lamotrigine

1 INDICATIONS AND USAGE Lamotrigine Extended-Release Tablets are 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. ( 1.1 ) conversion to monotherapy in patients aged 13 years and older with partial-onset seizures who are receiving treatment with a single antiepileptic drug（AED）. ( 1.2 ) Limitation of use: Safety and effectiveness in patients younger than 13 years have not been established. ( 1.3 ) 1.1 Adjunctive Therapy Lamotrigine Extended-Release Tablets are indicated as adjunctive therapy for primary generalized tonic-clonic (PGTC) seizures and partial-onset seizures with or without secondary generalization in patients aged 13 years and older. 1.2 Monotherapy Lamotrigine Extended-Release Tablets are indicated for conversion to monotherapy in patients aged 13 years and older with partial-onset seizures who are receiving treatment with a single antiepileptic drug (AED). Safety and effectiveness of Lamotrigine Extended-Release Tablets have not been established (1) as initial monotherapy or (2) for simultaneous conversion to monotherapy from 2 or more concomitant AEDs. 1.3 Limitation of Use Safety and effectiveness of Lamotrigine Extended-Release Tablets for use in patients younger than 13 years have not been established.

2 DOSAGE AND ADMINISTRATION Lamotrigine 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. ( 2.1 ) Initiation of adjunctive therapy and conversion to monotherapy requires slow titration dependent on concomitant AEDs; the prescriber must refer to the appropriate algorithm in Dosage and Administration. ( 2.2 , 2.3 ) · Adjunctive therapy: Target therapeutic dosage range is 200 to 600 mg daily and is dependent on concomitant AEDs. ( 2.2 ) · Conversion to monotherapy: Target therapeutic dosage range is 250 to 300 mg daily. ( 2.3 ) Conversion from immediate-release lamotrigine to Lamotrigine Extended-Release Tablets: The initial dose of Lamotrigine Extended-Release Tablets should match the total daily dose of the immediate-release lamotrigine. Patients should be closely monitored for seizure control after conversion. ( 2.4 ) Do not restart Lamotrigine Extended-Release Tablets in patients who discontinued due to rash unless the potential benefits clearly outweigh the risks. ( 2.1 , 5.1 ) Adjustments to maintenance doses will be necessary in most patients starting or stopping estrogen-containing oral contraceptives. ( 2.1 , 5.9 ) Discontinuation: Taper over a period of at least 2 weeks (approximately 50% dose reduction per week). ( 2.1 , 5.10 ) 2.1 General Dosing Considerations Rash There are suggestions, that the risk of severe, potentially life-threatening rash may be increased by (1) coadministration of Lamotrigine Extended-Release Tablets with valproate, (2) exceeding the recommended initial dose of Lamotrigine Extended-Release Tablets, or (3) exceeding the recommended dose escalation for Lamotrigine Extended-Release Tablets. However, cases have occurred in the absence of these factors [see Boxed Warning] . Therefore, it is important that the dosing recommendations be followed closely. The risk of nonserious rash may be increased when the recommended initial dose and/or the rate of dose escalation for Lamotrigine Extended-Release Tablets is exceeded and in patients with a history of allergy or rash to other AEDs. It is recommended that Lamotrigine Extended-Release Tablets not be restarted in patients who discontinued due to rash associated with prior treatment with lamotrigine unless the potential benefits clearly outweigh the risks. If the decision is made to restart a patient who has discontinued Lamotrigine Extended-Release Tablets, the need to restart with the initial dosing recommendations should be assessed. The greater the interval of time since the previous dose, the greater consideration should be given to restarting with the initial dosing recommendations. If a patient has discontinued lamotrigine for a period of more than 5 half-lives, it is recommended that initial dosing recommendations and guidelines be followed. The half-life of lamotrigine is affected by other concomitant medications [see Clinical Pharmacology (12.3)]. Lamotrigine Extended-Release Tablets Added to Drugs Known to Induce or Inhibit Glucuronidation Because lamotrigine is metabolized predominantly by glucuronic acid conjugation, drugs that are known to induce or inhibit glucuronidation may affect the apparent clearance of lamotrigine. Drugs that induce glucuronidation include carbamazepine, phenytoin, phenobarbital, primidone, rifampin, estrogen-containing products, including oral contraceptives, and the protease inhibitors lopinavir/ritonavir and atazanavir/ritonavir. Valproate inhibits glucuronidation. For dosing considerations for Lamotrigine Extended-Release Tablets in patients on estrogen-containing products including contraceptives and atazanavir/ritonavir, see below and Table 5. For dosing considerations for Lamotrigine Extended-Release Tablets in patients on other drugs known to induce or inhibit glucuronidation, see Table 1 and Table 5. Target Plasma Levels A therapeutic pla…

