Drug interactions
Pirfenidone + Primidone
Severity: Major
Pirfenidone and Primidone: 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, an enzyme inducer, and may reduce pirfenidone concentrations and its therapeutic effect. The effect is inferred from pirfenidone's CYP1A2 metabolism.
What this interaction means in plain words
Pirfenidone and Primidone 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.
Pirfenidone belongs to Miscellaneous; Primidone belongs to Central Nervous System.
Why it happens
Induction of hepatic enzymes, including CYP1A2, increases pirfenidone clearance.
What to do
Avoid concurrent use where possible and select a non-inducing anticonvulsant; if unavoidable, monitor lung function and clinical response.
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 Pirfenidone
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 Pirfenidone with Primidone?
MediHelp rates the interaction as major. Pirfenidone and Primidone 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, an enzyme inducer, and may reduce pirfenidone concentrations and its therapeutic effect. The effect is inferred from pirfenidone's CYP1A2 metabolism.
How serious is the interaction between Pirfenidone and Primidone?
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 where possible and select a non-inducing anticonvulsant; if unavoidable, monitor lung function and clinical response.
What other medicines interact with Pirfenidone?
MediHelp also lists interactions of Pirfenidone with, for example, Carbamazepine, Ciprofloxacin, Fluvoxamine. The full list is on the Pirfenidone page.
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