Dear Editor:In the January 2010 issue, Reddy et al. describe the effect of low-dose oral methadone on the rate corrected (QTc) interval in a palliative care population. The safety of low-dose methadone is an important question to evaluate in this population because this medication can be an excellent palliative tool but can also prolong the QTc interval, leading to torsades de pointes, ventricular fibrillation, and sudden death. As a result, one must weigh the palliative benefits of methadone with the risk of arrhythmia and its sequelae. The authors measured QTc at baseline before initiating low-dose methadone and then subsequently at 2,4, and 8 weeks. They did not demonstrate any significant QTc prolongation, and in fact measured a mean reduction in QTc of 50 milliseconds at 4 and 8 weeks. While on the surface these results would indicate that methadone does not prolong QTc at low doses, several study design features require further scrutiny.
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