5 WARNINGS AND PRECAUTIONS • 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 Lamotrigine Extended-Release Tablets if an alternative etiology is not established. ( 5.2 ) • Fatal or life-threatening hypersensitivity reaction: Multiorgan hypersensitivity reactions, also known as drug reaction with eosinophilia and systemic symptoms (DRESS), may be fatal or life threatening. Early signs may include rash, fever, and lymphadenopathy. These reactions may be associated with other organ involvement, such as hepatitis, hepatic failure, blood dyscrasias, or acute multiorgan failure. Lamotrigine Extended-Release Tablets should be discontinued if alternate etiology for this reaction is not found. ( 5.3 ) • Cardiac rhythm and conduction abnormalities: Based on in vitro findings, Lamotrigine Extended-Release Tablets could cause serious arrhythmias and/or death in patients with certain underlying cardiac disorders or arrhythmias. Any expected or observed benefit of Lamotrigine Extended-Release Tablets in an individual patient with clinically important structual or functional heart disease must be carefully weighed against the risk for serious arrythmias and/or death for that patient. ( 5.4 ) • Blood dyscrasias (e.g., neutropenia, thrombocytopenia, pancytopenia): May occur, either with or without an associated hypersensitivity syndrome. Monitor for signs of anemia, unexpected infection, or bleeding. ( 5.5 ) • Suicidal behavior and ideation: Monitor for suicidal thoughts or behaviors. ( 5.6 ) • Aseptic meningitis: Monitor for signs of meningitis. ( 5.7 ) • Medication errors due to product name confusion: Strongly advise patients to visually inspect tablets to verify the received drug is correct. ( 5.8 , 16 , 17 ) 5.1 Serious Skin Rashes [see Boxed Warning] The risk of serious rash caused by treatment with Lamotrigine Extended-Release Tablets is not expected to differ from that with immediate-release lamotrigine [see Boxed Warning] . However, the relatively limited treatment experience with Lamotrigine Extended-Release Tablets makes it difficult to characterize the frequency and risk of serious rashes caused by treatment with Lamotrigine Extended-Release Tablets. Pediatric Population The incidence of serious rash associated with hospitalization and discontinuation of immediate-­release lamotrigine in a prospectively followed cohort of pediatric patients (aged 2 to 16 years) with epilepsy receiving adjunctive therapy with immediate-release lamotrigine was approximately 0.8% (16 of 1,983). When 14 of these cases were reviewed by 3 expert dermatologists, there was considerable disagreement as to their proper classification. To illustrate, one dermatologist considered none of the cases to be Stevens-Johnson syndrome; another assigned 7 of the 14 to this diagnosis. There was 1 rash-related death in this 1,983-patient cohort. Additionally, there have been rare cases of toxic epidermal necrolysis with and without permanent sequelae and/or death in U.S. and foreign postmarketing experience. There is evidence that the inclusion of valproate in a multidrug regimen increases the risk of serious, potentially life-threatening rash in pediatric patients. In pediatric patients who used valproate concomitantly, 1.2% (6 of 482) experienced a serious rash compared with 0.6% (6 of 952) patients not taking valproate. Lamotrigine Extended-Release Tablets are not approved in patients younger than 13 years. Adult Population Serious rash associated with hospitalization and discontinuation of immediate-release lamotrigine occurred in 0.3% (11 of 3,348) of adult patients who received immediate-release lamotrigine in premarketing clinical trials of epilepsy. In worldwide postmarketing experie…

4 CONTRAINDICATIONS Lamotrigine Extended-Release Tablets are contraindicated in patients who have demonstrated hypersensitivity (e.g., rash, angioedema, acute urticaria, extensive pruritus, mucosal ulceration) to the drug or its ingredients [see Boxed Warning , Warnings and Precautions ( 5.1 , 5.3 )] . Hypersensitivity to the drug or its ingredients. ( Boxed Warning , 4 )

