Drug interactions
Carbamazepine + Valproic acid
Severity: Moderate
Carbamazepine and Valproic acid: 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
Carbamazepine induces valproate metabolism and lowers its levels. Valproate can inhibit epoxide hydrolase, raising the active carbamazepine-10,11-epoxide metabolite and causing neurotoxicity despite normal carbamazepine levels. Both effects may disrupt seizure control or tolerability.
What this interaction means in plain words
Carbamazepine and Valproic acid 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.
Carbamazepine belongs to Central Nervous System; Valproic acid belongs to Central Nervous System.
Why it happens
Carbamazepine induces valproate metabolism, while valproate inhibits epoxide hydrolase and may displace carbamazepine from protein binding.
What to do
Monitor valproate and carbamazepine levels and watch for signs of neurotoxicity such as ataxia, diplopia and drowsiness. Adjust doses on 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 Carbamazepine
- Artemether / lumefantrine + Carbamazepine Contraindicated
- Cabotegravir + Carbamazepine Contraindicated
- Carbamazepine + Delamanid Contraindicated
- Carbamazepine + Dienogest / estradiol valerate Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Carbamazepine + Elbasvir / grazoprevir Contraindicated
Other interactions of Valproic acid
- Ertapenem + Valproic acid Contraindicated
- Imipenem / cilastatin / relebactam + Valproic acid Contraindicated
- Imipenem / cilastatin + Valproic acid Contraindicated
- Meropenem / vaborbactam + Valproic acid Contraindicated
- Meropenem + Valproic acid Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Valproic acid Major
Frequently asked questions
Can I take Carbamazepine with Valproic acid?
MediHelp rates the interaction as moderate. Carbamazepine and Valproic acid 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. Carbamazepine induces valproate metabolism and lowers its levels. Valproate can inhibit epoxide hydrolase, raising the active carbamazepine-10,11-epoxide metabolite and causing neurotoxicity despite normal carbamazepine levels. Both effects may disrupt seizure control or tolerability.
How serious is the interaction between Carbamazepine and Valproic acid?
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 valproate and carbamazepine levels and watch for signs of neurotoxicity such as ataxia, diplopia and drowsiness. Adjust doses on clinical response.
What other medicines interact with Carbamazepine?
MediHelp also lists interactions of Carbamazepine with, for example, Artemether / lumefantrine, Cabotegravir, Delamanid. The full list is on the Carbamazepine page.
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