[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.