Torsade de pointes associated with very-high-dose methadone.
BACKGROUND
Methadone is an effective treatment for opioid dependency and chronic pain. A methadone derivative, levacetylmethadol, was withdrawn from the European market after being associated with torsade de pointes. To date, no association between methadone and this arrhythmia has been described.


OBJECTIVE
To evaluate a series of methadone-treated patients experiencing torsade de pointes.


METHODS
Retrospective case series.


METHODS
Methadone maintenance treatment programs in the United States and a pain management center in Canada.


METHODS
17 methadone-treated patients who developed torsade de pointes.


METHODS
Chart review for concomitant arrhythmia risk factors and quantification of corrected QT interval (QTc).


RESULTS
The mean daily methadone dose was 397 +/- 283 mg, and the mean QTc interval was 615 +/- 77 msec. Fourteen patients had a predisposing risk factor for arrhythmia. A cardiac defibrillator or pacemaker was placed in 14 patients; all 17 patients survived.


CONCLUSIONS
This series raises concern that very-high-dose methadone may be associated with torsade de pointes. Given the likely expansion of methadone treatment into primary care, further investigation of these findings is warranted.
Krantz
Mori J
MJ
Denver Health Medical Center, and The University of Colorado Health Sciences Center, Bannock Street, Mailcode 0960, Denver, CO 80204-4507, USA.
Lewkowiez
Laurent
L
Hays
Helen
H
Woodroffe
Mary Ann
MA
Robertson
Alastair D
AD
Mehler
Philip S
PS
D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects*; D002170:Canada; D002908:Chronic Disease; D004562:Electrocardiography; D005260:Female; D006556:Heroin Dependence / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008691:Methadone / Q000008:administration & dosage / Q000009:adverse effects*; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy; D012189:Retrospective Studies; D012307:Risk Factors; D016171:Torsades de Pointes / Q000139:chemically induced* / Q000175:diagnosis; D014481:United States
D000701:Analgesics, Opioid; D008691:Methadone