Drug interactions
Ethosuximide + Phenobarbital
Severity: Moderate
Ethosuximide and Phenobarbital: 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
Phenobarbital induces hepatic enzymes including CYP3A4 and can lower ethosuximide concentrations, with possible loss of seizure control. Additive sedation may also occur.
What this interaction means in plain words
Ethosuximide and Phenobarbital 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.
Why it happens
Enzyme induction by phenobarbital increasing ethosuximide clearance, plus additive CNS depression.
What to do
Monitor ethosuximide levels and seizure control, and adjust the dose after starting or stopping phenobarbital; watch for sedation.
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 Ethosuximide
- Benzhydrocodone / acetaminophen + Ethosuximide Major
- Buprenorphine long-acting + Ethosuximide Major
- Buprenorphine subdermal implant + Ethosuximide Major
- Buprenorphine transdermal + Ethosuximide Major
- Calcium / magnesium / potassium / sodium oxybates + Ethosuximide Major
- Ethosuximide + Fentanyl intranasal Major
Frequently asked questions
Can I take Ethosuximide with Phenobarbital?
MediHelp rates the interaction as moderate. Ethosuximide and Phenobarbital 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. Phenobarbital induces hepatic enzymes including CYP3A4 and can lower ethosuximide concentrations, with possible loss of seizure control. Additive sedation may also occur.
How serious is the interaction between Ethosuximide and Phenobarbital?
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 ethosuximide levels and seizure control, and adjust the dose after starting or stopping phenobarbital; watch for sedation.
What other medicines interact with Ethosuximide?
MediHelp also lists interactions of Ethosuximide with, for example, Benzhydrocodone / acetaminophen, Buprenorphine long-acting, Buprenorphine subdermal implant. The full list is on the Ethosuximide page.
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