Monograph Details
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Central Nervous System
> Seizure disorders
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LAMICTAL |
| Manufacturer |
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GlaxoSmithKline Pharmaceuticals |
| Legal Classification |
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Rx
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| Pharmacological Class |
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Phenyltriazine. |
| Generic Name |
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Lamotrigine 25mg, 100mg, 150mg, 200mg; scored tabs. |
| Also |
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• LAMICTAL CHEWABLE DISPERSIBLE TABS
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| Indications |
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Adjunct in partial seizures, Lennox-Gastaut syndrome, or primary generalized tonic-clonic seizures in adults and children (≥2yrs). Conversion to monotherapy in adults (≥16yrs) with partial seizures who are on carbamazepine, phenytoin, phenobarbital, primidone, or valproate as a single antiepileptic drug (AED). |
| Children |
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Chew tabs: give only whole tabs, round dose down to nearest whole tab (may be swallowed whole, chewed, or mixed in water or diluted fruit juice). <2yrs: not recommended. 2–12yrs: Adding to AED regimens that include valproate: initially 0.15mg/kg per day in 1 or 2 divided doses for 2 weeks, then 0.3mg/kg per day in 1 or 2 divided doses for 2 weeks; may increase by 0.3mg/kg per day at 1–2 week intervals in 1 or 2 divided doses; usual maintenance 1–5mg/kg per day; max 200mg/day in 1 or 2 divided doses. Adding to valproate only: usual maintenance 1–3mg/kg per day. Adding to AED regimens other than carbamazepine, phenytoin, phenobarbital, primidone, or valproate: initially 0.3mg/kg per day in 1 or 2 divided doses for 2 weeks, then 0.6mg/kg per day in 2 divided doses for 2 weeks; may increase by 0.6mg/kg per day at 1–2 week intervals; usual maintenance 4.5–7.5mg/kg per day; max 300mg/day in 2 divided doses. Adding to AED regimens without valproate: initially 0.6mg/kg per day in 2 divided doses for 2 weeks, then 1.2mg/kg per day in 2 divided doses for 2 weeks; may increase by 1.2mg/kg per day at 1–2 week intervals; usual maintenance 5–15mg/kg per day; max 400mg/day in 2 divided doses. Patients <30kg: may need higher (≤50%) maintenance dose. |
| Adults |
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Adding to antiepileptic drug (AED) regimens that include valproate: initially 25mg every other day for 2 weeks, then 25mg once daily for 2 weeks; may increase by 25–50mg/day at 1–2 week intervals; usual maintenance 100–400mg/day in 1 or 2 divided doses. Adding to valproate only: usual maintenance 100–200mg/day. Adding to AED regimens other than carbamazepine, phenytoin, phenobarbital, primidone, or valproate: initially 25mg once daily for 2 weeks; then 50mg once daily for 2 weeks; may increase by 50mg/day at 1–2 week intervals; usual maintenance 225–375mg/day in 2 divided doses. Adding to AED regimens without valproate: initially 50mg per day for 2 weeks, then 100mg daily in 2 divided doses for 2 weeks; may increase by 100mg/day at 1–2 week intervals; usual maintenance 300–500mg/day in 2 divided doses. Converting from one AED (not valproate) to lamotrigine monotherapy (first titrate lamotrigine, then withdraw AED): initially 50mg per day for 2 weeks, then 100mg daily in 2 divided doses for 2 weeks; may increase by 100mg/day at 1–2 week intervals to 500mg/day in 2 divided doses. Then reduce AED dose by 20% per week for 4 wks. Converting from valproate to lamotrigine monotherapy: see literature. 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%. |
| Precautions |
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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. Significant renal impairment: consider reduced dose. Suicidal tendencies (monitor). Avoid abrupt cessation; taper over at least 2 weeks if possible. Elderly. Labor & delivery. Pregnancy (Cat.C). Nursing mothers: not recommended. |
| Interactions |
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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. |
| Adverse Reactions |
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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, 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. |
| Extra Text |
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Note: Register pregnant patients exposed to lamotrigine by calling (800) 336-2176. |
| How Supplied |
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 |
| Additional Resources |
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• Related Prescribing Note |
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