title: Comparative cardiac safety of low-dose thioridazine and low-dose haloperidol.
abstract: OBJECTIVE
  To compare the rate of ventricular arrhythmia, sudden death and unexplained or unattended death among users of thioridazine and haloperidol.
  
  
  METHODS
  Observational cohort study of thioridazine and haloperidol users in the UK General Practice Research Database (GPRD) using data from 1987 through 29 June 2000. Patients were followed for 30 days following each study prescription. The event of interest was a diagnosis of ventricular arrhythmia, sudden death, or unexplained or unattended death. Cox regression was used to calculate rate ratios (RRs) and 95% confidence intervals (CIs), to examine potential confounding factors, and to examine dose-response relationships.
  
  
  RESULTS
  Use of thioridazine and haloperidol in the GPRD was primarily in older patients, at low dose (median daily dose 31 mg thioridazine, 1.8 mg haloperidol). There was no association between thioridazine use and the rate of ventricular arrhythmia, sudden death, and unexplained or unattended death (adjusted RR 0.9, 95% CI 0.7, 1.1). The rate did not appear to increase with dose for either drug over the range observed.
  
  
  CONCLUSIONS
  These results suggest that low-dose thioridazine and haloperidol have similar cardiac safety.
authors.affiliation: Center for Clinical Epidemiology & Biostatistics, Department of Biostatistics & Epidemiology, and Center for Education & Research in Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. shenness@cceb.med.upenn.edu
authors.forename: Sean
authors.initials: S
authors.lastname: Hennessy
authors.forename: Warren B
authors.initials: WB
authors.lastname: Bilker
authors.forename: Jill S
authors.initials: JS
authors.lastname: Knauss
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Kimmel
authors.forename: David J
authors.initials: DJ
authors.lastname: Margolis
authors.forename: Mary F
authors.initials: MF
authors.lastname: Morrison
authors.forename: Robert F
authors.initials: RF
authors.lastname: Reynolds
authors.forename: Dale B
authors.initials: DB
authors.lastname: Glasser
authors.forename: Brian L
authors.initials: BL
authors.lastname: Strom
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D006220:Haloperidol / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D011379:Prognosis; D012044:Regression Analysis; D013881:Thioridazine / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D014150:Antipsychotic Agents; D006220:Haloperidol; D013881:Thioridazine