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NERVOUS SYSTEM › ANALGESICS › OPIOIDS › Diphenylpropylamine derivatives
methadone, combinations excl. psycholeptics
N02AC52
Forms & Strengths
- Oral Tablet: 5 mg, 10 mg
- Oral Solution: 5 mg/5 mL, 10 mg/5 mL
- Oral Concentrate: 10 mg/mL
- Injectable Solution: 10 mg/mL
Adult Dosing
- Opioid Use Disorder (Detoxification/Maintenance): Initial 20-30 mg daily, titrate by 5-10 mg daily to target 80-120 mg/day
- Chronic Pain: Initial 2.5-5 mg orally every 8-12 hours, titrate cautiously every 3-5 days
Pediatric Dosing
- Safety and effectiveness in pediatric patients under 18 years of age not established for opioid use disorder or chronic pain
Indications
- Management of opioid use disorder (detoxification and maintenance)
- Management of severe chronic pain refractory to alternative options
Mechanism of Action
- Full mu-opioid receptor agonist
- N-methyl-D-aspartate (NMDA) receptor antagonist
- Inhibitor of serotonin and norepinephrine reuptake
Contraindications
- Hypersensitivity to methadone
- Significant respiratory depression
- Acute or severe bronchial asthma in an unmonitored setting
- Known or suspected paralytic ileus
Adverse Reactions
- Respiratory depression
- QT prolongation and Torsades de Pointes
- Constipation, nausea, vomiting
- Sedation, dizziness, somnolence
- Hypotension, syncope
- Androgen deficiency, sexual dysfunction
Drug Interactions
- CYP3A4, CYP2B6, CYP2C19 inducers (e.g., rifampin, carbamazepine, phenytoin) decrease methadone levels, risking withdrawal
- CYP3A4 and CYP2D6 inhibitors (e.g., ketoconazole, macrolides, SSRIs) increase methadone levels, risking toxicity
- QT-prolonging drugs (e.g., antipsychotics, antiarrhythmics) increase risk of serious arrhythmias
- Central nervous system depressants (e.g., alcohol, benzodiazepines) increase risk of profound sedation and respiratory depression
Curated Content: Needs Vetting Before Put to Clinical Use