Drug interactions
Oxymorphone + Phenobarbital
Severity: Major
Oxymorphone 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 taken with oxymorphone produces additive CNS and respiratory depression. Phenobarbital is also an enzyme inducer, but because oxymorphone is cleared by glucuronidation, the pharmacodynamic effect is the main concern.
What this interaction means in plain words
Oxymorphone 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 via opioid agonism and enhanced GABA-A activity.
What to do
Use the lowest effective doses and monitor for sedation and respiratory depression; consider a lower oxymorphone starting dose.
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 Oxymorphone
- Alvimopan + Oxymorphone Contraindicated
- Ethanol + Oxymorphone Contraindicated
- Isocarboxazid + Oxymorphone Contraindicated
- Olanzapine / samidorphan + Oxymorphone Contraindicated
- Oxymorphone + Phenelzine Contraindicated
- Oxymorphone + Selegiline transdermal Contraindicated
Frequently asked questions
Can I take Oxymorphone with Phenobarbital?
MediHelp rates the interaction as major. Oxymorphone 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 taken with oxymorphone produces additive CNS and respiratory depression. Phenobarbital is also an enzyme inducer, but because oxymorphone is cleared by glucuronidation, the pharmacodynamic effect is the main concern.
How serious is the interaction between Oxymorphone 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: Use the lowest effective doses and monitor for sedation and respiratory depression; consider a lower oxymorphone starting dose.
What other medicines interact with Oxymorphone?
MediHelp also lists interactions of Oxymorphone with, for example, Alvimopan, Ethanol, Isocarboxazid. The full list is on the Oxymorphone page.
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