title: Methadone prolongs cardiac conduction in young patients with cancer-related pain.
abstract: OBJECTIVE
  Methadone prolongs cardiac conduction, from mild corrected QT (QTc) prolongation to torsades de pointes and ventricular fibrillation, in adults. However, methadone use for pain and its effects on cardiac conduction have not been investigated in pediatric populations.
  
  
  METHODS
  A retrospective review of QTc intervals in patients receiving methadone analgesia was conducted. Medical records from a 4-year period (September 2006 to October 2010) at a pediatric oncology institution were reviewed, and correlations were tested between cardiac conduction and methadone dosage and duration of therapy, electrolyte levels, renal and hepatic dysfunction, and concurrent medications.
  
  
  RESULTS
  Of the 61 patients who received methadone, 37 met our inclusion criteria and underwent 137 electrocardiograms (ECGs). During methadone treatment, the mean QTc was longer than that at baseline (446.5 vs 437.55 ms). The mean methadone dose was 27.0±24.3 mg/d (range, 5-125 mg/d; median, 20 mg/d) or 0.47±0.45 mg/kg per day (range, 0.05-2.25 mg/kg per day; median, 0.37 mg/kg per day), and the mean duration of therapy was 49 days. The authors identified a correlation between automated and manual ECG readings by two cardiologists (Pearson r=0.649; p<0.0001), but the authors found no correlations between methadone dose or duration and concurrent QTc-prolonging medications, sex, age, electrolyte abnormalities, or renal or hepatic dysfunction.
  
  
  CONCLUSIONS
  At a clinically effective analgesic dose, methadone dosage and duration were not correlated with QTc prolongation, even in the presence of other risk factors, suggesting that methadone use may be safe in pediatric populations. The correlation between automated and manual ECG readings suggests that automated ECG readings are reliable for monitoring cardiac conductivity during the reported methadone-dosage regimens.
authors.affiliation: Member, Department of Pediatric Medicine, Division of Anesthesiology, St Jude Children's Research Hospital, Memphis, Tennessee; Director, Pain Management Service, St Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Doralina L
authors.initials: DL
authors.lastname: Anghelescu
authors.affiliation: Pediatric Oncology Education Student, St Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Rakesh M
authors.initials: RM
authors.lastname: Patel
authors.affiliation: Palliative Care Fellow, Division of Quality of Life and Palliative Care, St Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Mahoney
authors.affiliation: Assistant Member, Department of Pediatric Medicine, Division of Anesthesiology, St Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Luis
authors.initials: L
authors.lastname: Trujillo
authors.affiliation: Clinical Research Associate, Division of Anesthesiology, St Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Lane G
authors.initials: LG
authors.lastname: Faughnan
authors.affiliation: Clinical Research Associate, Division of Anesthesiology, St Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Brenda D
authors.initials: BD
authors.lastname: Steen
authors.affiliation: Associate Member, Departments of Oncology and Pediatric Medicine, St Jude Children's Research Hospital, Memphis, Tennessee; Director, Division of Quality of Life and Palliative Care, St Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Justin N
authors.initials: JN
authors.lastname: Baker
authors.affiliation: Lead Senior Biostatistician, Department of Biostatistics, St Jude Children's Research Hospital, Memphis, Tennessee.
authors.forename: Deqing
authors.initials: D
authors.lastname: Pei
mesh_terms: D000200:Action Potentials; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D059350:Chronic Pain / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007223:Infant; D008297:Male; D008691:Methadone / Q000008:administration & dosage / Q000009:adverse effects*; D009369:Neoplasms / Q000150:complications*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone