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[Pharmacology](https://durgical.com/en/pharmacology/) · [Antiseizure medicines](https://durgical.com/en/pharmacology/classes/antiseizure-medicines/)

# Oxcarbazepine

A relative of carbamazepine for focal seizures. Its active metabolite blocks sodium channels; low blood sodium is its typical problem.

Updated 2026-11-01

- Class: [Antiseizure medicines](https://durgical.com/en/pharmacology/classes/antiseizure-medicines/)
- Ion channel: Voltage-gated sodium channel (Nav)
- ATC code: N03AF02

⇅**Voltage-gated sodium channel (Nav)**Oxcarbazepine

ⓘ The figure shows carbamazepine, a close relative that occupies the same site, bound to human Nav1.7 (SCN9A); no structure with oxcarbazepine or its metabolite is available.

**Target in 3D:** Voltage-gated sodium channel (Nav). PDB structure 8S9C (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/8S9C) · Drag to rotate · pinch to zoom

## Mechanism of action

Oxcarbazepine is quickly reduced to its 10-monohydroxy metabolite (MHD), which does most of the work. Both block voltage-gated sodium channels, stabilizing hyperexcited membranes, inhibiting repetitive firing and reducing the spread of synaptic impulses.

- Reduced to the active metabolite MHD
- MHD blocks voltage-gated sodium channels
- Repetitive neuronal firing is inhibited
- Focal seizures do not spread

## Pharmacokinetics

**Absorption**
Absorbed by mouth

**Metabolism**
Rapidly reduced in the liver to the active metabolite MHD; strong CYP3A4 or UGT inducers lower its levels

**Elimination**
Mainly kidneys; MHD half-life lengthens in severe kidney disease

**Half-life**
About 2 hours for oxcarbazepine and about 9 hours for MHD

## Indications

- Focal (partial-onset) seizures, alone or as add-on [Epilepsy and seizures →](https://durgical.com/en/conditions/epilepsy-and-seizures/)

## Adverse effects

### Common

- Dizziness and sleepiness
- Double vision and abnormal vision
- Nausea and vomiting
- Unsteadiness, tremor and abnormal gait
- Fatigue and headache

### Serious (rare, important)

- Clinically significant hyponatraemia
- Stevens-Johnson syndrome and toxic epidermal necrolysis (HLA-B*1502 risk)
- Cross-hypersensitivity with carbamazepine
- DRESS (multi-organ hypersensitivity)
- Suicidal thoughts

## Contraindications

- Hypersensitivity to oxcarbazepine or to eslicarbazepine acetate

## Key interactions

**Hormonal contraceptives**
Less contraceptive effect

**Strong CYP3A4 or UGT inducers (carbamazepine, phenytoin, phenobarbital)**
Lower MHD levels

**Other drugs that lower sodium, such as those causing inappropriate ADH secretion**
More hyponatraemia

## What is monitored

- Serum sodium, especially in the first months and with other sodium-lowering drugs
- HLA-B*1502 in people with ancestry from at-risk Asian populations
- Skin and signs of hypersensitivity
- Mood and suicidal thoughts

## Administration and safety

- Given by mouth as tablets or suspension
- Immediate- and extended-release forms are not interchangeable without care
- Withdrawn gradually: stopping suddenly can trigger seizures

## Nursing care

- Ask about previous reactions to carbamazepine
- Watch for headache, confusion, nausea or more seizures that may signal low sodium
- Teach to report rash or fever
- Remind that hormonal contraception may fail

## Pregnancy and breastfeeding

MHD levels may fall gradually during pregnancy and recover after delivery, so seizure control is followed closely.

## Memory aid

Oxcarbazepine: «Ox drinks the salt» – carbamazepine's cousin whose typical problem is low sodium.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the active form of oxcarbazepine?

Its 10-monohydroxy metabolite (MHD), which blocks voltage-gated sodium channels and has a longer half-life than the parent drug.

## Which electrolyte must be checked during oxcarbazepine treatment?

Sodium: clinically significant hyponatraemia can develop.

## Can a patient who had a hypersensitivity reaction to carbamazepine safely switch to oxcarbazepine?

Not without caution: cross-hypersensitivity occurs, and oxcarbazepine is stopped at once if signs appear.

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## Related drugs

- [Carbamazepine](https://durgical.com/en/pharmacology/carbamazepine/)
- [Lamotrigine](https://durgical.com/en/pharmacology/lamotrigine/)

## Related conditions

- [Epilepsy and seizures](https://durgical.com/en/conditions/epilepsy-and-seizures/)

[← Back to the class: Antiseizure medicines](https://durgical.com/en/pharmacology/classes/antiseizure-medicines/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Oxcarbazepine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a601245.html) (MedlinePlus (U.S. National Library of Medicine), 2024); [DailyMed - OXCARBAZEPINE tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8841174a-9f4b-424f-a50d-01478f2aeb29) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N03AF02) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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