GasGasGas - The FRCA Primary Exam Podcast GasGasGas - Methadone for the FRCA Primary
May 15, 2025
Dive into the multifaceted world of methadone in this session! Discover its unique pharmacodynamics and receptor activities beyond opioid dependency. Learn about its clinical applications in pain management, including cancer care. The podcast covers practical dosing strategies, potential side effects like QT prolongation, and alternatives for weaning off methadone. Unravel the complexity of its pharmacokinetics, with insights into metabolism and clearance, all while gaining valuable knowledge for the medical field.
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Methadone Basics And Opiate Receptor Action
- Methadone is a synthetic opioid and an enantiomeric mix with R-methadone as the active form.
- Opiate receptors are GPCRs that open K+ channels, close Ca2+ channels and reduce cAMP when agonised.
Non-Opioid Actions Expand Methadone Effects
- Methadone also antagonises NMDA receptors and binds serotonergic 5-HT2A receptors.
- These additional actions explain analgesic and serotonergic effects beyond mu-opioid agonism.
Avoid Serotonin Syndrome With Methadone Combos
- Watch for serotonin syndrome when combining methadone with other serotonergic drugs.
- Recognise agitation, flushing, hyperreflexia and myoclonus as key features.