DRUG | SUPPLIED | DOSE | COMMENTS |
---|---|---|---|
LAMOTRIGINE (Paeds) (Lamictal) Mechanism of action: Anticonvulsant. Lamotrigine is a member of the sodium channel blocking class of antiepileptic drugs and suppresses the release of glutamate and aspartate, two of the dominant excitatory neurotransmitters in the CNS. Ref: 32, 44, 83, 94, 95, 158 Last update: 2023-01-12 |
tablet: 25 mg,100 mg chewable/dispersible tablet: 5 mg (Also available but not stocked at BCCH: 150 mg tablet; 2mg chewable/dispersible tablet |
Seizures: Children 2-12 yrs (or <50 kg): Wk 1 & 2: 0.15 mg/kg/dose PO BID Wk 3 & 4: 0.3 mg/kg/dose PO BID Increment: 0.3 mg/kg/dose PO BID every 7-14 days Maintenance: 2.3-3.8 mg/kg/dose PO BID (4.5-7.5 mg/kg/24 hr) Maximum: 7.5 mg/kg/dose PO BID or 200 mg/dose PO BID With valproic acid: Wk 1 & 2: 0.08 mg/kg/dose PO BID Wk 3 & 4: 0.15 mg/kg/dose PO BID Increment: 0.15 mg/kg/dose PO BID every 7-14 days Maintenance: 0.5-2.5 mg/kg/dose PO BID Maximum: 2.5 mg/kg/dose PO BID or 100 mg/dose PO BID Children > 12 yrs (or >50 kg): Wk 1 & 2: 25 mg/dose PO daily Wk 3 & 4: 25 mg/dose PO BID Increment: 12.5-25 mg/dose PO daily to BID every 7-14 days (25-50 mg/24 hr) Maintenance: 100-200 mg/dose PO BID Maximum: 300 mg/dose PO BID With valproic acid: Wk 1 & 2: 12.5 mg/dose PO daily Wk 3 & 4: 12.5 mg/dose PO BID Increment: 12.5 mg/dose PO daily to BID every 7-14 days (25-50 mg/24 hr) Maintenance: 50-100 mg/dose PO BID Maximum: 150 mg/dose PO BID Bipolar Depression: Adolescents > 12 yrs old (or >50 kg): Monotherapy: Wk 1 & 2: 25 mg PO once daily Wk 3 & 4: 50 mg PO once daily Wk 5: 100 mg PO once daily Maintenance: 200 mg PO once daily With valproic acid (+/- EI-AED): Wk 1 & 2: 25 mg PO every other day Wk 3 & 4: 25 mg PO DAILY Wk 5: 50 mg PO DAILY Maintenance: 100 mg PO DAILY Without valproic acid (+ E-I AED): Wk 1 & 2: 50 mg PO DAILY Wk 3 & 4: 50 mg PO BID Wk 5: 100 mg PO BID Wk 6: 150 mg PO BID Maintenance: up to 200 mg PO BID |
May worsen myoclonic seizures at higher doses and Dravet Syndrome. Increased risk of rash with rapid titration. Must titrate dose slowly. Usually takes 12-15 weeks to achieve maintenance dose. If withheld for > 5 half-lives, restart using initial dosing titration schedule. Adverse effects: drowsiness, blurred vision, headache, insomnia, rash (related initial dose and titration frequency), Stevens-Johnson syndrome (SJS). Skin rash can be serious and progress to SJS. All patients/families should be advised to seek medical attention if a rash develops at any time during treatment. Allergic reaction usually develops within 10-14 days; however, it may appear in up to 3 months after treatment initiation. Enzyme-inhibiting drugs (e.g. valproic acid) may increase half life; while enzyme-inducing drugs (e.g. phenytoin, carbamazepine) may decrease half life. May interact with combination estrogen-progestin or progestin-only contraceptives (reduced lamotrigine levels and possible loss of contraceptive efficacy). Lamotrigine dosage adjustment and/or use of alternative contraceptive method may be necessary. Effective for bipolar depression as monotherapy or adjunctive therapy (adults): open-label studies only in children and adolescents. Little to evidence of efficacy in acute mania or unipolar depression. EI-AED = enzyme inhibiting anti-epileptic drug (e.g. carbamazepine, phenytoin, phenobarbital). Standard Prescription: lamotrigine__mg PO__(frequency) (__mg/kg/24hr) |