Prolonged QT interval and methadone: implications for palliative care

Abstract

Purpose of review: To examine the recent literature with regards to methadone, prolongation of the QT interval, torsade de pointes and the implications for palliative care clinicians.

Recent findings: There is a disproportionate number of unexpected deaths seen in patients receiving methadone. Although many of these deaths are likely to be a result of respiratory depression, torsade de pointes may be a contributing factor. Guidelines have been developed to minimize the risk, but these are generally based on expert opinion because of a lack of robust evidence. Routine ECG screening is controversial, but most guidelines advise an ECG in the presence of one or more risk factors for QT interval prolongation.

Summary: The safe use of methadone requires clinicians to be familiar with its pharmacology and to closely monitor patients to avoid an unintentional overdose. As a minimum, clinicians should be aware of the advice regarding prolonged QT in the Summary of Product Characteristics for methadone and the general advice regarding ECG monitoring. These can be given due consideration when balancing the benefits versus the risks of the use of methadone, taking the circumstances of the patient fully into account. Clinicians should also be aware of the potential significance of palpitation, syncope or seizure-like activity in a patient taking methadone.