Which receptors does methadone act on?

Methadone is primarily known for its roles as both a mu opioid receptor full agonist and an NMDA receptor antagonist. As a mu opioid receptor agonist, methadone is effective in pain relief and is commonly used in the treatment of opioid dependence and addiction due to its ability to mitigate withdrawal symptoms and reduce cravings without producing the intense euphoric highs associated with other opioids.

In addition to its agonistic effects on the mu opioid receptors, methadone's activity as an NMDA receptor antagonist plays a critical role in its pharmacological profile, particularly in managing chronic pain and mitigating the development of tolerance to opioids. This dual mechanism of action sets methadone apart from other opioids, contributing to its unique effectiveness and safety profile in treating patients with opioid use disorder.

The other receptor types mentioned in the incorrect choices do not align with the primary mechanisms of action for methadone. Specifically, while kappa and delta opioid receptors, as well as GABA receptors, are relevant in the context of opioid pharmacology and neurotransmission, these are not the primary pathways through which methadone exerts its therapeutic effects. Methadone's specific interaction with mu opioid and NMDA receptors defines its clinical applications and underpins its use