Epilepsy

• In Combination with Other Antiepileptic Agents
• PO (Adults and Children >12 yr; Immediate-release, chewable, or orally disintegrating tablets): Patients taking anticonvulsant drugs other than carbamazepine, phenobarbital, phenytoin, primidone, or valproate: 25 mg once daily for first 2 wk, then 50 mg once daily for next 2 wk; then ↑ by 50 mg/day every 1–2 wk to maintenance dose of 225–375 mg/day (in 2 divided doses); Patients taking carbamazepine, phenobarbital, phenytoin, or primidone (and not valproate): 50 mg once daily for first 2 wk, then 50 mg twice daily for next 2 wk; then ↑ by 100 mg/day every 1–2 wk to maintenance dose of 300–500 mg/day (in 2 divided doses); Patients taking regimen containing valproate: 25 mg every other day for first 2 wk, then 25 mg once daily for next 2 wk; then ↑ by 25–50 mg/day every 1–2 wk to maintenance dose of 100–400 mg/day (in 1–2 divided doses) (maintenance dose of 100–200 mg/day if receiving valproate alone).
• PO (Adults and Children ≥13 yr; Extended-release tablets): Patients taking anticonvulsant drugs other than carbamazepine, phenobarbital, phenytoin, primidone, or valproate: 25 mg once daily for first 2 wk, then 50 mg once daily for next 2 wk; then 100 mg once daily for 1 wk, then 150 mg once daily for 1 wk, then 200 mg once daily for 1 wk, then ↑ by 100 mg/day every wk to maintenance dose of 300–400 mg once daily; Patients taking carbamazepine, phenobarbital, phenytoin, or primidone (and not valproate): 50 mg once daily for first 2 wk, then 100 mg once daily for next 2 wk, then 200 mg once daily for 1 wk, then 300 mg once daily for 1 wk, then 400 mg once daily for 1 wk, then ↑ by 100 mg/day every wk to maintenance dose of 400–600 mg once daily; Patients taking regimen containing valproate: 25 mg every other day for first 2 wk, then 25 mg once daily for next 2 wk, then 50 mg once daily for 1 wk, then 100 mg once daily for 1 wk, then 150 mg once daily for 1 wk, then maintenance dose of 200–250 mg once daily.
• PO (Children 2–12 yr; Immediate-release, chewable, or orally disintegrating tablets): Patients taking anticonvulsant drugs other than carbamazepine, phenobarbital, phenytoin, primidone, or valproate : 0.3 mg/kg/day in 1–2 divided doses (rounded down to nearest whole tablet) for first 2 wk, then 0.6 mg/kg/day in 2 divided doses (rounded down to nearest whole tablet) for next 2 wk; then ↑ by 0.6 mg/kg/day (rounded down to nearest whole tablet) every 1–2 wk to maintenance dose of 4.5–7.5 mg/kg/day (not to exceed 300 mg/day in 2 divided doses); Patients taking carbamazepine, phenobarbital, phenytoin, or primidone (and not valproate): 0.6 mg/kg/day in 2 divided doses (rounded down to nearest whole tablet) for first 2 wk, then 1.2 mg/kg/day in 2 divided doses (rounded down to nearest whole tablet) for next 2 wk; then ↑ by 1.2 mg/kg/day (rounded down to nearest whole tablet) every 1–2 wk to maintenance dose of 5–15 mg/kg/day (not to exceed 400 mg/day in 2 divided doses). Patients taking regimen containing valproate: 0.15 mg/kg/day in 1–2 divided doses (rounded down to nearest whole tablet) for first 2 wk, then 0.3 mg/kg in 1–2 divided doses (rounded down to nearest whole tablet) for next 2 wk; then ↑ by 0.3 mg/kg/day (rounded down to nearest whole tablet) every 1–2 wk to maintenance dose of 1–5 mg/kg/day (not to exceed 200 mg/day in 1–2 divided doses) (maintenance dose of 1–3 mg/kg/day if receiving valproate alone).
• Conversion to Monotherapy
• PO (Adults and Children ≥16 yr; Immediate-release, chewable, or orally disintegrating tablets): Patients taking carbamazepine, phenobarbital, phenytoin, or primidone (and not valproate): After achieving a dose of 500 mg/day (as per dosing guidelines above), ↓ dose of other antiepileptic by 20% weekly over 4 wk; Patients taking regimen containing valproate: After achieving a dose of 200 mg/day (as per dosing guidelines above), ↓ valproate dose by 500 mg/day on a weekly basis until a dose of 500 mg/day is achieved. Maintain the valproate dose of 500 mg/day and the lamotrigine dose of 500 mg/day for 1 wk. Then ↑ lamotrigine dose to 300 mg/day and ↓ valproate dose to 250 mg/day, and maintain these doses for 1 wk. Then discontinue valproate and ↑ lamotrigine dose by 100 mg/day every wk until maintenance dose of 500 mg/day is achieved.
• PO (Adults and Children ≥13 yr; Extended-release tablets): Patients taking carbamazepine, phenobarbital, phenytoin, or primidone (and not valproate): After achieving a dose of 500 mg/day (as per dosing guidelines above), ↓ dose of other antiepileptic by 20% weekly over 4 wk. Two wk later, ↓ dose of lamotrigine by 100 mg/day every wk to achieve maintenance dose of 250–300 mg/day; Patients taking regimen containing valproate: After achieving a dose of 150 mg/day (as per dosing guidelines above), ↓ valproate dose by 500 mg/day on a weekly basis until a dose of 500 mg/day is achieved. Maintain the valproate dose of 500 mg/day and the lamotrigine dose of 150 mg/day for 1 wk. Then ↑ lamotrigine dose to 200 mg/day and ↓ valproate dose to 250 mg/day, and maintain these doses for 1 wk. Then discontinue valproate and ↑ lamotrigine dose to 250–300 mg/day; Patients taking anticonvulsant drugs other than carbamazepine, phenobarbital, phenytoin, primidone, or valproate: After achieving a dose of 250–300 mg/day (as per dosing guidelines above), ↓ dose of other antiepileptic by 20% weekly over 4 wk.

Bipolar Disorder

• Escalation Regimen
• PO (Adults ): Patients not taking carbamazepine, phenobarbital, phenytoin, primidone, rifampin, or valproate: 25 mg once daily for first 2 wk, then 50 mg once daily for next 2 wk, then 100 mg once daily for 1 wk, then 200 mg once daily; Patients taking valproate: 25 mg every other day for first 2 wk, then 25 mg once daily for next 2 wk, then 50 mg once daily for 1 wk, then 100 mg once daily; Patients taking carbamazepine, phenobarbital, phenytoin, primidone, or rifampin (and not valproate) 50 mg once daily for first 2 wk, then 100 mg/day (in divided doses) for next 2 wk, then 200 mg/day (in divided doses) for one wk, then 300 mg/day (in divided doses) for 1 wk, then up to 400 mg/day (in divided doses).
• Dosage Adjustment Following Discontinuation of Other Psychotropics
• PO (Adults ): Following discontinuation of valproate (if current dose 100 mg/day):↑ to 150 mg/day for 1 wk, then 200 mg/day; Following discontinuation of carbamazepine, phenobarbital, phenytoin, primidone, or rifampin (if current dose 400 mg/day): 400 mg/day for 1 wk, then 300 mg/day for 1 wk, then 200 mg/day; Following discontinuation of other psychotropics: maintain previous dose.