LAMICTAL XR (lamotrigine), an AED of the phenyltriazine class, is chemically unrelated to existing AEDs. Lamotrigine’s chemical name is 3,5-diamino-6-(2,3-dichlorophenyl)- as -triazine, its molecular formula is C 9 H 7 N 5 Cl 2 , and its molecular weight is 256.09. Lamotrigine is a white to pale cream-colored powder and has a pK a of 5.7. Lamotrigine is very slightly soluble in water (0.17 mg/mL at 25°C) and slightly soluble in 0.1 M HCl (4.1 mg/mL at 25°C). The structural formula is: LAMICTAL XR e...

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LAMICTAL XR is indicated for: • adjunctive therapy for primary generalized tonic-clonic seizures and partial-onset seizures with or without secondary generalization in patients aged 13 years and older. • conversion to monotherapy in patients aged 13 years and older with partial-onset seizures who are receiving treatment with a single antiepileptic drug. Limitation of use: Safety and effectiveness in patients younger than 13 years have not been established. 1.1 Adjunctive Therapy LAMICTAL XR is indi...

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Extended-release tablets: 25 mg, 50 mg, 100 mg, 200 mg, 250 mg, and 300 mg. ( 3.1 , 16 ) 3.1 Extended-Release Tablets 25-mg, yellow with white center, round, biconvex, film-coated tablets printed with “LAMICTAL” and “XR 25.” 50-mg, green with white center, round, biconvex, film-coated tablets printed with “LAMICTAL” and “XR 50.” 100-mg, orange with white center, round, biconvex, film-coated tablets printed with “LAMICTAL” and “XR 100.” 200-mg, blue with white center, round, biconvex, film-coated ...

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LAMICTAL XR extended-release tablets are taken once daily, with or without food. Tablets must be swallowed whole and must not be chewed, crushed, or divided. • Do not exceed the recommended initial dosage and subsequent dose escalation. • Initiation of adjunctive therapy and conversion to monotherapy requires slow titration dependent on concomitant antiepileptic drugs (AEDs); the prescriber must refer to the appropriate algorithm in Dosage and Administration. • Adjunctive therapy: Target therapeutic...

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10.1 Human Overdose Experience Overdoses involving quantities up to 15 g have been reported for immediate-release lamotrigine, some of which have been fatal. Overdose has resulted in ataxia, nystagmus, seizures (including tonic-clonic seizures), decreased level of consciousness, coma, and intraventricular conduction delay. 10.2 Management of Overdose There are no specific antidotes for lamotrigine. Following a suspected overdose, hospitalization of the patient is advised. General supportive care is...

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• Life-threatening serious rash and/or rash-related death: Discontinue at the first sign of rash, unless the rash is clearly not drug related. ( Boxed Warning , 5.1 ) • Hemophagocytic lymphohistiocytosis: Consider this diagnosis and evaluate patients immediately if they develop signs or symptoms of systemic inflammation. Discontinue LAMICTAL XR if an alternative etiology is not established. • Fatal or life-threatening hypersensitivity reaction: Multiorgan hypersensitivity reactions, also known as d...

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Significant drug interactions with lamotrigine are summarized in this section. Additional details of these drug interaction studies, which were conducted using immediate-release lamotrigine, are provided in the Clinical Pharmacology section . Uridine 5´-diphospho-glucuronyl transferases (UGT) have been identified as the enzymes responsible for metabolism of lamotrigine. Drugs that induce or inhibit glucuronidation may, therefore, affect the apparent clearance of lamotrigine. Strong or moderate indu...

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8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to AEDs, including LAMICTAL XR, during pregnancy. Encourage women who are taking LAMICTAL XR during pregnancy to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling 1-888-233-2334 or visiting http://www.aedpregnancyregistry.org/. Risk Summary Data from several prospective pregnancy exposure registries and epidemiological studies of pre...

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