Generic
Carbamazepine
19 brands available in the market
At a glance
Carbamazepine is an antiepileptic medication used in the treatment of partial and secondary generalized tonic-clonic seizures, primary generalized tonic-clonic seizures, trigeminal neuralgia, and prophylaxis of bipolar disorder. It suppresses abnormal nerve cell activity in the brain to control seizures and pain.
Description
Carbamazepine is an anticonvulsant that depresses activity in the nucleus ventralis of the thalamus, reduces synaptic propagation of excitatory impulses, and decreases neural discharge by limiting Na⁺ ion influx across cell membranes. It stimulates the release of antidiuretic hormone (ADH) and potentiates its action in promoting water reabsorption.
Carbamazepine is indicated for partial and secondary generalized tonic-clonic seizures, primary generalized tonic-clonic seizures, trigeminal neuralgia, and prophylaxis of bipolar disorder. It is not effective in petit mal seizures.
Indications
- Partial and secondary generalized tonic-clonic seizures
- Primary generalized tonic-clonic seizures
- Trigeminal neuralgia
- Prophylaxis of bipolar disorder
- Diabetic neuropathy (off-label)
Therapeutic class
Primary anti-epileptic drugs
Pharmacological class
Anticonvulsant / Mood Stabilizer
Pharmacology
Carbamazepine depresses activity in the nucleus ventralis of the thalamus, reduces synaptic propagation of excitatory impulses, and decreases neural discharge by limiting Na⁺ ion influx across cell membranes. It stimulates ADH release and potentiates its action in promoting water reabsorption.
Mechanism of action
Carbamazepine stabilizes neuronal membranes by blocking sodium channels, reducing the spread of abnormal electrical discharges in the brain and preventing seizures. In trigeminal neuralgia, it reduces pain signal transmission in the brainstem.
Dosage
Adults & children >12 years (Epilepsy): Initial 200 mg twice daily (tablets/XR) OR 1 teaspoon q.i.d. (suspension) = 400 mg/day. Increase by 200 mg/day weekly. Maintenance: 800-1200 mg/day. Max: 1600 mg/day (rare).
Trigeminal Neuralgia: Initial 100-200 mg twice daily; increase gradually. Maintenance: 400-800 mg/day (divided doses). Max: 1200 mg/day. Attempt to reduce to minimum effective dose every 3 months.
Bipolar Disorder Prophylaxis: Initial 400 mg/day (divided doses); increase gradually. Maintenance: 400-600 mg/day (divided doses). Max: 1600 mg/day.
Children (6-12 years): Initial 100 mg twice daily OR 1/2 teaspoon q.i.d. (200 mg/day); increase by 100 mg/day weekly; max 1000 mg/day; maintenance 400-800 mg/day.
Children (<6 years): Initial 10-20 mg/kg/day (divided doses); increase weekly; max 35 mg/kg/day.
Children (12-15 years): Max 1000 mg/day; >15 years: max 1200 mg/day.
Renal/Hepatic impairment: Limited information; caution required.
Administration
May be taken with or without food, preferably at a fixed time each day. Swallow tablets whole; do not chew, crush, or break. Shake suspension well before use.
Missed dose
If you miss a dose, take it as soon as you remember. Skip the missed dose if it is almost time for your next dose. Do not double the dose.
Side effects
Common side effects (especially during initial therapy): Dizziness, drowsiness, ataxia (loss of balance), nausea, vomiting, dry mouth, abdominal pain, anorexia, blurred vision, slurred speech, constipation, fatigue, itching.
Serious (rare): Aplastic anemia, agranulocytosis (hematological), Stevens-Johnson syndrome, toxic epidermal necrolysis (skin), leukopenia, proteinuria, bradycardia, heart failure, hypotension, hepatic problems.
May cause increased sensitivity to sun; use sunscreen or protective clothing when outdoors for prolonged periods.
Precautions & warnings
- May cause dizziness and drowsiness; exercise caution when driving or operating machinery.
- If rash, skin peeling, itching, or other unexplained skin reaction occurs, inform your doctor immediately (risk of serious skin reactions).
- If unexplained itching, yellowing of skin/eyes, dark urine, nausea, vomiting, abdominal pain, loss of appetite, or flu-like symptoms occur, inform your doctor (signs of liver problems).
- Do not stop suddenly (taper gradually under medical supervision).
- Hormonal contraceptives may be ineffective; use contraceptives containing at least 50 mcg estrogen or non-hormonal methods.
- Caution in mixed seizures including absence seizures, elderly, heart disease, kidney/liver disease, psychotic illness, glaucoma, history of drug-induced blood disorders, previous carbamazepine allergy/side effects.
Contraindications
- Hypersensitivity to carbamazepine or any ingredient
- Bone marrow depression
- Porphyria
- Atrioventricular block (heart conduction problems)
- Allergy to tricyclic antidepressants
- MAOI antidepressant use within the last 14 days
- Pregnancy
Drug interactions
- CYP3A4 inhibitors (cimetidine, erythromycin, ketoconazole): Increase carbamazepine plasma levels.
- CYP3A4 inducers (phenytoin, phenobarbital, rifampin, cisplatin): Decrease carbamazepine plasma levels.
- Lithium: Increased risk of neurotoxic side effects.
- Hormonal contraceptives: Reduced efficacy; breakthrough bleeding may occur.
- Loxapine, quetiapine, primidone, progabide, valproic acid, valpromide: Increase active metabolite carbamazepine-10,11-epoxide levels.
- Aripiprazole, tacrolimus, temsirolimus, lapatinib: Plasma levels may be reduced.
- Isoniazid: Increased risk of hepatotoxicity.
- Diuretics (hydrochlorothiazide, furosemide): Risk of symptomatic hyponatremia.
- Nefazodone (MAOI): Decreased serum concentrations; toxic reactions (potentially fatal).
Food interactions
Alcohol may cause excessive drowsiness; avoid alcohol consumption.
Use in pregnancy
Unsafe during pregnancy (Category D). Definite evidence of risk to the developing baby. May be used in life-threatening situations if benefits outweigh risks. Advise pregnant women of potential risk to the fetus. Use effective contraception during treatment.
Pregnancy Category: D — always consult a doctor before taking during pregnancy.
Use in lactation
Safe during breastfeeding (if prescribed). Human studies suggest the drug does not pass into breast milk in significant amounts and is not harmful to the baby. However, carbamazepine and its epoxide metabolite are transferred to breast milk; caution advised.
Pediatric use
6-12 years: Initial 100 mg twice daily; max 1000 mg/day; maintenance 400-800 mg/day.
12-15 years: Max 1000 mg/day.
>15 years: Max 1200 mg/day.
Geriatric use
Elderly patients require caution (start with lower doses, titrate slowly).
Renal / hepatic impairment
Limited information available on use in renal and hepatic impairment; caution required.
Overdose effects
Overdose symptoms: Dizziness, drowsiness, ataxia, nausea, vomiting, seizures, coma, respiratory depression, hypotension, tachycardia, urinary retention. Treatment: Gastric lavage, activated charcoal, supportive care. Consult your doctor immediately if overdose is suspected.
Storage conditions
Store below 30°C, away from light and moisture. Keep out of reach of children.
Chemical structure
Carbamazepine (Iminostilbene Derivative)