Drug interactions
Erlotinib + Primidone
Severity: Moderate
Erlotinib and Primidone: moderate 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 and induces CYP3A4, which can reduce erlotinib levels. Loss of efficacy is the main concern.
What this interaction means in plain words
Erlotinib and Primidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Erlotinib belongs to Oncology; Primidone belongs to Central Nervous System.
Why it happens
Primidone and its metabolite phenobarbital induce CYP3A4, accelerating erlotinib clearance.
What to do
Choose a non-inducing anticonvulsant if possible. If not, monitor response and consider raising the erlotinib dose.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Erlotinib and Primidone, 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 Erlotinib
- Amobarbital + Erlotinib Major
- Apalutamide + Erlotinib Major
- Carbamazepine + Erlotinib Major
- Cobicistat + Erlotinib Major
- Darunavir + Erlotinib Major
- Dexlansoprazole + Erlotinib Major
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 Erlotinib with Primidone?
MediHelp rates the interaction as moderate. Erlotinib and Primidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Primidone is metabolized to phenobarbital and induces CYP3A4, which can reduce erlotinib levels. Loss of efficacy is the main concern.
How serious is the interaction between Erlotinib and Primidone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Choose a non-inducing anticonvulsant if possible. If not, monitor response and consider raising the erlotinib dose.
What other medicines interact with Erlotinib?
MediHelp also lists interactions of Erlotinib with, for example, Amobarbital, Apalutamide, Carbamazepine. The full list is on the Erlotinib 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.
