The use of antipsychotic and anticholinergic antiparkinson drugs in Norway after the withdrawal of orphenadrine

• Published in: British journal of clinical pharmacology Vol. 68; no. 2; pp. 238 - 242
• Main Authors: Gjerden, Pål, Slørdal, Lars, Bramness, Jørgen G.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.08.2009; Blackwell; Blackwell Science Inc
• Subjects: adverse effects; anticholinergic agents; antiparkinson agents; antipsychotic agents; Antipsychotic Agents - administration & dosage; Antipsychotic Agents - adverse effects; Biological and medical sciences; Cholinergic Antagonists - administration & dosage; Cholinergic Antagonists - adverse effects; Drug Administration Schedule; extrapyramidal side‐effects; Female; Humans; Male; Medical sciences; Nervous system (semeiology, syndromes); Nervous system as a whole; Neurology; Norway - epidemiology; Orphenadrine - administration & dosage; Orphenadrine - adverse effects; Parkinson Disease - drug therapy; Parkinson Disease - epidemiology; Pharmacology. Drug treatments; Practice Patterns, Physicians; Safety-Based Drug Withdrawals; Substance Withdrawal Syndrome - drug therapy; Substance Withdrawal Syndrome - psychology; Therapeutics; Norway; Europe; Drug; Nervous system diseases; Neuroleptic; Psychotropic; Toxicity; anticholinergic agents; Orphenadrine; antipsychotic agents; Antihistaminic; Antiparkinson agent; Cerebral disorder; extrapyramidal side-effects; Anticholinergic agent; antiparkinson agents; Central nervous system disease; Secondary effect; adverse effects; Antipsychotic; Antagonist; Anticholinesterase agent; H1 Histamine receptor; Extrapyramidal syndrome
• ISSN: 0306-5251; 1365-2125; 1365-2125
• DOI: 10.1111/j.1365-2125.2009.03446.x

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Extrapyramidal side‐effects induced by antipsychotic agents are treated with dose reduction, switching of antipsychotic medication or the addition of anticholinergic antiparkinson drugs. WHAT THIS STUDY ADDS • The use of anticholinergic antiparkinson drugs appears to be superfluous in a large number of patients. AIMS 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. CONCLUSION The use of anticholinergic antiparkinson agents could be seen as superfluous for at least one‐third of patients.