Drug interactions
Diazepam + Felbamate
Severity: Moderate
Diazepam and Felbamate: 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 inhibits CYP2C19, which is involved in diazepam demethylation, and can raise diazepam or desmethyldiazepam exposure. This may increase sedation, and felbamate's own CNS effects add to this.
What this interaction means in plain words
Diazepam and Felbamate 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.
Diazepam belongs to Musculoskeletal; Felbamate belongs to Central Nervous System.
Why it happens
Felbamate inhibits CYP2C19 mediated metabolism of diazepam.
What to do
Monitor for excessive sedation and ataxia when felbamate is started and reduce the diazepam dose if these occur.
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 Diazepam
Other interactions of Felbamate
- Felbamate + Ulipristal Major
- Amisulpride + Felbamate Moderate
- Amitriptyline + Felbamate Moderate
- Apalutamide + Felbamate Moderate
- Asenapine + Felbamate Moderate
- Bosentan + Felbamate Moderate
Frequently asked questions
Can I take Diazepam with Felbamate?
MediHelp rates the interaction as moderate. Diazepam and Felbamate 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 inhibits CYP2C19, which is involved in diazepam demethylation, and can raise diazepam or desmethyldiazepam exposure. This may increase sedation, and felbamate's own CNS effects add to this.
How serious is the interaction between Diazepam and Felbamate?
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 excessive sedation and ataxia when felbamate is started and reduce the diazepam dose if these occur.
What other medicines interact with Diazepam?
MediHelp also lists interactions of Diazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Alfentanil, Alprazolam. The full list is on the Diazepam page.
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