those switched from typical to atypical antipsychotics (n=209) or from one typical antipsychotic to another (n=261) from 1994 to 1998. Results: Antiparkinsonian drug prescribing dropped by 9.2% after switching to atypical antipsychotics (P<0.0001). Switching to olanzapine decreased the rate by 19.2% (P<0.0001), but switching to risperidone had no impact. After switching from one typical antipsychotic to another, antiparkinsonian drug prescribing increased by 12.9% (P