7 DRUG INTERACTIONS 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 [see Clinical Pharmacology ( 12.3 )] . 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 inducers of the cytochrome P450 3A4 (CYP3A4) enzyme, which are also known to induce UGT, may also enhance the metabolism of lamotrigine. Those drugs that have been demonstrated to have a clinically significant impact on lamotrigine metabolism are outlined in Table 13. Specific dosing guidance for these drugs is provided in the Dosage and Administration section [see Dosage and Administration ( 2.1 )] . Table 5. Established and Other Potentially Significant Drug Interactions ↓ = Decreased (induces lamotrigine glucuronidation). ↑ = Increased (inhibits lamotrigine glucuronidation). ? = Conflicting data. Concomitant Drug Effect on Concentration of Lamotrigine or Concomitant Drug Clinical Comment Estrogen-containing oral contraceptive preparations containing 30 mcg ethinylestradiol and 150 mcg levonorgestrel ↓ lamotrigine Decreased lamotrigine concentrations approximately 50%. ↓ levonorgestrel Decrease in levonorgestrel component by 19%. Carbamazepine and carbamazepine epoxide ↓ lamotrigine Addition of carbamazepine decreases lamotrigine concentration approximately 40%. ? carbamazepine epoxide May increase carbamazepine epoxide levels. Lopinavir/ritonavir ↓ lamotrigine Decreased lamotrigine concentration approximately 50%. Atazanavir/ritonavir ↓ lamotrigine Decreased lamotrigine AUC approximately 32%. Phenobarbital/primidone ↓ lamotrigine Decreased lamotrigine concentration approximately 40%. Phenytoin ↓ lamotrigine Decreased lamotrigine concentration approximately 40%. Rifampin ↓ lamotrigine Decreased lamotrigine AUC approximately 40%. Valproate ↑ lamotrigine Increased lamotrigine concentrations slightly more than 2-fold. ? valproate There are conflicting study results regarding effect of lamotrigine on valproate concentrations: 1) a mean 25% decrease in valproate concentrations in healthy volunteers, 2) no change in valproate concentrations in controlled clinical trials in patients with epilepsy. Effect of Lamotrigine Extended-Release Tablets on Organic Cationic Transporter 2 Substrates Lamotrigine is an inhibitor of renal tubular secretion via organic cationic transporter 2 (OCT2) proteins [see Clinical Pharmacology ( 12.3 )] . This may result in increased plasma levels of certain drugs that are substantially excreted via this route. Coadministration of Lamotrigine Extended-Release Tablets with OCT2 substrates with a narrow therapeutic index (e.g., dofetilide) is not recommended. Valproate increases lamotrigine concentrations more than 2-fold. ( 7 , 12.3 ) Carbamazepine, phenytoin, phenobarbital, primidone, and rifampin decrease lamotrigine concentrations by approximately 40%. ( 7 , 12.3 ) Estrogen-containing oral contraceptives decrease lamotrigine concentrations by approximately 50%. ( 7 , 12.3 ) Protease inhibitors lopinavir/ritonavir and atazanavir/lopinavir decrease lamotrigine exposure by approximately 50% and 32%, respectively. ( 7 , 12.3 ) Coadministration with organic cationic transporter 2 (OCT2) substrates with narrow therapeutic index is not recommended ( 7 , 12.3 )

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to AEDs, including Lamotrigine Extended-Release Tablets, during pregnancy. Encourage women who are taking Lamotrigine Extended-Release Tablets 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 pregnant women have not detected an increased frequency of major congenital malformations or a consistent pattern of malformations among women exposed to lamotrigine compared with the general population (see Data) . In animal studies, administration of lamotrigine during pregnancy resulted in developmental toxicity (increased mortality, decreased body weight, increased structural variation, neurobehavioral abnormalities) at doses lower than those administered clinically. Lamotrigine decreased fetal folate concentrations in rats, an effect known to be associated with adverse pregnancy outcomes in animals and humans (see Data) . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-associated Maternal and/or Embryofetal Risk Epilepsy, with or without exposure to antiepileptic drugs, has been associated with several adverse outcomes during pregnancy, including preeclampsia, preterm labor, antepartum and postpartum hemorrhage, placental abruption, poor fetal growth, prematurity, fetal death, and maternal mortality. The risk of maternal or fetal injury may be greatest for patients with untreated or poorly controlled convulsive seizures. Women with epilepsy who become pregnant should not abruptly discontinue antiepileptic drugs, including Lamotrigine Extended-Release Tablets, due to the risk of status epilepticus or severe seizures, which may be life-threatening [see Warnings and Precautions (5.10)]. Dose Adjustments During Pregnancy and the Postpartum Period As with other AEDs, physiological changes during pregnancy may affect lamotrigine concentrations and/or therapeutic effect. There have been reports of decreased lamotrigine concentrations during pregnancy and restoration of pre-pregnancy concentrations after delivery. Dose adjustments may be necessary to maintain clinical response. Data Human Data: Data from several international pregnancy registries have not shown an increased risk for malformations overall. The International Lamotrigine Pregnancy Registry reported major congenital malformations in 2.2% (95% CI: 1.6%, 3.1%) of 1,558 infants exposed to lamotrigine monotherapy in the first trimester of pregnancy. The NAAED Pregnancy Registry reported major congenital malformations among 2.0% of 1,562 infants exposed to lamotrigine monotherapy in the first trimester. EURAP, a large international pregnancy registry focused outside of North America, reported major birth defects in 2.9% (95% CI: 2.3%, 3.7%) of 2,514 exposures to lamotrigine monotherapy in the first trimester. The frequency of major congenital malformations was similar to estimates from the general population. The NAAED Pregnancy Registry observed an increased risk of isolated oral clefts: among 2,200 infants exposed to lamotrigine early in pregnancy, the risk of oral clefts was 3.2 per 1,000 (95% CI: 1.4, 6.3), a 3-fold increased risk versus unexposed healthy controls. This finding has not been observed in other large international pregnancy registries. Furthermore, a case-control study based on 21 congenital anomaly registries covering over 10 million births in Europe reported an adjusted odds ratio for isolated oral clefts with lamotrigine exposure of 1.45 (95% CI: 0.8, 2.63). Several meta-analyses have not reported an increased risk of major congenital malformations fol…

