title: Measurement of QTc in patients receiving chronic methadone therapy.
abstract: Recent reports suggest that methadone may prolong the QTc interval and cause torsades de pointes. This study was conducted to evaluate the prevalence of QTc prolongation during oral methadone therapy and identify factors associated with prolongation. Patients receiving oral methadone as treatment for chronic pain or addiction were eligible for the study. One hundred four patients who were receiving > or = 20 mg methadone per day for > or = 2 weeks underwent electrocardiograms to measure QTc interval duration. Sixty-three (61%) patients were male and 63 (61%) were receiving methadone maintenance for opioid addiction. The mean (+/- SD) age was 45.3 +/- 9.4 years. The median (range) methadone dose was 110 mg/day (20-1200 mg/day); median (range) number of months on methadone was 12.5 months (1-444 months). The median (range) QTc interval was 428 msec (396-494 msec). Thirty-three percent had QTc prolongation (males 40%, females 20%; P=0.03). No patient had a QTc longer than 500 msec. Significant dose response was observed in males on methadone <12 months (rho=0.60, P=0.02). Our study suggests that methadone may prolong the QTc interval in specific subpopulations but poses little risk of serious prolongation.
authors.affiliation: Department of Pain Medicine and Palliative Care, Beth Israel Medical Center, New York, New York 10003, USA.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Cruciani
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Sekine
authors.forename: Peter
authors.initials: P
authors.lastname: Homel
authors.forename: David
authors.initials: D
authors.lastname: Lussier
authors.forename: Ysmael
authors.initials: Y
authors.lastname: Yap
authors.forename: Yukako
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Paul
authors.initials: P
authors.lastname: Schweitzer
authors.forename: Stanley R
authors.initials: SR
authors.lastname: Yancovitz
authors.forename: Jeanne A
authors.initials: JA
authors.lastname: Lapin
authors.forename: Lauren
authors.initials: L
authors.lastname: Shaiova
authors.forename: Robert G
authors.initials: RG
authors.lastname: Sheu
authors.forename: Russell K
authors.initials: RK
authors.lastname: Portenoy
mesh_terms: D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006556:Heroin Dependence / Q000188:drug therapy; D006801:Humans; D008297:Male; D008691:Methadone / Q000009:adverse effects* / Q000627:therapeutic use*; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016171:Torsades de Pointes / Q000139:chemically induced* / Q000175:diagnosis*
chemical_list: D008691:Methadone