Last reviewed 2026-04-22 · How we verify

Methadone Pill

Methadone is a synthetic opioid agonist that binds to mu opioid receptors in the central nervous system to produce analgesia and reduce withdrawal symptoms.

Methadone is a synthetic opioid agonist that binds to mu opioid receptors in the central nervous system to produce analgesia and reduce withdrawal symptoms. Used for Opioid use disorder maintenance treatment, Chronic pain management in opioid-tolerant patients.

At a glance

Mechanism of action

Methadone acts as a full agonist at mu opioid receptors, producing effects similar to morphine but with a longer half-life (24-36 hours), which allows for once-daily dosing. It is primarily used in opioid use disorder treatment to prevent withdrawal symptoms and reduce cravings, and secondarily for chronic pain management. The extended duration of action makes it particularly suitable for maintenance therapy in opioid addiction.

Approved indications

• Opioid use disorder maintenance treatment
• Chronic pain management
• Opioid withdrawal prevention

Common side effects

• Constipation
• Sweating
• Sedation
• Nausea
• Respiratory depression
• QT prolongation

Key clinical trials

• Acetazolamide in Central Sleep Apnea Patients Using Medication for Opioid Use Disorder (PHASE2)
• PO Methadone Ortho Outpatient (PHASE3)
• Intensive Models of HCV Care for Injection Drug Users (NA)
• Ibuprofen to Decrease Opioid Use and Post-operative Pain Following Unilateral Inguinal Herniorrhaphy (PHASE3)
• Methadone and Medication Abortion (PHASE4)
• Pharmacotherapy & CM for Opioid and Cocaine Dependence (PHASE1, PHASE2)
• Smoking Cessation Treatment for Methadone Maintenance Patients (PHASE4)
• Evaluating a Novel Medication Device for Methadone Dosing (NA)

Primary sources

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