Oxcarbazepine

10-keto analogue of CBZ·Psychiatry - Mood Stabilisers

Focal (partial) seizures

Authority requiredPBSMOOD STABTrileptal600 mg tablet+2

Max Dose

2400 mg/day

Half-life

9 h (MHD)

Hyponatremia

HIGH RISK

CYP Inducer

MILD

Rapid Summary

Overview

Structural analogue of Carbamazepine. Designed to bypass the toxic liver-enzyme induction of its predecessor. Has far fewer drug interactions but carries a massively higher risk of severe hyponatremia.

Maximum Dose

Max 2400 mg/day (given in divided doses).

Clinical Focus

Up to 30% of patients develop low sodium (SIADH-like effect). Elderly patients are at extreme risk of hyponatremic seizures and coma.

Bottom Line

Oxcarbazepine is an anticonvulsant related to carbamazepine with fewer drug interactions, but causes clinically significant hyponatraemia more frequently and still requires monitoring.

Formulation & Access

Brand Names

Trileptal

Oral Routes

Tablets (150, 300, 600 mg). Oral suspension.

Prescribing & PBS

Authority Required (PBS).

Indications & Use

Primary

PBSTGA

Focal (partial) seizures.

Off-Label

OFF

Bipolar disorder (maintenance), Trigeminal neuralgia.

Clinical Place

A cleaner, safer alternative to Carbamazepine for focal epilepsy or bipolar disorder, provided the patient's sodium levels remain stable.

Quick reference

Class & Role

10-keto analogue of CBZ — Structural analogue of Carbamazepine.

Route / Formulation

Tablets (150, 300, 600 mg). Oral suspension. (Trileptal)

Usual Dose & Max

Start PO 300 mg BD. Titrate up by 600 mg/day every week. Target 900-2400 mg/day. Max 2400 mg/day (given in divided doses).

Key Indication Doses

Epilepsy / Bipolar Maintenance: Start PO 300 mg BD. Titrate up by 600 mg/day every week. Target 900-2400 mg/day. Renal Impairment: Halve the starting dose (150 mg BD) if eGFR < 30.

Best Uses

Oxcarbazepine is an anticonvulsant related to carbamazepine with fewer drug interactions, but causes clinically significant hyponatraemia more frequently and still requires monitoring.

Avoid / Cautions

Known hypersensitivity to carbamazepine (extreme caution). Pregnancy Category D. Teratogenic (craniofacial defects, heart defects).

Key Risks

Metabolic: Severe hyponatremia (<125 mmol/L). Often asymptomatic until the patient suddenly seizes or becomes comatose. Dermatological: SJS/TEN and DRESS syndrome (High risk in patients with HLA-B*1502 allele, common in Asian populations). Cross-reacts in 30% of patients with a Carbamazepine allergy. Neurological: Dizziness, somnolence, diplopia (double vision).

Key Interactions

Weak inducer of CYP3A4, but strong enough to completely destroy the efficacy of oral contraceptives (OCPs), causing unplanned pregnancy. Must use IUD or barrier. Inhibits CYP2C19. Will significantly raise blood levels of Phenytoin.

Monitoring

Check U&E (sodium) at baseline, 2 weeks, 1 month, 3 months, and if the patient develops lethargy or confusion. Instruct the patient to immediately report any skin rash or mucosal blistering (SJS).

Clinical Pearl

Carbamazepine is a metabolic nightmare because it induces its own metabolism (auto-induction) and destroys the blood levels of almost every other drug the patient takes. Oxcarbazepine does not auto-induce, making blood levels highly stable and polypharmacy much safer.

Access

Authority requiredTrileptal600 mg tablet

Brand: Trileptal
PBS status: Authority required
Formulation: Tablets (150, 300, 600 mg)

Oxcarbazepine

10-keto analogue of CBZ·Psychiatry - Mood Stabilisers

Focal (partial) seizures

Authority requiredPBSMOOD STABTrileptal600 mg tablet+2

Max Dose

2400 mg/day

Half-life

9 h (MHD)

Hyponatremia

HIGH RISK

CYP Inducer

MILD

Rapid Summary

Overview

Maximum Dose

Max 2400 mg/day (given in divided doses).

Clinical Focus

Up to 30% of patients develop low sodium (SIADH-like effect). Elderly patients are at extreme risk of hyponatremic seizures and coma.

Bottom Line

Oxcarbazepine is an anticonvulsant related to carbamazepine with fewer drug interactions, but causes clinically significant hyponatraemia more frequently and still requires monitoring.

Formulation & Access

Brand Names

Trileptal

Oral Routes

Tablets (150, 300, 600 mg). Oral suspension.

Prescribing & PBS

Authority Required (PBS).

Indications & Use

Primary

PBSTGA

Focal (partial) seizures.

Off-Label

OFF

Bipolar disorder (maintenance), Trigeminal neuralgia.

Clinical Place

A cleaner, safer alternative to Carbamazepine for focal epilepsy or bipolar disorder, provided the patient's sodium levels remain stable.

Quick reference

Class & Role

10-keto analogue of CBZ — Structural analogue of Carbamazepine.

Route / Formulation

Tablets (150, 300, 600 mg). Oral suspension. (Trileptal)

Usual Dose & Max

Start PO 300 mg BD. Titrate up by 600 mg/day every week. Target 900-2400 mg/day. Max 2400 mg/day (given in divided doses).

Key Indication Doses

Epilepsy / Bipolar Maintenance: Start PO 300 mg BD. Titrate up by 600 mg/day every week. Target 900-2400 mg/day. Renal Impairment: Halve the starting dose (150 mg BD) if eGFR < 30.

Best Uses

Oxcarbazepine is an anticonvulsant related to carbamazepine with fewer drug interactions, but causes clinically significant hyponatraemia more frequently and still requires monitoring.

Avoid / Cautions

Known hypersensitivity to carbamazepine (extreme caution). Pregnancy Category D. Teratogenic (craniofacial defects, heart defects).

Key Risks

Key Interactions

Monitoring

Check U&E (sodium) at baseline, 2 weeks, 1 month, 3 months, and if the patient develops lethargy or confusion. Instruct the patient to immediately report any skin rash or mucosal blistering (SJS).

Clinical Pearl

Access

Authority requiredTrileptal600 mg tablet

Brand: Trileptal
PBS status: Authority required
Formulation: Tablets (150, 300, 600 mg)