Epilepsy Adult & adolescent >12 yr Monotherapy Initially 25 mg once daily for 2 wk, followed by 50 mg once daily for 2 wk. Increase dose by max of 50-100 mg every 1-2 wk. Maintenance dose: 100-200 mg once daily or 2 divided doses up to 500 mg daily.
Add-on therapy Patient taking valproate w/ or w/o any other antiepileptic drugs (AEDs) Initially 25 mg every alternate day for 2 wk, followed by 25 mg once daily for 2 wk. Increase dose by max of 25-50 mg every 1-2 wk. Maintenance dose: 100-200 mg once daily or in 2 divided doses.
Patient taking concomitant 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 daily in 2 divided doses for 2 wk. Increase dose by max of 100 mg every 1-2 wk. Maintenance dose: 200-400 mg daily in 2 divided doses up to 700 mg daily.
Patient taking other medications that do not significantly inhibit or induce lamotrigine glucuronidation Initially 25 mg once daily for 2 wk, followed by 50 mg once daily for 2 wk. Increase dose by max of 50-100 mg every 1-2 wk. Maintenance dose: 100-200 mg once daily or in 2 divided doses.
Childn 2-12 yr Add-on therapy Patient taking valproate w/ or w/o any other (AEDs) Initially 0.15 mg/kg/day once daily for 2 wk, followed by 0.3 mg/kg/day once daily for 2 wk. Increase dose by max of 0.3 mg/kg every 1-2 wk. Maintenance dose: 1-5 mg/kg/day once daily or in 2 divided doses. Max: 200 mg daily.
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. Increase dose by max of 1.2 mg/kg every 1-2 wk. Maintenance dose: 5-15 mg/kg/day in 2 divided doses. Max: 400 mg daily.
Patient taking other medications that do not significantly inhibit or induce lamotrigine glucuronidation Initially 0.3 mg/kg/day once daily or in 2 divided doses for 2 wk, followed by 0.6 mg/kg/day once daily or in 2 divided doses for 2 wk. Increase dose by max of 0.6 mg/kg every 1-2 wk. Maintenance dose: 1-10 mg/kg/day once daily or in 2 divided doses. Max: 200 mg daily.
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 in wk 5. Usual target dose: 100 mg/day 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 in wk 5. May be increased further to 300 mg/day in wk 6. Usual target dose: 400 mg/day in 2 divided doses for wk 7.
Monotherapy or adjunct therapy in patient taking other medications that do not significantly induce or inhibit lamotrigine glucuronidation Initially 25 mg once a day for 2 wk, followed by 50 mg once daily or 2 divided doses for 2 wk. Increase dose to 100 mg/day in wk 5. Usual target dose: 200 mg/day once daily or in 2 divided doses.
Following w/drawal of adjunct therapy w/ lamotrigine glucuronidation inhibitors eg, valproate Increase dose to double the original target stabilization dose & maintain.
Following w/drawal of adjunct therapy w/ lamotrigine glucuronidation inducers depending on original maintenance dose (should be used w/ phenytoin, carbamazepine, phenobarb, primidone or other drugs known to induce lamotrigine glucuronidation) Gradually reduce dose over 3 wk.
Following w/drawal of adjunct therapy w/ other medications that do not significantly inhibit or induce lamotrigine glucuronidation Maintain target dose. General dosing recommendations:
Women taking hormonal contraceptives: Starting hormonal contraceptives in patient already taking maintenance doses & not taking lamotrigine glucuronidation inducers Maintenance dose: May be increased by as much as 2-fold.
Stopping hormonal contraceptives in patient already taking maintenance doses & not taking lamotrigine glucuronidation inducers Maintenance dose: May be decreased by as much as 50%.
Hepatic impairment: Moderate (Child-Pugh grade B) Reduce dose by approx 50%;
Severe (Child-Pugh grade C) Reduce dose by 75%.
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