[Torsade de pointes: a severe and unknown adverse effect in a patient taking methadone].
We present here the case of a young drug-addicted patient, who showed a cardio-respiratory arrest attributed to a torsade de pointe-type ventricular arrhythmia. After excluding the usual causes of such arrhythmia, we concluded that it was consecutive to high-dose methadone intake. Methadone can induce torsade de pointe through two mechanisms: a QT interval prolongation secondary to a bradycardia or a prolongation of the myocardial action potential. When prescribing methadone, one should avoid association with other CYP3A4 inhibiting drugs and, if higher doses are necessary, perform regular EKG screening.
Vodoz
J F
JF
Département de Médecine, CHUV, Lausanne.
Jaquier
F
F
Lamy
O
O
D000328:Adult; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003937:Diagnosis, Differential; D004562:Electrocardiography; D006801:Humans; D008297:Male; D008691:Methadone / Q000008:administration & dosage / Q000009:adverse effects*; D008991:Monitoring, Physiologic; D009294:Narcotics / Q000008:administration & dosage / Q000009:adverse effects*; D019966:Substance-Related Disorders / Q000534:rehabilitation*; D013997:Time Factors; D016171:Torsades de Pointes / Q000139:chemically induced* / Q000175:diagnosis / Q000628:therapy
D009294:Narcotics; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D008691:Methadone