Oxcarbazepine
Oxcarbazepine(中文:奧卡西平)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.
藥名[edit]
| Generic Name 藥名 | HA Code 藥物代碼 | Classification藥物分類 |
|---|---|---|
| P1S1S3 |
Pronunciation[edit]
Oxcarbazepine 600mg[edit]
Mechanism of Action[edit]
Anticonvulsant medication. It is a sodium channel blocker. It binds to sodium channels and suppresses repetitive neuronal firing.
Dosage[edit]
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[edit]
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[edit]
| 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%. |
Drug Management[edit]
Monitoring[edit]
- signs of blood, liver, or skin disorders. Seek immediate medical attention if symptoms such as fever, rash, blistering, mouth ulcers, bruising or bleeding develop.
- Patients with heart failure should be weighed regularly to detect fluid retention.
- Patients with pre-existing cardiac conduction disorders should be carefully monitored.
- Hyponatremia (monitor plasma-sodium concentration in patients at risk).
Drug interaction[edit]
Plasma concentrations of the active metabolite of oxcarbazepine may be reduced by strong inducers of cytochrome P450 isoenzymes, such as phenytoin, or phenobarbital. Oxcarbazepine and its metabolite also have the capacity to induce CYP3A4 and CYP3A5 with the possibility of reducing plasma concentrations of drugs such as dihydropyridine calcium-channel blockers, and oral contraceptives.
Caution[edit]
- Avoid abrupt withdrawal
- avoid in patients with cardiac disease
- Genotype test for HLA-B*1502 allele in Han Chinese of Thai origin (avoid Carbamazepine unless no alternative – risk of Stevens-Johnson syndrome in presence of HLA-B*1502 allele);
- may exacerbate absence and myoclonic seizures
- consider vitamin D supplement for immobilized patients or who have inadequate sun exposure or dietary intake of calcium
- susceptibility to glaucoma
Contraindications[edit]
- AV conduction abnormalities
- History of bone-marrow depression
- Acute porphyria
Hepatic impairment[edit]
Metabolism impaired in advanced liver disease. Caution with use.
Renal impairment[edit]
Initial doses of oxcarbazepine for adult patients with a creatinine clearance of less than 30 ml/minute should be 300 mg daily (half the usual starting dose), increase according to response at weekly intervals or longer.
Pregnancy[edit]
Women of child-bearing potential should discuss with a specialist the impact of both epilepsy, and its treatment, on the outcome of pregnancy. There is an increased risk of teratogenicity associated with the use of antiepileptic drug (especially if used during the first trimester)
Breast-feeding[edit]
Use during breast feeding is not recommended.
Warning:
- This medicine may make you sleepy. If this happens, do not drive or use tools or machines
- Do not stop taking this medicine unless your doctor tells you to stop
FAQ[edit]
How should I take the tablet?[edit]
Donepezil tablet and orodispersible tablet should be taken orally at bedtime, or as directed by the doctor. The orodispersible tablet should be placed on the tongue and allowed to disperse before swallowing with or without water. Both formulations can be taken with or without food.
What should I avoid while taking?[edit]
Avoid abruptly discontinue the medication.
What happen if I overdose?[edit]
Contact your primary care doctor. If emergency situation, call 999
What happen if I miss a dose?[edit]
Take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
