Drug interactions
Oxybutynin + Primidone
Severity: Moderate
Oxybutynin 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, which induces CYP3A4 and may lower oxybutynin exposure. Additive sedation and cognitive effects may also occur.
What this interaction means in plain words
Oxybutynin 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.
Oxybutynin belongs to Genitourinary; Primidone belongs to Central Nervous System.
Why it happens
CYP3A4 induction by primidone and its metabolite phenobarbital increases oxybutynin metabolism, plus additive CNS depression.
What to do
Monitor for reduced bladder symptom control and for excess sedation; adjust oxybutynin dose according to response.
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 Oxybutynin 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 14 days on the web. No card needed.
Other interactions of Oxybutynin
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 Oxybutynin with Primidone?
MediHelp rates the interaction as moderate. Oxybutynin 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, which induces CYP3A4 and may lower oxybutynin exposure. Additive sedation and cognitive effects may also occur.
How serious is the interaction between Oxybutynin 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: Monitor for reduced bladder symptom control and for excess sedation; adjust oxybutynin dose according to response.
What other medicines interact with Oxybutynin?
MediHelp also lists interactions of Oxybutynin with, for example, Bethanechol, Clozapine, Potassium chloride. The full list is on the Oxybutynin 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.
