QT Prolongation and Risk of Death with the Use of Methadone for Chronic Cancer and Noncancer Pain: Myths or Reality?

The use of methadone has been associated with corrected QT (QTc) prolongation. However, conclusions about the dangers of methadone are limited by its dual use for narcotic abuse deterrence. All these observations can deter physicians from prescribing methadone in patients with chronic pain, particularly those with cancer pain. The aim of this review was to evaluate the existing data regarding the relevance of QT changes, the risk factors for QTc prolongation, as well as the risk for cardiac events and mortality, in patients receiving methadone for chronic pain. In total, 15 studies were evaluated. They differed greatly in design (prospective, retrospective), levels of QTc ranges, number of patients included, and methadone doses. Data suggest that the relevance of QTc prolongation induced by methadone seems to be minimal, also considering the range of dosages commonly used in both noncancer and cancer pain. Some risk factors for QTc prolongation have been identified. Information regarding a prior history or prolonged QTc interval, a family history of a prolonged QTc interval, or a family history of sudden, unexplained death is crucial. In this population and at clinical methadone dosages, serious cardiac events have not been described. Low doses of methadone commonly used in most chronic patients may not require QTc monitoring. When a patient is receiving various medications that could potentially prolong QTc, clinicians may consider obtaining a manually measured QTc. Early discussions with patients regarding goals of care, risks, and benefits will help avoid QTc measurements at regular intervals.