The use of antipsychotic and anticholinergic antiparkinson drugs in Norway after the withdrawal of orphenadrine.
OBJECTIVE
Extrapyramidal side-effects induced by antipsychotic drugs are treated with dose reduction or substitution with another antipsychotic drug or by the addition of anticholinergic antiparkinson agents. The withdrawal of orphenadrine from the Norwegian market provided a possibility to investigate to what degree these alternative measures were taken in clinical practice.


METHODS
Data were drawn from the Norwegian Prescription Database on the sales of antipsychotics and one of the two anticholinergic antiparkinson agents marketed in 2004, orphenadrine and biperiden, to a total of 39 758 outpatients. The patients were reinvestigated in 2007. The consequences of the withdrawal of orphenadrine from the Norwegian market in 2005 regarding dosing, switching and cessation of antipsychotics and use of anticholinergics were assessed for orphenadrine users compared with biperiden users.


RESULTS
Of the patients originally using orphenadrine, 28.4% stopped using the drug without reducing the antipsychotic dose or replacing orphenadrine with another anticholinergic agent. The corresponding number for biperiden users was 19.3%. Only 11.8% of patients switched to another antipsychotic drug, but they used significantly lower antipsychotic doses than those who stayed on the same drug.


CONCLUSIONS
The use of anticholinergic antiparkinson agents could be seen as superfluous for at least one-third of patients.
Gjerden
Pål
P
Department of Psychiatry, Telemark Hospital, Skien N-3710, Norway. pal.gjerden@sthf.no
Slørdal
Lars
L
Bramness
Jørgen G
JG
D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D018680:Cholinergic Antagonists / Q000008:administration & dosage / Q000009:adverse effects*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D009664:Norway / Q000453:epidemiology; D009966:Orphenadrine / Q000008:administration & dosage / Q000009:adverse effects*; D010300:Parkinson Disease / Q000188:drug therapy* / Q000453:epidemiology; D010818:Practice Patterns, Physicians'; D056737:Safety-Based Drug Withdrawals; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy* / Q000523:psychology
D014150:Antipsychotic Agents; D018680:Cholinergic Antagonists; D009966:Orphenadrine
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