6 ADVERSE REACTIONS The following serious adverse reactions are described in more detail in the Warnings and Precautions section of the labeling: • Serious Skin Rashes [see Warnings and Precautions (5.1)] • Hemophagocytic Lymphohistiocytosis [see Warnings and Precautions (5.2)] • Multiorgan Hypersensitivity Reactions and Organ Failure [see Warnings and Precautions (5.3)] • Cardiac Rhythm and Conduction Abnormalities [see Warnings and Precautions (5.4)] • Blood Dyscrasias [see Warnings and Precautions (5. 5 )] • Suicidal Behavior and Ideation [see Warnings and Precautions (5. 6 )] • Aseptic Meningitis [see Warnings and Precautions (5. 7 )] • Withdrawal Seizures [see Warnings and Precautions (5. 10 )] • Status Epilepticus [see Warnings and Precautions (5.1 1 )] • Sudden Unexplained Death in Epilepsy [see Warnings and Precautions (5.1 2 )] Most common adverse reactions with use as adjunctive therapy (treatment difference between Lamotrigine Extended-Release Tablets and placebo≥4%) were dizziness, tremor/intention tremor, vomiting, and diplopia. ( 6.1 ) Most common adverse reactions with use as monotherapy were similar to those seen with previous trials conducted with immediate-release lamotrigine and Lamotrigine Extended-Release Tablets. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Camber Pharmaceuticals Inc at 1-866-495-1995 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trial Experience with Lamotrigine Extended-Release Tablets for Treatment of Primary Generalized Tonic-Clonic and Partial-Onset Seizures Most Common Adverse Reactions in Clinical Trials Adjunctive Therapy in Patients with Epilepsy: Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice. In these 2 trials, adverse reactions led to withdrawal of 4 (2%) patients in the group receiving placebo and 10 (5%) patients in the group receiving Lamotrigine Extended-Release Tablets. Dizziness was the most common reason for withdrawal in the group receiving Lamotrigine Extended-Release Tablets (5 patients [3%]). The next most common adverse reactions leading to withdrawal in 2 patients each (1%) were rash, headache, nausea, and nystagmus. Table 4 displays the incidence of adverse reactions in these two 19-week, double-blind, placebo-controlled trials of patients with PGTC and partial onset seizures. Table 4. Adverse Reactions in Pooled, Placebo-Controlled, Adjunctive Trials in Patients with Epilepsy a Body System/ Adverse Reaction Percent of Patients Receiving Adjunctive Lamotrigine Extended-Release Tablets (n = 190) Percent of Patients Receiving Adjunctive Placebo (n = 195) Ear and labyrinth disorders Vertigo 3 <1 Eye disorders Diplopia Vision blurred 5 3 <1 2 Gastrointestinal disorders Nausea Vomiting Diarrhea Constipation Dry mouth 7 6 5 2 2 4 3 3 <1 1 General disorders and administration site conditions Asthenia and fatigue 6 4 Infections and infestations Sinusitis 2 1 Metabolic and nutritional disorders Anorexia 3 2 Musculoskeletal and connective tissue disorder Myalgia 2 0 Nervous system Dizziness Tremor and intention tremor Somnolence Cerebellar coordination and balance disorder Nystagmus 14 6 5 3 2 6 1 3 0 <1 Psychiatric disorders Depression Anxiety 3 3 <1 0 Respiratory, thoracic, and mediastinal disorders Pharyngolaryngeal pain 3 2 Vascular disorder Hot flush 2 0 a Adverse reactions that occurred in at least 2% of patients treated with Lamotrigine Extended-Release Tablets and at a greater incidence than placebo. Note: In these trials the incidence of nonserious rash was 2% for Lamotrigine Extended-Release Tablets and 3% for placebo. In clinical trials evaluating immediate-release lamotrigine, the rate of serious rash was 0.3% in adults on adjunctive therapy for epilepsy [see Boxed Warning] . Adverse reactions were also analyzed to asse…