Drug interactions
Amobarbital + Methadone
Severity: Major
Amobarbital 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
Barbiturates induce methadone metabolism, which can reduce methadone levels and precipitate withdrawal or loss of analgesia. They also add to CNS and respiratory depression, so effects can be unpredictable, especially if the barbiturate is stopped.
What this interaction means in plain words
Amobarbital 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.
Amobarbital belongs to Central Nervous System; Methadone belongs to Musculoskeletal.
Why it happens
CYP3A4 induction lowers methadone exposure, plus additive CNS depression.
What to do
Monitor for withdrawal symptoms and adjust methadone dose, and watch for oversedation. If the barbiturate is stopped, reassess methadone dose to avoid toxicity.
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 Amobarbital
- Amobarbital + Calcium / magnesium / potassium / sodium oxybates Contraindicated
- Amobarbital + Doravirine Contraindicated
- Amobarbital + Elbasvir / grazoprevir Contraindicated
- Amobarbital + Isavuconazonium Contraindicated
- Amobarbital + Isocarboxazid Contraindicated
- Amobarbital + Lonafarnib Contraindicated
Frequently asked questions
Can I take Amobarbital with Methadone?
MediHelp rates the interaction as major. Amobarbital 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. Barbiturates induce methadone metabolism, which can reduce methadone levels and precipitate withdrawal or loss of analgesia. They also add to CNS and respiratory depression, so effects can be unpredictable, especially if the barbiturate is stopped.
How serious is the interaction between Amobarbital 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 symptoms and adjust methadone dose, and watch for oversedation. If the barbiturate is stopped, reassess methadone dose to avoid toxicity.
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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