Epilepsy Adult >12 yr Monotherapy Initially 25 mg once daily for 2 wk, followed by 50 mg once daily for 2 wk. Increase dose by max 50-100 mg every 1-2 wk. Maintenance: 100-200 mg/day once daily or as 2 divided doses up to 500 mg/day.
Add-on therapy w/ valproate Initially 25 mg every alternate day for 2 wk, followed by 25 mg once daily for 2 wk. Increase dose by max 25-50 mg every 1-2 wk. Maintenance: 100-200 mg/day once daily or in 2 divided doses.
Patient taking concomitant antiepileptic drugs (AEDs) or other medications that induce lamotrigine glucuronidation w/ or w/o other AEDs (except valproate) Initially 50 mg once daily for 2 wk, followed by 100 mg/day in 2 divided doses for 2 wk. Increase dose by max 100 mg every 1-2 wk. Maintenance: 200-400 mg/day in 2 divided doses up to 700 mg/day.
Patient taking other medications that do not significantly inhibit/induce lamotrigine glucuronidation Initially 25 mg once daily for 2 wk followed by 50 mg once daily for 2 wk. Increase dose by max 50-100 mg every 1-2 wk. Maintenance: 100-200 mg/day or in 2 divided doses.
Childn 2-12 yr Monotherapy (in typical absence seizure) Initially 0.3 mg/kg once daily or in 2 divided doses for 2 wk, followed by 0.6 mg/kg once daily or in 2 divided doses for 2 wk. Thereafter, increase dose by max 0.6 mg/kg 1-2 wkly. Maintenance: 1-10 mg/kg once daily or in 2 divided doses.
Add-on therapy w/ valproate Initially 0.15 mg/kg/day for 2 wk, followed by 0.3 mg/kg once daily for 2 wk. Thereafter, increase dose by max 0.3 mg/kg every 1-2 wk. Maintenance: 1-5 mg/kg once daily or in 2 divided doses. Max: 200 mg/day.
Patient taking concomitant AEDs or other medications that induce lamotrigine glucuronidation w/ or w/o other AEDs (except valproate) Initially 0.6 mg/kg/day in 2 divided doses for 2 wk, followed by 1.2 mg/kg/day in 2 divided doses for 2 wk. Thereafter, increase dose by max 1.2 mg/kg every 1-2 wk. Maintenance: 5-15 mg/kg/day in 2 divided doses. Max: 400 mg/day.
Patient taking other medications that do not significantly inhibit or induce lamotrigine glucuronidation Initially 0.3 mg/kg once daily or in 2 divided doses for 2 wk, followed by 0.6 mg/kg once daily or in 2 divided doses for 2 wk. Thereafter, increase dose by max 0.6 mg/kg every 1-2 wk. Maintenance: 1-10 mg/kg once daily or in 2 divided doses. Max: 200 mg/day.
Bipolar disorder Adult ≥18 yr Adjunct therapy w/ lamotrigine glucuronidation inhibitors eg, valproate Initially 25 mg every alternate day for 2 wk, followed by 25 mg once daily for 2 wk. Increase dose to 50 mg once daily or in 2 divided doses for 1 wk. Optimal response is achieved w/ 100 mg once daily or in 2 divided doses. Max: 200 mg daily.
Adjunct therapy w/ lamotrigine glucuronidation inducers in patient not taking inhibitors eg, valproate (should be used w/ phenytoin, carbamazepine, phenobarb, primidone & other drugs known to induce lamotrigine glucuronidation) Initially 50 mg once daily for 2 wk, followed by 100 mg/day in 2 divided doses for 2 wk. Increase dose to 200 mg/day in 2 divided doses for 1 wk. May be increased further to 300 mg/day for 1 wk to optimal response of 400 mg/day in 2 divided doses for succeeding wk.
Monotherapy or adjunctive therapy w/ other medications that do not significantly induce/inhibit lamotrigine glucuronidation Initially 25 mg once daily for 2 wk, followed by 50 mg once daily or in 2 divided doses for 2 wk. Increase dose to 100 mg/day for 1 wk. Optimal response achieved w/ 200 mg/day or in 2 divided doses.
Women taking hormonal contraceptives already taking maintenance doses & not taking lamotrigine glucuronidation inducers Increased by 50-100 mg/day every wk.
Stopping hormonal contraceptives in patient already taking maintenance doses & not taking lamotrigine glucuronidation inducers Gradually decrease daily dose by 50-100 mg each wk (at rate not exceeding 25% total daily dose/wk) over a period of 3 wk.
Hepatic impairment Initial, escalation & maintenance doses should be generally reduced by approx 50% in moderate (Child-Pugh grade B) & 75% in severe (Child-Pugh grade C) impairment.
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