Class: Phenyltriazine Anticonvulsant
Dosage Forms. Chewable Tablet: 2 mg, 5 mg, 25 mg; Tablet: 25 mg, 100 mg, 150 mg, 200 mg; Extended-Release Tablet: 25 mg, 50 mg, 100 mg, 200 mg, 250 mg, 300 mg
Common FDA Label Indication, Dosing, and Titration.
1. Bipolar I disorder: Adults: 100-400 po daily
2. Partial seizure, adjunct or monotherapy, tonic-clonic seizure: Adults and Children 12 y and over: Immediate Release, 100-500 mg/d in 2 divided doses; Extended Release, 200-600 mg daily; Children 2-12 y: Immediate Release, 1-15 mg/kg/d in 1 or 2 divided doses, max 400 mg/d
1. Migraine prophylaxis: Adults: 50-300 mg po daily
2. Obesity: Adults: 50-400 mg po daily
3. Trigeminal neuralgia: Adults: 200-400 mg po daily
MOA. Lamotrigine is a phenyltriazine derivative unrelated to other marketed antiepileptic drugs. Lamotrigine inhibits voltage-dependent sodium channels, thereby stabilizing neuronal membranes and reducing the release of excitatory neurotransmitters such as glutamate and aspartate.
Drug Characteristics: Lamotrigine
Medication Safety Issues: Lamotrigine
Drug Interactions: Lamotrigine
Adverse Reactions: Lamotrigine
Efficacy Monitoring Parameters. Seizure severity and frequency if taken for seizures. Decrease in manic or depressive symptoms if for bipolar disorder.
Toxicity Monitoring Parameters. Seek medical attention if yellowing of skin or eyes, unusual bruising or bleeding, blistering skin rash, or shortness of breath.
Key Patient Counseling Points. Seek medical attention if rash develops. Slow titration necessary to minimize side effects. Avoid alcohol. Talk to your healthcare provider if you become or plan to become pregnant. Review driving restrictions for patients with seizures. Place ODT formulation on tongue and allow to dissolve.
Clinical Pearls. Rash is more common in children, when quickly titrated and with high starting doses. Rash usually occurs 2-8 wk after start of therapy. Extended-release products are not approved for use in children younger than 13 y. Bipolar patients have an increased risk of suicide during first 24 wk of therapy. Avoid abrupt discontinuation, increases risk of seizures. Medication guide required at dispensing.