Drug interactions
Phenytoin + Vigabatrin
Severity: Moderate
Phenytoin and Vigabatrin: 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
Vigabatrin can lower plasma phenytoin concentrations by a modest amount in some patients. This may reduce seizure control if the phenytoin dose is not adjusted.
What this interaction means in plain words
Phenytoin and Vigabatrin 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.
Phenytoin belongs to Central Nervous System; Vigabatrin belongs to Central Nervous System.
Why it happens
The mechanism is not established; a possible effect on phenytoin metabolism has been suggested.
What to do
Monitor phenytoin levels after vigabatrin is started and adjust the dose according to levels and seizure control.
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 Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Vigabatrin
- Amisulpride + Vigabatrin Moderate
- Asenapine transdermal + Vigabatrin Moderate
- Asenapine + Vigabatrin Moderate
- Avapritinib + Vigabatrin Moderate
- Benzhydrocodone / acetaminophen + Vigabatrin Moderate
- Brexanolone + Vigabatrin Moderate
Frequently asked questions
Can I take Phenytoin with Vigabatrin?
MediHelp rates the interaction as moderate. Phenytoin and Vigabatrin 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. Vigabatrin can lower plasma phenytoin concentrations by a modest amount in some patients. This may reduce seizure control if the phenytoin dose is not adjusted.
How serious is the interaction between Phenytoin and Vigabatrin?
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 phenytoin levels after vigabatrin is started and adjust the dose according to levels and seizure control.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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