Oxcarbazepine

Introduction

Carbamazepine is an anticonvulsant medication used primarily in the treatment of epilepsy. It has been used both alone and as add-on therapy for partial seizures with or without secondary generalization.

Generic Name 藥名	HA Code 藥物代碼	Classification藥物分類
		P1S1S3

Pronunciation

Oxcarbazepine 600mg

Mechanism of Action

Anticonvulsant medication. It is a sodium channel blocker. It binds to sodium channels and suppresses repetitive neuronal firing.

Dosage

1. Epilepsy

Oral	initially 300 mg twice daily increased according to response in steps of up to 600 mg daily at weekly intervals; usual dose rage 0.6 – 2.4 g daily in divided doses.

Administration in children

6 – 18 years	8 – 10 mg/kg daily in 2 divided doses increased according to response in steps of up to 10mg/kg daily at weekly intervals, to a maximum dose of 46 mg/kg daily. Usual maintenance doses in adjunctive therapy around 30mg/kg daily.

Side Effects

Common side effects include:

• Drowsiness, dizziness and headaches
• Gastrointestinal disturbances, such as nausea and vomiting
• The loss of full control of bodily movements (motor coordination impairment)
• Increased risks of hyponatremia and SIADH
• Blood disorders (such as decreased white blood cell or platelet counts)

Serious side effects may include:

• Skin rashes, exfoliative dermatitis, epidermal necrolysis, Stevens-Johnson syndrome, and SLE
• Decreased bone marrow function
• Suicidal thoughts
• Abnormal heart rhythms
• Blurry or double vision, nystagmus
• Male infertility
• Osteoporosis
• Gynecomastia
• Galactorrhea
• Photosensitivity leading to severe sunburns as a result of sun exposure

Pharmacokinetics

Oral bioavailability	Oxcarbazepine is a prodrug which is metabolized to its pharmacologically active metabolite licarbazepine. It has high bioavailability upon oral administration.
Onset of action	The half-life of oxcarbazepine is about 2 hours, whereas licarbazepine has a half-life of 9 hours. The latter provides most of the antiepileptic activity
Metabolism	Licarbazepine is metabolized in the liver
Elimination half-life	Excreted in the urine, with faeces accounting to less than 4%.