Adjunct in primary generalized tonic-clonic seizures or partial onset seizures with or without secondary generalization in patients ≥13yrs of age. Conversion to monotherapy in patients ≥13yrs of age with partial seizures who are receiving treatment with a single antiepileptic drug.
Swallow whole. Take once daily. Adjunctive therapy for primary generalized tonic-clonic and partial onset seizures: ≥13yrs: adding to antiepileptic drug (AED) regimens that include valproate: initially 25mg every other day for 2 weeks, then 25mg once daily for 2 weeks, then 50mg once daily for 1 week, then 100mg once daily for 1 week, then 150mg once daily for 1 week; followed by maintenance range 200–250mg/day. For patients not taking carbamazepine, phenytoin, phenobarbital, primidone, or valproate: initially 25mg once daily for 2 weeks, then 50mg once daily for 2 weeks, then 100mg once daily for 1 week, then 150mg once daily for 1 week, then 200mg once daily for 1 week; followed by maintenance range 300–400mg/day. Adding to AED regimens without valproate: initially 50mg once daily for 2 weeks, then 100mg once daily for 2 weeks, then 200mg once daily for 1 week, then 300mg once daily for 1 week, then 400mg once daily for 1 week; followed by maintenance range 400–600mg/day. Conversion from adjunctive therapy with carbamazepine, phenytoin, phenobarbital, or primidone to monotherapy: after achieving a dosage of 500mg/day of Lamictal XR using guidelines above, withdraw concomitant AED by 20% decrements each week over a 4-week period, then 2 weeks after completion of withdrawal of AED, decrease Lamictal XR dose no faster than 100mg/day each week to acheive monotherapy maintenance dosage range of 250–300mg/day. Conversion from adjunctive therapy with valproate to monotherapy: Step 1: achieve dosage of Lamictal XR 150mg/day using guidelines above while maintaining stable dose of valproate; Step 2: maintain Lamictal XR 150mg/day while decreasing valproate dose by decrements no greater than 500mg/day each week to 500mg/day and then maintain for 1 week; Step 3: increase Lamictal XR to 200mg/day while simultaneously decreasing valproate to 250mg/day and maintain for 1 week; Step 4: increase Lamictal XR dose to 250 or 300mg/day and discontinue valproate. Conversion from adjunctive therapy with AED other than the above mentioned: after achieving a dosage of Lamictal XR 250–300mg/day using above guidelines, withdraw concomitant AED by 20% decrements each week for 4-week period; no adjustment to Lamictal XR monotherapy dose is needed. Converting from lamotrigine immediate-release tabs: give initial dose to equal total daily dose of immediate-release; monitor and adjust as needed. Concomitant estrogen-containing oral contraceptives or hormone replacement therapy: see literature. Hepatic impairment: if moderate or severe (w/o ascites) reduce dose by 25%; if severe (w. ascites) reduce dose by 50%.
<13yrs: not recommended.
Discontinue at first sign of rash (unless clearly not drug related); avoid rechallenge. Avoid rapid dose increases and exceeding recommended dose (may increase risk of serious rash). History of allergy or rash to other AEDs (may increase frequency of nonserious rash). Reevaluate if fever, rash, or other hypersensitivity reaction occurs; discontinue if hypersensitivity occurs. Impaired cardiac function. Moderate or severe hepatic impairment. Significant renal impairment: consider reduced dose. Suicidal tendencies (monitor). Increased risk of aseptic meningitis; evaluate and treat if signs/symptoms develop. Avoid abrupt cessation; taper over at least 2 weeks if possible. Elderly. Labor & delivery. Pregnancy (Cat.C). Nursing mothers: not recommended.
Lamotrigine levels increased by valproate. Lamotrigine levels decreased by phenytoin, carbamazepine, phenobarbital, primidone, rifampin. Monitor with other anticonvulsants. Lamotrigine levels may be decreased by oral contraceptives and increased when they are stopped (if monotherapy: adjust dose), and may affect hormonal replacement therapy or other hormonal contraceptive efficacy. May potentiate other folate inhibitors (eg, trimethoprim). Valproate may increase risk of serious rash. Increased incidence of dizziness, diplopia, ataxia, blurred vision with carbamazepine. No apparent effect on lithium levels.
Adults (adjunctive): dizziness, ataxia, somnolence, headache, diplopia, blurred vision, nausea, vomiting. Adults (monotherapy): vomiting, coordination abnormalities, dyspepsia, nausea, dizziness, rhinitis, anxiety, insomnia, pain, weight loss, chest pain, dysmenorrhea, nystagmus, lymphadenopathy. Children (adjunctive): infection, vomiting, fever, dizziness, GI upset, ataxia, tremor, asthenia, bronchitis, flu syndrome, diplopia. Rare: rash (eg, Stevens-Johnson syndrome, toxic epidermal necrolysis, or benign), hypersensitivity, multiorgan failure, blood dyscrasias. XR: also, cerebellar coordination/balance disorder, asthenic conditions, vertigo.
Register pregnant patients exposed to lamotrigine by calling (800) 336-2176.
Tabs 25mg, 100mg—100; 150mg, 200mg—60; Chewable Dispersible tabs 2mg—30; 5mg, 25mg—100; Starter kit 25mg x 35 tabs—1; 25mg x 84 tabs + 100mg x 14 tabs—1; 25mg x 42 tabs + 100mg x 7 tabs—1; ODT Maintenance Packs—30; ODT Titration Kit 25mg x 21 tabs + 50mg x 7 tabs—1; 50mg x 42 tabs + 100mg x 14 tabs—1; 25mg x 14 tabs, 50mg x 14 tabs, 100mg x 7 tabs—1; XR tabs—30; XR Titration Kit 25mg x 21 tabs + 50mg x 7 tabs—1; 50mg x 14 tabs + 100mg x 14 tabs + 200mg x 7 tabs—1; 25mg x 14 tabs + 50mg x 14 tabs + 100mg x 7 tabs—1