Drug interactions
Methadone + Olanzapine / samidorphan
Severity: Contraindicated
Methadone and Olanzapine / samidorphan: 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
Samidorphan is an opioid antagonist that can precipitate acute withdrawal in methadone-dependent patients and blunt the effects of methadone. This can cause severe withdrawal and loss of opioid maintenance.
What this interaction means in plain words
Methadone and Olanzapine / samidorphan 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.
Why it happens
Pharmacodynamic antagonism at opioid receptors by samidorphan.
What to do
Do not use in patients on methadone; ensure the labeled opioid-free interval before starting. Choose an alternative antipsychotic.
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
Frequently asked questions
Can I take Methadone with Olanzapine / samidorphan?
MediHelp rates the interaction as contraindicated. Methadone and Olanzapine / samidorphan 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. Samidorphan is an opioid antagonist that can precipitate acute withdrawal in methadone-dependent patients and blunt the effects of methadone. This can cause severe withdrawal and loss of opioid maintenance.
How serious is the interaction between Methadone and Olanzapine / samidorphan?
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 use in patients on methadone; ensure the labeled opioid-free interval before starting. Choose an alternative antipsychotic.
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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