Oxycarbazepine

Indications

Oxycarbazepine is used for: Partial seizures

Adult Dose

Oral Partial seizures Adult: As monotherapy or adjunctive therapy: Initially, 600 mg daily in 2 divided doses, may increase if necessary in max increments of 600 mg daily at wkly intervals. Maintenance dose: 600-1,200 mg daily or up to 2,400 mg daily in adjunctive therapy or in refractory patients switched from other antiepileptics.

Child Dose

Oral Partial seizures Child: >6 yr 8-10 mg/kg daily in 2 divided doses, may increase if necessary in increments of 10 mg/kg daily at wkly intervals. Maintenance dose: 30 mg/kg daily in adjunctive therapy. Max: 46 mg/kg/day.

Renal Dose

Renal impairment: CrCl (ml/min) Dosage Recommendation <30 Initially, 300 mg daily, increased at wkly intervals or longer.

Administration

May be taken with or without food.

Contra Indications

Hypersensitivity. Lactation.

Precautions

Patient carrying the HLA-B1502 allele. Avoid abrupt withdrawal. Severe renal and hepatic impairment. Pregnancy. Patient Counselling May impair ability to drive or operate machinery. Monitoring Parameters Monitor seizure frequency, serum Na, symptoms of CNS depression, hypersensitivity reactions, serum levels of concomitant antiepileptic drugs during titration; periodic thyroid function test and CBC.

Pregnancy-Lactation

Interactions

May increase plasma concentrations of other anticonvulsants (e.g. phenobarbital, phenytoin). May decrease plasma concentrations of OC and Ca channel blockers. Decreased plasma concentrations w/ potent inducers of CYP isoenzymes (e.g. carbamazepine, phenytoin, phenobarbital).

Adverse Effects

Side effects of Oxycarbazepine : Hyponatraemia; suicidal behaviour or ideation; neuropsychiatric effects (e.g. impaired cognitive or psychomotor performance, somnolence or fatigue, incoordination); dizziness, somnolence, diplopia, fatigue, nausea, vomiting, ataxia, abnormal vision, abdominal pain, tremor, dyspepsia, abnormal gait, hypothyroidism. Rarely, pancytopenia, agranulocytosis, leucopenia. Potentially Fatal: Stevens-Johnson syndrome, toxic epidermal necrolysis; anaphylaxis, angioedema; Drug Reaction w/ Eosinophilia and Systemic Symptoms (DRESS).

Mechanism of Action

Oxcarbazepine and monohydroxy derivative (MHD) block voltage-sensitive Na channels, stabilising hyperexcited neuronal membranes, inhibiting repetitive firing, and decreasing the propagation of synaptic impulses. These actions are believed to prevent the spread of seizures. Oxcarbazepine and MHD also increase K conductance and modulate the activity of high-voltage activated Ca channels.