Increased risk of extrapyramidal side-effect treatment associated with atypical antipsychotic polytherapy

• Published in: Acta psychiatrica Scandinavica Vol. 113; no. 2; pp. 135 - 141
• Main Authors: Carnahan, R. M., Lund, B. C., Perry, P. J., Chrischilles, E. A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Munksgaard International Publishers 01.02.2006; Blackwell; Blackwell Publishing Ltd
• Subjects: Adolescent; Adult; antipsychotic agents; Antipsychotic Agents - administration & dosage; Antipsychotic Agents - adverse effects; basal ganglia diseases; Basal Ganglia Diseases - chemically induced; Basal Ganglia Diseases - diagnosis; Basal Ganglia Diseases - epidemiology; Benzodiazepines - administration & dosage; Benzodiazepines - adverse effects; Biological and medical sciences; cholinergic antagonists; Clozapine - administration & dosage; Clozapine - adverse effects; Cross-Sectional Studies; Delayed-Action Preparations; Dibenzothiazepines - administration & dosage; Dibenzothiazepines - adverse effects; Drug therapy; Drug Therapy, Combination; Female; Humans; Iowa; Male; Mathematical Computing; Medicaid; Medical sciences; Middle Aged; Models, Statistical; Nervous system (semeiology, syndromes); Nervous system as a whole; Neurology; Neuropharmacology; Pharmacology. Drug treatments; polypharmacy; Product Surveillance, Postmarketing; Psycholeptics: tranquillizer, neuroleptic; Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Psychotic Disorders - drug therapy; Psychotic Disorders - epidemiology; Psychotropic drugs; Quetiapine Fumarate; Regression Analysis; Risk Factors; Risperidone - administration & dosage; Risperidone - adverse effects; Side effects; Statistics as Topic; basal ganglia diseases; Nervous system diseases; Drug combination; Atypical antipsychotic; Neuroleptic; Psychotropic; Central nervous system; Basal ganglion; antipsychotic agents; Cerebral disorder; Chemotherapy; Central nervous system disease; Risk factor; cholinergic antagonists; Combined treatment; Antagonist; polypharmacy; Extrapyramidal syndrome
• ISSN: 0001-690X; 1600-0447
• DOI: 10.1111/j.1600-0447.2005.00589.x

Objective:  To determine whether atypical antipsychotic polytherapy is a risk factor for drug treatment for extrapyramidal side‐effects (anti‐EPS drugs) and whether the risk is attributable to antipsychotic dose. Method:  We studied Iowa Medicaid beneficiaries aged 18–64 years with an active atypical and no conventional antipsychotic on January 1, 2001. The association of atypical antipsychotic polytherapy with anti‐EPS drug treatment was determined. Multiple logistic regression was utilized to adjust for covariates in two models, the first adjusting for age, sex and the specific antipsychotic(s) prescribed, and the second also adjusting for doses. Results:  Among 4400 patients, the unadjusted odds of anti‐EPS treatment were increased two‐fold with polytherapy. Polytherapy remained a risk factor in the first model (OR 1.5, 95% CI 1.1–2.0), but not after adjusting for doses (OR 1.0, 95% CI 0.7–1.4). Conclusion:  Atypical antipsychotic polytherapy is a risk factor for anti‐EPS drug treatment, apparently because of higher cumulative doses.