Section 06 · Monograph

Oxcarbazepine

Reviewed Nov 2026FDA label

TrileptalNa+ channel blocker

Indications

Monotherapy or adjunctive therapy for partial-onset seizures in adultsFDA-labeled
Monotherapy for partial-onset seizures in children ages 4–16FDA-labeled
Adjunctive therapy for partial-onset seizures in children ages 2–16FDA-labeled

Blocks voltage-gated Na+ channels, stabilizing hyperexcited neuronal membranes
Pharmacologic activity is largely mediated by its active metabolite, the 10-monohydroxy derivative (MHD/licarbazepine)
Structurally related to carbamazepine but metabolized via a different pathway (reduction rather than epoxidation), which reduces but does not eliminate cross-reactivity

Adjunctive therapy, adults: initiate 600mg/day in 2 divided doses, increase by up to 600mg/day at weekly intervals as needed, usual target dose 1200mg/day
Monotherapy conversion in adults: may titrate to doses up to 2400mg/day

Renal impairment (CrCl <30mL/min): initiate at half the usual starting dose and titrate more slowly

Pediatric dosing is weight-based, typically initiated around 8–10mg/kg/day in 2 divided doses and titrated over about 2 weeks

Approximately 25–30% cross-reactivity for hypersensitivity reactions in patients with a history of carbamazepine hypersensitivity — ask about prior carbamazepine reactions before starting
Moderate induction of CYP3A4/5 reduces efficacy of hormonal contraceptives — alternative or additional contraception recommended
Inhibits CYP2C19, which can increase phenytoin levels at higher oxcarbazepine doses
Additive risk of hyponatremia with other sodium-lowering drugs (e.g., diuretics, SSRIs)

Common: dizziness, somnolence, diplopia, fatigue, nausea, vomiting, ataxia, abnormal vision, headache, nystagmus, tremor, abnormal gait
Clinically significant hyponatremia (sodium <125mmol/L) occurred in about 2.5% of patients in controlled trials, versus no cases on placebo — most common in the first 3 months but can occur later
Anaphylaxis and angioedema
Serious dermatologic reactions and multiorgan hypersensitivity reactions

Serum sodium, particularly during the first several months of treatment, in patients on concurrent sodium-lowering drugs, or if symptoms such as nausea, malaise, headache, confusion, or worsening seizures occur
Signs of hypersensitivity reaction, especially in patients with a history of carbamazepine sensitivity

Limited human pregnancy data; animal studies show developmental toxicity at clinically relevant exposures
Consider enrollment in the North American Antiepileptic Drug (NAAED) Pregnancy Registry
Present in breast milk; weigh benefits of breastfeeding against potential infant exposure