title: Comparison of the effects of thioridazine and mesoridazine on the QT interval in healthy adults after single oral doses.
abstract: We compared the effects of single doses of thioridazine and mesoridazine on the heart rate-corrected QT (QTc) interval in healthy adult volunteers. QTc intervals and plasma concentrations of thioridazine, mesoridazine, and metabolites were measured after single oral doses of thioridazine hydrochloride 50 mg, mesoridazine besylate 50 mg, or placebo in a double-blind, crossover study. Mean maximum increases in the QTc interval following thioridazine (37.3+/-4.1 ms, P=0.023) and mesoridazine (46.6+/-7.4 ms, P=0.021) were similar and significantly greater than following placebo (12.9+/-8.1 ms). The area under the effect-time curve over 8 h following drug administration was similar between the two drugs (129.3+/-22.1 vs 148.3+/-43.0 ms h). In conclusion, thioridazine and mesoridazine are associated with similar effects on the QTc interval.
authors.affiliation: School of Clinical and Laboratory Sciences, University of Newcastle, Newcastle-upon-Tyne, Newcastle, UK.
authors.forename: I S M
authors.initials: IS
authors.lastname: Salih
authors.forename: R H K
authors.initials: RH
authors.lastname: Thanacoody
authors.forename: G A
authors.initials: GA
authors.lastname: McKay
authors.forename: S H L
authors.initials: SH
authors.lastname: Thomas
mesh_terms: D000284:Administration, Oral; D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood / Q000493:pharmacokinetics; D019540:Area Under Curve; D018592:Cross-Over Studies; D018492:Dopamine Antagonists / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood / Q000493:pharmacokinetics; D004311:Double-Blind Method; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D008133:Long QT Syndrome / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D008653:Mesoridazine / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood / Q000493:pharmacokinetics; D008875:Middle Aged; D012016:Reference Values; D013881:Thioridazine / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood / Q000493:pharmacokinetics
chemical_list: D014150:Antipsychotic Agents; D018492:Dopamine Antagonists; D008653:Mesoridazine; D013881:Thioridazine