Drug interactions
Carbamazepine + Methadone
Severity: Major
Carbamazepine and Methadone: major 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
Carbamazepine induces methadone metabolism, substantially lowering methadone concentrations. This can cause opioid withdrawal or loss of analgesia, and toxicity may occur if carbamazepine is stopped.
What this interaction means in plain words
Carbamazepine and Methadone can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Carbamazepine belongs to Central Nervous System; Methadone belongs to Musculoskeletal.
Why it happens
Induction of CYP3A4 and CYP2B6 by carbamazepine increases methadone clearance.
What to do
Monitor for withdrawal and increase the methadone dose as needed. Reduce the dose and monitor for sedation if carbamazepine is withdrawn.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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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 Carbamazepine
- Artemether / lumefantrine + Carbamazepine Contraindicated
- Cabotegravir + Carbamazepine Contraindicated
- Carbamazepine + Delamanid Contraindicated
- Carbamazepine + Dienogest / estradiol valerate Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Carbamazepine + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Carbamazepine with Methadone?
MediHelp rates the interaction as major. Carbamazepine and Methadone can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Carbamazepine induces methadone metabolism, substantially lowering methadone concentrations. This can cause opioid withdrawal or loss of analgesia, and toxicity may occur if carbamazepine is stopped.
How serious is the interaction between Carbamazepine and Methadone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for withdrawal and increase the methadone dose as needed. Reduce the dose and monitor for sedation if carbamazepine is withdrawn.
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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