Drug interactions
Primidone + Verapamil
Severity: Moderate
Primidone and Verapamil: 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, partly metabolized to phenobarbital, can reduce verapamil exposure and diminish its therapeutic effect. Loss of blood pressure or rate control may occur.
What this interaction means in plain words
Primidone and Verapamil 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 belongs to Central Nervous System; Verapamil belongs to Cardiovascular.
Why it happens
Primidone and its phenobarbital metabolite induce CYP3A4, increasing verapamil metabolism.
What to do
Monitor heart rate and blood pressure and raise the verapamil dose if needed. Reduce it again when primidone is stopped.
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?
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Other interactions of Verapamil
- Dofetilide + Verapamil Contraindicated
- Flibanserin + Verapamil Contraindicated
- Lomitapide + Verapamil Contraindicated
- Lonafarnib + Verapamil Contraindicated
- Pimozide + Verapamil Contraindicated
- Acebutolol + Verapamil 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 Primidone with Verapamil?
MediHelp rates the interaction as moderate. Primidone and Verapamil 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, partly metabolized to phenobarbital, can reduce verapamil exposure and diminish its therapeutic effect. Loss of blood pressure or rate control may occur.
How serious is the interaction between Primidone and Verapamil?
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 heart rate and blood pressure and raise the verapamil dose if needed. Reduce it again when primidone is stopped.
What other medicines interact with Verapamil?
MediHelp also lists interactions of Verapamil with, for example, Dofetilide, Flibanserin, Lomitapide. The full list is on the Verapamil page.
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