Drug interactions
Lamotrigine + Primidone
Severity: Moderate
Lamotrigine 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, partly metabolized to phenobarbital, lowers lamotrigine levels and may reduce seizure control. Withdrawal of primidone can lead to increased lamotrigine concentrations.
What this interaction means in plain words
Lamotrigine 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.
Lamotrigine belongs to Central Nervous System; Primidone belongs to Central Nervous System.
Why it happens
Primidone and its phenobarbital metabolite induce lamotrigine glucuronidation.
What to do
Follow the enzyme-inducer lamotrigine dosing schedule and monitor seizure control. Lower the lamotrigine dose if 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 Lamotrigine
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 Lamotrigine with Primidone?
MediHelp rates the interaction as moderate. Lamotrigine 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, partly metabolized to phenobarbital, lowers lamotrigine levels and may reduce seizure control. Withdrawal of primidone can lead to increased lamotrigine concentrations.
How serious is the interaction between Lamotrigine 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: Follow the enzyme-inducer lamotrigine dosing schedule and monitor seizure control. Lower the lamotrigine dose if primidone is stopped.
What other medicines interact with Lamotrigine?
MediHelp also lists interactions of Lamotrigine with, for example, Desogestrel-ethinyl estradiol, Divalproex, Dofetilide. The full list is on the Lamotrigine page.
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