A client is beginning methadone for severe persistent pain and also has hypokalemia and a prescription for another QT-prolonging drug. Which plan is most appropriate?
1Increase methadone every 12 hours until pain improves and start pulse oximetry after each dose increase.
2Begin methadone without reviewing the medication list because QT effects are limited to overdose concentrations.
3Correct electrolytes, review QT drugs, obtain an indicated ECG, titrate slowly, and monitor breathing and sedation.✓ Correct answer
4Use methadone as an as-needed drug and reassess pain after 30 minutes because its effects are brief and predictable.
Explanation
Methadone can cause life-threatening respiratory depression and QT prolongation. Its respiratory-depressant effect can peak later and last longer than its analgesic effect, so rapid dose escalation is unsafe. Hypokalemia and other QT-prolonging drugs increase arrhythmia risk; these factors require correction or review, clinically indicated ECG surveillance, slow titration, and close respiratory assessment. Methadone is not an as-needed analgesic.
Clinical reasoning Methadone has variable pharmacokinetics, delayed respiratory toxicity, and a recognized risk of QT prolongation. Electrolyte abnormalities and interacting drugs compound that risk.
Decision rule Before and during titration, review QT and metabolic interactions, correct potassium and magnesium abnormalities, use ECG monitoring when indicated, and monitor sedation and breathing closely.