Drug interactions
Methadone + Pentazocine
Severity: Major
Methadone and Pentazocine: 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
Pentazocine is a mixed agonist-antagonist that can precipitate withdrawal in patients physically dependent on methadone and may reduce analgesia. In non-dependent patients it can add to sedation.
What this interaction means in plain words
Methadone and Pentazocine 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.
Methadone belongs to Musculoskeletal; Pentazocine belongs to Musculoskeletal.
Why it happens
Partial agonist and antagonist activity at opioid receptors competes with methadone's full agonism.
What to do
Avoid in patients taking methadone regularly. If used, monitor for withdrawal symptoms and inadequate analgesia.
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 Pentazocine
- Calcium / magnesium / potassium / sodium oxybates + Pentazocine Contraindicated
- Olanzapine / samidorphan + Pentazocine Contraindicated
- Pentazocine + Phenelzine Contraindicated
- Pentazocine + Tranylcypromine Contraindicated
- Alfentanil + Pentazocine Major
- Alprazolam + Pentazocine Major
Frequently asked questions
Can I take Methadone with Pentazocine?
MediHelp rates the interaction as major. Methadone and Pentazocine 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. Pentazocine is a mixed agonist-antagonist that can precipitate withdrawal in patients physically dependent on methadone and may reduce analgesia. In non-dependent patients it can add to sedation.
How serious is the interaction between Methadone and Pentazocine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid in patients taking methadone regularly. If used, monitor for withdrawal symptoms and inadequate analgesia.
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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