Drug interactions
Oxycodone + Phenobarbital
Severity: Major
Oxycodone and Phenobarbital: major interaction.
Last updated
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
Phenobarbital adds to opioid CNS and respiratory depression. As a CYP3A4 inducer, it can also lower oxycodone exposure, reducing analgesia and risking withdrawal, with a rebound in oxycodone levels when phenobarbital is stopped.
What this interaction means in plain words
Oxycodone and Phenobarbital 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.
Why it happens
Additive CNS depression plus CYP3A4 induction increasing oxycodone clearance.
What to do
Monitor sedation, respiratory rate and pain control, and titrate oxycodone to effect. Reassess the dose when phenobarbital is started, changed or stopped.
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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Other interactions of Oxycodone
- Alvimopan + Oxycodone Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Oxycodone Contraindicated
- Isocarboxazid + Oxycodone Contraindicated
- Olanzapine / samidorphan + Oxycodone Contraindicated
- Oxycodone + Phenelzine Contraindicated
- Oxycodone + Sodium oxybate Contraindicated
Frequently asked questions
Can I take Oxycodone with Phenobarbital?
MediHelp rates the interaction as major. Oxycodone and Phenobarbital 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. Phenobarbital adds to opioid CNS and respiratory depression. As a CYP3A4 inducer, it can also lower oxycodone exposure, reducing analgesia and risking withdrawal, with a rebound in oxycodone levels when phenobarbital is stopped.
How serious is the interaction between Oxycodone and Phenobarbital?
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 sedation, respiratory rate and pain control, and titrate oxycodone to effect. Reassess the dose when phenobarbital is started, changed or stopped.
What other medicines interact with Oxycodone?
MediHelp also lists interactions of Oxycodone with, for example, Alvimopan, Calcium / magnesium / potassium / sodium oxybates, Isocarboxazid. The full list is on the Oxycodone page.
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