Context: Methadone has been reported to prolong the corrected QT (QTc) interval and increase the risk of torsades de pointes.
Objectives: Our study examined the frequency of QTc prolongation among pediatric and young adult patients starting methadone for cancer pain.
Methods: All patients followed a standardized protocol. Electrocardiograms (ECGs) were obtained at baseline (methadone starting day to 14 days prior), 1-2 weeks, and 4-6 weeks later. QTc values were manually calculated using the Bazett formula. QTc prolongation was defined as ≥460 milliseconds (ms) for prepubertal children, ≥470 ms for pubertal males, and ≥480 ms for pubertal females.
Results: Baseline ECGs were completed in 42 patients. Follow-up ECGs were completed in 38 of 42 (91%) and 31 of 42 (74%) patients at 1-2 weeks and 4-6 weeks, respectively. No patients had prolongation of the QTc at baseline, and 1 of 38 (3%) patients had a prolonged QTc at weeks 1-2. This patient had a history of prolonged QTc that the family did not initially report. No patients had prolongation of the QTc at weeks 4-6. No patients had torsades de pointes or ventricular fibrillation, and none died suddenly. Median (interquartile range [IQR]) baseline QTc was 391 (377-400) ms; median (IQR) 1-2 week follow-up QTc was 399 (374-411) ms (P = .05), and median (IQR) 4-6 week follow-up QTc was 393 (379-423) ms (P = .01).
Conclusion: Clinically significant prolongation of the QTc interval occurred only in one patient who had a history of prolonged QTc. Prolonged QTc is rare in this population.
Keywords: Palliative Care; cardiotoxicity; pain management; pediatric; pediatric oncology.
Copyright © 2019 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.