title: Antipsychotic-induced extrapyramidal syndromes and cytochrome P450 2D6 genotype: a case-control study.
abstract: To study the association between polymorphism of the cytochrome P450 2D6 gene (CYP2D6) and the risk of antipsychotic-induced extrapyramidal syndromes, as measured by the use of antiparkinsonian medication. Data for this case-control study were obtained from a psychiatric hospital where newly admitted patients are routinely screened for several CYP2D6 mutant alleles. Cases were patients prescribed antiparkinsonian medication during oral antipsychotic drug treatment in the period September 1994 to August 2000. They were divided into those using an antipsychotic drug the metabolic elimination of which depends on the activity of the CYP2D6 enzyme ('CYP2D6-dependent') and those using other antipsychotic drugs. We formed a control group of antipsychotic drug users for both case groups using a matching ratio of 3 : 1 (controls : cases). Control patients were matched on whether or not their prescribed antipsychotic drug was CYP2D6-dependent. Odds ratios for patients who were slow metabolizers versus patients who were extensive metabolizers were calculated using conditional logistic regression and were adjusted for age, gender, dose and other potential confounding factors. We identified 77 case patients who were prescribed a CYP2D6-dependent antipsychotic drug and 54 case patients who were prescribed non CYP2D6-dependent antipsychotic drugs. Among the case- and control-patients using a CYP2D6-dependent antipsychotic drug, the poor metabolizers were more than four times more likely to start with antiparkinsonian medication than the extensive metabolizers (odds ratio 4.44; 95% confidence interval 1.11-17.68). An increased risk was not observed for patients using non CYP2D6-dependent antipsychotic drugs (odds ratio 1.20; 95% confidence interval 0.21-6.79). Genetically impaired CYP2D6 activity can increase the risk of antipsychotic-induced extrapyrimidal syndromes. Poor metabolizers should have their antipsychotic drug dosage reduced when the metabolism of the prescribed drug depends on CYP2D6 activity or should receive an antipsychotic drug that is not CYP2D6-dependent.
authors.affiliation: Department of Pharmacoepidemiology & Pharmacotherapy, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands. i.e.r.m.schillevoort@pharm.uu.nl
authors.forename: Igor
authors.initials: I
authors.lastname: Schillevoort
authors.forename: Anthonius
authors.initials: A
authors.lastname: de Boer
authors.forename: Jan
authors.initials: J
authors.lastname: van der Weide
authors.forename: Linda S W
authors.initials: LS
authors.lastname: Steijns
authors.forename: Raymund A C
authors.initials: RA
authors.lastname: Roos
authors.forename: Paul A F
authors.initials: PA
authors.lastname: Jansen
authors.forename: Hubert G M
authors.initials: HG
authors.lastname: Leufkens
mesh_terms: D000328:Adult; D000978:Antiparkinson Agents / Q000378:metabolism / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000378:metabolism; D001480:Basal Ganglia Diseases / Q000139:chemically induced* / Q000188:drug therapy / Q000201:enzymology; D016022:Case-Control Studies; D015331:Cohort Studies; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013577:Syndrome
chemical_list: D000978:Antiparkinson Agents; D014150:Antipsychotic Agents; D019389:Cytochrome P-450 CYP2D6