Drug interactions
Phenobarbital + Tramadol
Severity: Major
Phenobarbital and Tramadol: 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 and tramadol both depress the central nervous system, so concurrent use can cause marked sedation and respiratory depression. Phenobarbital is a strong enzyme inducer and can lower tramadol and O-desmethyltramadol concentrations, which may reduce pain relief. Tramadol can also lower seizure threshold, which complicates use in patients taking anticonvulsants.
What this interaction means in plain words
Phenobarbital and Tramadol 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 and respiratory depression, plus induction of CYP3A4 and CYP2B6 by phenobarbital that increases tramadol clearance.
What to do
Avoid if an alternative exists; otherwise start with low tramadol doses and monitor sedation, respiratory rate and analgesic effect. Adjust therapy if pain control is lost or when phenobarbital is 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 Tramadol
- Isocarboxazid + Tramadol Contraindicated
- Olanzapine / samidorphan + Tramadol Contraindicated
- Phenelzine + Tramadol Contraindicated
- Procarbazine + Tramadol Contraindicated
- Rasagiline + Tramadol Contraindicated
- Safinamide + Tramadol Contraindicated
Frequently asked questions
Can I take Phenobarbital with Tramadol?
MediHelp rates the interaction as major. Phenobarbital and Tramadol 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 and tramadol both depress the central nervous system, so concurrent use can cause marked sedation and respiratory depression. Phenobarbital is a strong enzyme inducer and can lower tramadol and O-desmethyltramadol concentrations, which may reduce pain relief. Tramadol can also lower seizure threshold, which complicates use in patients taking anticonvulsants.
How serious is the interaction between Phenobarbital and Tramadol?
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 if an alternative exists; otherwise start with low tramadol doses and monitor sedation, respiratory rate and analgesic effect. Adjust therapy if pain control is lost or when phenobarbital is stopped.
What other medicines interact with Tramadol?
MediHelp also lists interactions of Tramadol with, for example, Isocarboxazid, Olanzapine / samidorphan, Phenelzine. The full list is on the Tramadol page.
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