methadone mechanism and uses

Methadone is a unique full mu opioid receptor agonist with an inherently long and variable plasma half-life (average, 24 hours) and a shorter analgesic half-life (4—8 hours) during which it has pain-relieving effects. It can be used clinically to treat both opioid use disorder (OUD) and chronic pain, but the regulations and dosing differ for the two indications.

When methadone is used to treat OUD in the United States, it is highly regulated and can be dispensed only through certified methadone-treatment programs; it is typically dosed once daily in this setting because its long plasma half-life can help curb cravings and prevent opioid withdrawal.

In contrast, when methadone is used to treat chronic pain, it is usually dosed every 8 to 12 hours because of its shorter analgesic half-life, and it can be prescribed by any clinician licensed to prescribe controlled substances.

Methadone can be an ideal medication to treat chronic pain because of its long duration of action, low cost, and the fact that it is the only extended-release/long-acting opioid currently available in a liquid formulation. It also blocks the N-methyl-D-aspartate (NMDA) receptor, which has been implicated in the development of neuropathic pain, opioid tolerance, and opioid-induced hyperalgesia.1

Footnotes

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