ANTIPSYCHOTIC PRESCRIBING PATTERNS AND THE TREATMENT OF EXTRAPYRAMIDAL SYMPTOMS IN OLDER-PEOPLE

OBJECTIVES: We have previously identified antipsychotic use as a risk factor for the use of both dopaminergic and anticholinergic antiparkin sonian drugs in older people. This study examines whether and how such antipsychotic regimens were adjusted before the addition of an antipa rkinsonian drug. DESIGN: Retrospective comparison study. PARTICIPANTS: There were 1307 antipsychotic users begun on anticholinergic antipark insonian drugs and 345 antipsychotic users begun on dopaminergic drugs ; 1864 antipsychotic users not prescribed antiparkinsonian drugs serve d as comparison subjects. Data were drawn from health care claims of p atients aged 65-99 in the New Jersey Medicaid Program from 1981 to 199 0. MEASUREMENTS: We determined if antipsychotic regimens were disconti nued, reduced in dosage, or modified to reduce extrapyramidal toxicity before the institution of antiparkinsonian therapy. RESULTS: Thirty-f ive percent of the patients begun on dopaminergic drugs had their anti psychotic medication discontinued before beginning antiparkinsonian th erapy; the antipsychotic was discontinued in only 12% of patients who started anticholinergic medications (P < .001). Among the smaller subs et of patients with sufficient duration of antipsychotic exposure to e xamine changes in dose, 54% of patients begun on dopaminergic agents h ad their antipsychotic regimen reduced or discontinued before antipark insonian therapy, whereas 33% of patients begun on anticholinergic age nts had one of these regimen changes (P < .001). Controlling for poten tial clinical and demographic confounders using multivariate logistic regression did not substantively alter these results. CONCLUSIONS: The se data indicate that physicians frequently fail to discontinue or mod ify an antipsychotic regimen before adding a new drug to treat probabl e drug-induced extrapyramidal symptoms. Such prescribing patterns prec eding use of dopaminergic antiparkinsonian drugs suggest that addition of such drugs may represent an inappropriate attempt to treat presume d idiopathic Parkinson's disease in many cases.