Therapeutic Classification: anticonvulsants
Absorption: 100% absorbed following oral administration; IV administration results in complete bioavailability.
Distribution: Unknown.
Protein Binding: <15%.
Metabolism/Excretion: Partially metabolized by the liver; 40% excreted in urine as unchanged drug; 30% as a metabolite.
Half-Life: 13 hr.
Partial-Onset Seizures
- PO IV (Adults ): Monotherapy (immediate-release PO or IV): 100 mg twice daily; may ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 150200 mg twice daily; may also initiate therapy with 200-mg single loading dose followed 12 hr later by 100 mg twice daily for 1 wk; may then ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 150200 mg twice daily. Monotherapy (extended-release PO)200 mg once daily; may ↑ weekly by 100 mg once daily up to a maintenance dose of 300400 mg once daily; Adjunctive therapy (immediate-release PO or IV): 50 mg twice daily; may ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 100200 mg twice daily; may also initiate therapy with 200-mg single loading dose followed 12 hr later by 100 mg twice daily for 1 wk; may then ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 100200 mg twice daily. Adjunctive therapy (extended-release PO): 100 mg once daily; may ↑ weekly by 100 mg once daily up to a maintenance dose of 200400 mg once daily.
- PO IV (Children ≥1 mo and ≥50 kg): Monotherapy (immediate-release PO or IV): 50 mg twice daily; may ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 150200 mg twice daily; may also initiate therapy with 200-mg single loading dose followed 12 hr later by 100 mg twice daily for 1 wk; may then ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 150200 mg twice daily. Monotherapy (extended-release PO): 100 mg once daily; may ↑ weekly by 100 mg once daily up to a maintenance dose of 300400 mg once daily. Adjunctive therapy (immediate-release PO or IV): 50 mg twice daily; may ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 100200 mg twice daily; may also initiate therapy with 200-mg single loading dose followed 12 hr later by 100 mg twice daily for 1 wk; may then ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 100200 mg twice daily. Adjunctive therapy (extended-release PO): 100 mg once daily; may ↑ weekly by 100 mg once daily up to a maintenance dose of 200400 mg once daily.
- PO IV (Children ≥1 mo and 30<50 kg): Monotherapy or adjunctive therapy (immediate-release PO or IV): 1 mg/kg twice daily; may ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 24 mg/kg twice daily; may also initiate therapy with 4 mg/kg single loading dose followed 12 hr later by 2 mg/kg twice daily for 1 wk; may then ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 24 mg/kg twice daily.
- PO IV (Children ≥1 mo and 6<30 kg): Monotherapy or adjunctive therapy (immediate-release PO or IV): 1 mg/kg twice daily; may ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 36 mg/kg twice daily; may also initiate therapy with 4.5 mg/kg single loading dose followed 12 hr later by 3 mg/kg twice daily for 1 wk; may then ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 36 mg/kg twice daily.
- PO (Children ≥1 mo and <6 kg): Monotherapy or adjunctive therapy (immediate-release PO or IV): 1 mg/kg twice daily; may ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 3.757.5 mg/kg twice daily; may also initiate therapy with 3.75 mg/kg twice daily for 1 wk; may then ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 3.757.5 mg/kg twice daily.
- IV (Children ≥1 mo and <6 kg): Monotherapy or adjunctive therapy (immediate-release PO or IV): 0.66 mg/kg 3 times daily; may ↑ weekly by 2 mg/kg/day in 3 divided doses up to a maintenance dose of 2.55 mg/kg 3 times daily; may also initiate therapy with 2.5 mg/kg 3 times daily for 1 wk; may then ↑ weekly by 2 mg/kg/day in 3 divided doses up to a maintenance dose of 2.55 mg/kg 3 times daily.
Renal Impairment
- PO IV (Adults and Children ≥1 mo): CCr ≤30 mL: Monotherapy or adjunctive therapy (immediate-release PO or IV): ↓ maximum dose by 25%. Monotherapy or adjunctive therapy (extended-release PO): Not to exceed maximum dose of 300 mg once daily.
Hepatic Impairment
- PO IV (Adults and Children ≥1 mo): Mild or moderate hepatic impairment: Monotherapy or adjunctive therapy (immediate-release PO or IV): ↓ maximum dose by 25%. Monotherapy or adjunctive therapy (extended-release PO): Not to exceed dose of 300 mg once daily.
Primary Generalized Tonic-Clonic Seizures
- PO IV (Adults ): Adjunctive therapy (immediate-release PO or IV): 50 mg twice daily; may ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 100200 mg twice daily; may also initiate therapy with 200-mg single loading dose followed 12 hr later by 100 mg twice daily; may ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 100200 mg twice daily.Adjunctive therapy (extended-release PO): 100 mg once daily; may ↑ weekly by 100 mg once daily up to a maintenance dose of 200400 mg once daily.
- PO IV (Children ≥4 yr and ≥50 kg): Adjunctive therapy (immediate-release PO or IV): 50 mg twice daily; may ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 100200 mg twice daily; may also initiate therapy with 200-mg single loading dose followed 12 hr later by 100 mg twice daily; may ↑ weekly by 100 mg/day in 2 divided doses up to a maintenance dose of 100200 mg twice daily. Adjunctive therapy (extended-release PO): 100 mg once daily; may ↑ weekly by 100 mg once daily up to a maintenance dose of 200400 mg once daily.
- PO IV (Children ≥4 yr and 30<50 kg): Adjunctive therapy (immediate-release PO or IV): 1 mg/kg twice daily; may ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 24 mg/kg twice daily; may also initiate therapy with 4 mg/kg single loading dose followed 12 hr later by 2 mg/kg twice daily; may ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 24 mg/kg twice daily.
- PO IV (Children ≥4 yr and 11<30 kg): Adjunctive therapy (immediate-release PO or IV): 1 mg/kg twice daily; may ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 36 mg/kg twice daily; may also initiate therapy with 4.5 mg/kg single loading dose followed 12 hr later by 3 mg/kg twice daily; may ↑ weekly by 2 mg/kg/day in 2 divided doses up to a maintenance dose of 36 mg/kg twice daily.
Renal Impairment
- PO IV (Adults and Children ≥4 yr): CCr ≤30 mL/min: Adjunctive therapy (immediate-release PO or IV): ↓ maximum dose by 25%. Adjunctive therapy (extended-release PO): Not to exceed dose of 300 mg once daily.
Hepatic Impairment
- PO IV (Adults and Children ≥4 yr): Mild or moderate hepatic impairment: Adjunctive therapy (immediate-release PO or IV): ↓ maximum dose by 25%. Adjunctive therapy (extended-release PO): Not to exceed dose of 300 mg once daily.