Nursing2024 Drug Handbook

842 lamotrigine

other day for 2 weeks; then 25 mg PO daily for 2 weeks; then 50 mg PO daily for 1 week; then 100 mg PO daily for 1 week; then 150 mg PO daily for 1 week. Daily main- tenance dose is 200 to 250 mg. Adults and children age 13 and older not tak- ing carbamazepine, phenytoin, phenobarbi- tal, primidone, or valproate: 25 mg extended- release PO daily for 2 weeks; then 50 mg PO daily for 2 weeks; then 100 mg PO daily for 1 week; then 150 mg PO daily for 1 week; then 200 mg PO daily for 1 week. Daily main- tenance dose is 300 to 400 mg. Adults and children older than age 12 taking anticonvulsant drugs but not carbamazepine, phenytoin, phenobarbital, primidone, or val- proate: 25 mg immediate-release PO daily for 1 to 2 weeks; then 50 mg PO daily for another 2 weeks. Continue to increase by 50 mg/day every 1 to 2 weeks until an effective main- tenance dose is reached. Daily maintenance dose is 225 to 375 mg PO daily in two divided doses. Adults and children older than age 12 tak- ing carbamazepine, phenytoin, phenobarbi- tal, or primidone but not valproate: 50 mg immediate-release PO daily for 2 weeks; then 100 mg PO daily in two divided doses for 2 weeks. Increase, as needed, by 100 mg daily every 1 to 2 weeks. Usual maintenance dosage is 300 to 500 mg PO daily in two di- vided doses. Adults and children age 13 and older tak- ing carbamazepine, phenytoin, phenobarbi- tal, or primidone but not valproate: 50 mg extended-release PO daily for 2 weeks; then 100 mg PO daily for 2 weeks; then 200 mg PO daily for 1 week; then 300 mg PO daily for 1 week; then 400 mg PO daily for 1 week. Daily maintenance dose is 400 to 600 mg. Children ages 2 to 12 weighing 6.7 to 40 kg taking valproate: 0.15 mg/kg immediate- release PO daily in one or two divided doses (rounded down to nearest whole tablet) for 2 weeks. Increase to 0.3 mg/kg daily in one or two divided doses for 2 weeks, followed by increasing the daily dose every 1 or 2 weeks with an additional 0.3 mg/kg daily in one or two divided doses. Thereafter, usual main- tenance dosage is 1 to 5 mg/kg daily (max- imum, 200 mg daily in one to two divided doses). In patients weighing less than 30 kg, maintenance dosage may need to be increased by as much as 50% based on clinical re- sponse.

Children ages 2 to 12 weighing 6.7 to 40 kg taking anticonvulsant drugs but not carba- mazepine, phenytoin, phenobarbital, prim- idone, or valproate: 0.3 mg/kg immediate- release PO daily in one or two divided doses (rounded down to the nearest whole tablet) for 2 weeks; then 0.6 mg/kg PO daily in two divided doses for another 2 weeks; then in- crease the daily dose every 1 to 2 weeks with an additional 0.6 mg/kg PO daily in two di- vided doses. Thereafter, usual maintenance dose is 4.5 to 7.5 mg/kg PO daily. Maximum dose is 300 mg daily in two divided doses. In patients weighing less than 30 kg, mainte- nance dosage may need to be increased by as much as 50% based on clinical response. Children ages 2 to 12 weighing 6.7 to 40 kg taking carbamazepine, phenytoin, pheno- barbital, or primidone but not valproate: 0.6 mg/kg immediate-release PO daily in two divided doses (rounded down to near- est whole tablet) for 2 weeks. Increase to 1.2 mg/kg PO daily in two divided doses for 2 weeks; then increase the daily dose every 1 to 2 weeks with an additional 1.2 mg/kg daily in two divided doses. Usual mainte- nance dosage is 5 to 15 mg/kg PO daily (max- imum 400 mg daily in two divided doses). In patients weighing less than 30 kg, main- tenance dosage may need to be increased by as much as 50% based on clinical response. ➤ To convert patients from therapy with an enzyme-inducing AED alone to lamo- trigine therapy Adults and children age 16 and older: Add 50 mg immediate-release PO once daily to current drug regimen for 2 weeks, followed by 100 mg PO daily in two divided doses for 2 weeks. Then increase daily dosage by 100 mg every 1 to 2 weeks until maintenance dose of 500 mg daily in two divided doses is reached. The concomitant hepatic enzyme- inducing AED can then be gradually reduced by 20% decrements weekly for 4 weeks. ➤ To convert patients with partial seizures from adjunctive therapy with valproate to therapy with lamotrigine alone Adults and children age 16 and older: Add immediate-release form until 200 mg daily is achieved; then gradually decrease valproate to 500 mg daily by decrements of no more than 500 mg daily per week. Maintain these dosages for 1 week, then increase lamotrigine to 300 mg daily while decreasing valproate to 250 mg daily. Maintain these dosages for

Reactions in bold italics are life-threatening . Interactions may have a rapid onset or a delayed onset .