A patient on chronic high-dose morphine for metastatic bone pain develops myoclonus and hyperalgesia. The physician considers opioid rotation. Which opioid is preferred in renal impairment and has NMDA receptor antagonist properties that may help in this setting?

• A Fentanyl
• B Oxycodone
• C Hydromorphone
• D Methadone ✓

Explanation

Methadone is unique among opioids as it also acts as an NMDA receptor antagonist. This property makes it useful in opioid-induced hyperalgesia and neuropathic pain. It is metabolized hepatically with no active metabolites, making it safer in renal impairment than morphine. Fentanyl also lacks active metabolites but has no NMDA antagonist activity. Methadone's dual mechanism addresses both the hyperalgesia and renal concerns.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.