Drug interactions
Primidone + Regorafenib
Severity: Major
Primidone 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
Primidone is metabolized to phenobarbital, which induces CYP3A4 and can lower regorafenib exposure and reduce its efficacy. Levels of the active metabolite M-5 may increase. The combination is best avoided.
What this interaction means in plain words
Primidone 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.
Primidone belongs to Central Nervous System; Regorafenib belongs to Oncology.
Why it happens
Primidone and its metabolite phenobarbital induce CYP3A4, accelerating regorafenib metabolism.
What to do
Avoid the combination and switch to a non-inducing antiseizure drug such as levetiracetam where possible. If it cannot be avoided, monitor 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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Primidone and Regorafenib, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Regorafenib
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Primidone with Regorafenib?
MediHelp rates the interaction as major. Primidone 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. Primidone is metabolized to phenobarbital, which induces CYP3A4 and can lower regorafenib exposure and reduce its efficacy. Levels of the active metabolite M-5 may increase. The combination is best avoided.
How serious is the interaction between Primidone 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 the combination and switch to a non-inducing antiseizure drug such as levetiracetam where possible. If it cannot be avoided, monitor 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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
