Effect of switching antipsychotics on antiparkinsonian medication use in schizophrenia: 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.


OBJECTIVE
To examine the effects of switching antipsychotics on antiparkinsonian medication use among individuals with schizophrenia in UK general practices.


METHODS
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<0.0001).


CONCLUSIONS
Reduction in antiparkinsonian medication use after switching to atypical antipsychotics was substantial in community practice but not as large as in randomised controlled trials. The rate of reduction varied according to the type of medication.
Park
Sylvia
S
Department of Ambulatory Care and Prevention, Harvard Medical School and Harvard Pilgrim Health Care, Boston, MA, USA. sylviap@khidi.or.kr
Ross-Degnan
Dennis
D
Adams
Alyce S
AS
Sabin
James
J
Kanavos
Panos
P
Soumerai
Stephen B
SB
D000328:Adult; D000367:Age Factors; D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage*; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001480:Basal Ganglia Diseases / Q000188:drug therapy*; D001569:Benzodiazepines / Q000627:therapeutic use; D002746:Chlorpromazine / Q000627:therapeutic use; D018492:Dopamine Antagonists / Q000627:therapeutic use; D004334:Drug Administration Schedule; D005194:Family Practice; D005260:Female; D006220:Haloperidol / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077152:Olanzapine; D018967:Risperidone / Q000627:therapeutic use; D012559:Schizophrenia / Q000188:drug therapy*; D012737:Sex Factors
D000978:Antiparkinson Agents; D014150:Antipsychotic Agents; D018492:Dopamine Antagonists; D001569:Benzodiazepines; D006220:Haloperidol; D018967:Risperidone; D000077152:Olanzapine; D002746:Chlorpromazine