Drug interactions
Phenobarbital + Regorafenib
Severity: Major
Phenobarbital and Regorafenib: 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 is a strong CYP3A4 inducer and can lower regorafenib plasma concentrations, potentially reducing antitumor efficacy. Exposure to the active metabolite M-5 may rise, with uncertain clinical consequences. Labeling advises avoiding strong inducers.
What this interaction means in plain words
Phenobarbital and Regorafenib 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
Induction of CYP3A4 increases regorafenib metabolism and shifts the balance of active metabolites.
What to do
Avoid concurrent use and choose a non-inducing anticonvulsant where seizure control is needed. If unavoidable, monitor tumor response and toxicity closely.
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 Regorafenib
Frequently asked questions
Can I take Phenobarbital with Regorafenib?
MediHelp rates the interaction as major. Phenobarbital and Regorafenib 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 is a strong CYP3A4 inducer and can lower regorafenib plasma concentrations, potentially reducing antitumor efficacy. Exposure to the active metabolite M-5 may rise, with uncertain clinical consequences. Labeling advises avoiding strong inducers.
How serious is the interaction between Phenobarbital and Regorafenib?
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 concurrent use and choose a non-inducing anticonvulsant where seizure control is needed. If unavoidable, monitor tumor response and toxicity closely.
What other medicines interact with Regorafenib?
MediHelp also lists interactions of Regorafenib with, for example, Apalutamide, Atazanavir, Carbamazepine. The full list is on the Regorafenib page.
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