Drug interactions
Felbamate + Phenobarbitone
Severity: Moderate
Felbamate and Phenobarbitone: 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
Felbamate raises phenobarbital concentrations, which may cause sedation, ataxia, and cognitive slowing. Phenobarbital in turn can lower felbamate concentrations and reduce seizure control.
What this interaction means in plain words
Felbamate and Phenobarbitone 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.
Felbamate belongs to Central Nervous System; Phenobarbitone belongs to Central Nervous System.
Why it happens
Felbamate inhibits CYP2C19-mediated phenobarbital metabolism, while phenobarbital induces enzymes that increase felbamate clearance.
What to do
Monitor phenobarbital serum levels and consider reducing its dose when felbamate is started. Watch for loss of seizure control and adjust felbamate according to clinical 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?
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Other interactions of Felbamate
- Felbamate + Ulipristal Major
- Amisulpride + Felbamate Moderate
- Amitriptyline + Felbamate Moderate
- Apalutamide + Felbamate Moderate
- Asenapine + Felbamate Moderate
- Bosentan + Felbamate Moderate
Other interactions of Phenobarbitone
- Cabotegravir + Phenobarbitone Contraindicated
- Doravirine + Phenobarbitone Contraindicated
- Isavuconazole + Phenobarbitone Contraindicated
- Darolutamide + Phenobarbitone Major
- Finerenone + Phenobarbitone Major
- Ivacaftor + Phenobarbitone Major
Frequently asked questions
Can I take Felbamate with Phenobarbitone?
MediHelp rates the interaction as moderate. Felbamate and Phenobarbitone 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. Felbamate raises phenobarbital concentrations, which may cause sedation, ataxia, and cognitive slowing. Phenobarbital in turn can lower felbamate concentrations and reduce seizure control.
How serious is the interaction between Felbamate and Phenobarbitone?
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 phenobarbital serum levels and consider reducing its dose when felbamate is started. Watch for loss of seizure control and adjust felbamate according to clinical response.
What other medicines interact with Felbamate?
MediHelp also lists interactions of Felbamate with, for example, Ulipristal, Amisulpride, Amitriptyline. The full list is on the Felbamate page.
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