Drug interactions
Methadone + Phenelzine
Severity: Contraindicated
Methadone and Phenelzine: contraindicated interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Combining methadone with a nonselective MAO inhibitor risks serotonin syndrome, severe hypotension, hyperthermia and profound CNS depression. Methadone labeling advises against use with MAOIs or within 14 days of stopping them.
What this interaction means in plain words
Methadone and Phenelzine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Methadone belongs to Musculoskeletal; Phenelzine belongs to Central Nervous System.
Why it happens
MAO inhibition plus methadone's serotonergic activity may precipitate serotonin toxicity, plus additive CNS depression.
What to do
Do not coadminister or use within 14 days of stopping phenelzine. Choose a non-serotonergic alternative.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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References
Other interactions of Methadone
- Alvimopan + Methadone Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Methadone Contraindicated
- Droperidol + Methadone Contraindicated
- Ibutilide + Methadone Contraindicated
- Isocarboxazid + Methadone Contraindicated
- Lefamulin + Methadone Contraindicated
Other interactions of Phenelzine
- 5-HTP + Phenelzine Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amoxapine + Phenelzine Contraindicated
- Atomoxetine + Phenelzine Contraindicated
- Benzphetamine + Phenelzine Contraindicated
- Brimonidine + Phenelzine Contraindicated
Frequently asked questions
Can I take Methadone with Phenelzine?
MediHelp rates the interaction as contraindicated. Methadone and Phenelzine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Combining methadone with a nonselective MAO inhibitor risks serotonin syndrome, severe hypotension, hyperthermia and profound CNS depression. Methadone labeling advises against use with MAOIs or within 14 days of stopping them.
How serious is the interaction between Methadone and Phenelzine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not coadminister or use within 14 days of stopping phenelzine. Choose a non-serotonergic alternative.
What other medicines interact with Methadone?
MediHelp also lists interactions of Methadone with, for example, Alvimopan, Calcium / magnesium / potassium / sodium oxybates, Droperidol. The full list is on the Methadone page.
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