Lamotrigine
Generic Details
Generic Name
Lamotrigine
Other Names
- Lamictal
Drug Class
- Antiepileptic
- Anticonvulsant
Chemical Formula
C9H7Cl2N5
Molecular Weight
256.09 g/mol
Mechanism of Action
- Blocks voltage-sensitive sodium channels, inhibits glutamate release
Indications
- Epilepsy (seizures)
- Bipolar disorder
Common Dosage Forms
- Tablet
- Chewable/dispersible tablet
- Extended-release tablet
Typical Dosage
- 25 mg to 200 mg once or twice daily for epilepsy
- 25 mg to 400 mg once daily for bipolar disorder
Pediatric Dosage
- Dose based on weight and age, typically starting at 0.3-1.2 mg/kg/day
Geriatric Dosage
- Lower initial doses may be required due to decreased renal function
Side Effects
- Headache
- Nausea
- Dizziness
- Blurred vision
- Rash
- Serious skin reactions (e.g., Stevens-Johnson syndrome)
Contraindications
- Hypersensitivity to lamotrigine
Pregnancy Category
- C - Risk cannot be ruled out
Lactation Safety
- Limited data, caution advised
Drug Interactions
- Valproic acid may increase lamotrigine levels
- Carbamazepine may decrease lamotrigine levels
Overdose Symptoms
- Ataxia
- Drowsiness
- Vomiting
- Cardiac conduction delays
Antidote for Overdose
- Activated charcoal, symptomatic treatment
Storage Conditions
- Store at room temperature away from moisture and heat
Pharmacokinetics
- Absorption: Rapid and almost complete
- Distribution: Widely distributed in tissues
- Metabolism: Primarily hepatic, undergoes glucuronidation
- Excretion: Renal, mainly as metabolites
Precautions
- Slow titration to reduce the risk of rash
Warnings
- Risk of serious skin reactions, dose-related risk of aseptic meningitis
Others
- May require dose adjustment in renal/hepatic impairment