title: Changes in QT interval after switching to quetiapine in Japanese patients with schizophrenia.
abstract: OBJECTIVE
  There are few reports regarding quetiapine (QTP)-related QT prolongation. We examined the change in QT interval after switching from aripiprazole (ARP), olanzapine (OLZ), or risperidone (RIS) to QTP.
  
  
  METHODS
  Twenty subjects treated with ARP, OLZ, or RIS were enrolled in the study. Following baseline assessments, which included QT interval and electrolytes, these three drugs were switched to QTP for each subject. The same parameters were evaluated following a switch to QTP.
  
  
  RESULTS
  All 20 patients who had been treated with ARP, OLZ, or RIS were successfully switched to QTP. Significant increases were observed in the total mean corrected QT (QTc) interval after switching (p = 0.014). The coefficient of variation for the extent of change in QTc interval was 1.66. The mean QTc with ARP treatment was significantly increased after QTP treatment (p = 0.004).
  
  
  CONCLUSIONS
  Quetiapine might have a greater effect on QTc interval than other second-generation antipsychotics. However, because there was a considerable variability in the extent of QTc prolongation after switch to QTP, further studies are required to clarify the effect of QTP on QTc interval.
authors.affiliation: Department of Psychiatry, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. yutaro@med.niigata-u.ac.jp
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Takuro
authors.initials: T
authors.lastname: Sugai
authors.forename: Naoki
authors.initials: N
authors.lastname: Fukui
authors.forename: Junzo
authors.initials: J
authors.lastname: Watanabe
authors.forename: Shin
authors.initials: S
authors.lastname: Ono
authors.forename: Nobuto
authors.initials: N
authors.lastname: Tsuneyama
authors.forename: Mami
authors.initials: M
authors.lastname: Saito
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Someya
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D044466:Asian People / Q000208:ethnology; D003987:Dibenzothiazepines / Q000494:pharmacology / Q000627:therapeutic use*; D057915:Drug Substitution / Q000379:methods; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D000069348:Quetiapine Fumarate; D012559:Schizophrenia / Q000188:drug therapy* / Q000208:ethnology / Q000503:physiopathology; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D003987:Dibenzothiazepines; D000069348:Quetiapine Fumarate