Oxcarbazepine (10,11-dihydro-10-oxo-5H-dibenz[b,f]azepine-5-carboxamide) is a 10-keto analogue of
carbamazepine with
anticonvulsant activity. In newly diagnosed adult patients,
oxcarbazepine monotherapy is as effective as
phenytoin and vaiproic
acid at reducing generalised tonic-clonic and partial seizure frequency. Furthermore,
oxcarbazepine 2400 mg/day as monotherapy has also proved effective in the treatment of refractory
partial seizures in adult patients.
Oxcarbazepine 600, 1200 and 2400 mg/day as adjunctive
therapy significantly reduced seizure frequency compared with placebo in 692 patients with refractory
partial seizures. The efficacy of
oxcarbazepine monotherapy is similar to that of
phenytoin in the treatment of children and adolescents with newly diagnosed partial or generalised
tonic-clonic seizures. Additionally, adjunctive
therapy with
oxcarbazepine was significantly more effective than placebo at reducing seizure frequency in children and adolescents with refractory
partial seizures. The most commonly reported adverse events associated with
oxcarbazepine monotherapy and/or adjunctive
therapy in adults and/or children are
somnolence,
dizziness,
headache,
nausea and
vomiting.
Oxcarbazepine monotherapy is better tolerated than
phenytoin (in both adults and children) and
valproic acid (in adults), and although 75 to 90% of adult patients in 5 recent monotherapy studies reported adverse events while receiving
oxcarbazepine, <8% withdrew from treatment because of them. Acute hyponatraemia, although usually asymptomatic, develops in 2.7% of patients treated with
oxcarbazepine. Adverse events most likely to resolve upon switching to
oxcarbazepine therapy from treatment with
carbamazepine are undetermined skin reactions (rashes,
pruritus,
eczema),
allergic reactions and a combination of malaise,
dizziness and
headache. Although
oxcarbazepine does have a clinically significant interaction with some drugs (e.g.
phenytoin and
oral contraceptives), it has a lower propensity for interactions than older
antiepileptic drugs (AEDs) because its major metabolic pathway is mediated by noninducible
enzymes.
CONCLUSION:
Oxcarbazepine as monotherapy is a viable alternative to established AEDs in the treatment of partial and generalised
tonic-clonic seizures in adults and children. Furthermore, it is also effective as adjunctive
therapy in the treatment of refractory
partial seizures in both age groups. In addition, the
drug is tolerated better than the older, established AEDs, and has a lower potential for drug interactions. These attributes make
oxcarbazepine an effective component in the initial treatment of newly diagnosed partial and generalised
tonic-clonic seizures, and also as an adjunct for medically intractable
partial seizures in both adults and children.