lamotrigine extended release

Boxed Warning 10/2025 Dosage and Administration ( 2.1 , 2.2 ) 4/2025 Warnings and Precautions, Serious Skin Rashes 10/2025 Concomitant Use with Estrogen-Containing Products, Including Oral Contraceptives ( 5.9 ) 4/2025 Sudden Unexplained Death in Epilepsy ( 5.12 ) – removal 4/2025

1 INDICATIONS AND USAGE Lamotrigine extended-release is indicated for: adjunctive therapy for primary generalized tonic-clonic seizures (PGTC) 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 is 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 is 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 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 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: The initial dose of lamotrigine extended-release 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 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 products, including 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 with valproate, (2) exceeding the recommended initial dose of lamotrigine extended-release, or (3) exceeding the recommended dose escalation for lamotrigine extended-release. 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 is exceeded and in patients with a history of allergy or rash to other AEDs. It is recommended that lamotrigine extended-release 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, 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 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 in patients on estrogen-containing products including contraceptives and atazanavir/ritonavir, see below and Table 5 . For dosing considerations for lamotrigine extended-release in patients on other drugs known to induce or inhibit glucuronidation, see Table 1 and Table 5. Target Plasma Levels: A therapeutic plasma concentration range has not been established for lamotrigine. Dosing …

3 DOSAGE FORMS AND STRENGTHS 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, round, beige, biconvex, film-coated tablet debossed with “561” on one side and “Par” on the other 50 mg, round, white, biconvex, film-coated tablet debossed with “562” on one side and “Par” on the other 100 mg, round, brown, biconvex, film-coated tablet debossed with “563” on one side and “Par” on the other 200 mg, round, yellow, biconvex, film-coated tablet debossed with “564” on one side and “Par” on the other 250 mg, round, white, biconvex, film-coated tablet debossed with “604” on one side and “Par” on the other 300 mg, round, grey, biconvex, film-coated tablet debossed with “605” on one side and “Par” on the other

4 CONTRAINDICATIONS Lamotrigine extended-release is 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 )

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 ( 5.11 ) ] Most common adverse reactions with use as adjunctive therapy (treatment difference between lamotrigine extended-release 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. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Par Health at 1-800-828-9393 and/or www.parhealth.com or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trial Experience with Lamotrigine Extended-Release 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. Dizziness was the most common reason for withdrawal in the group receiving lamotrigine extended-release (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 (n = 190) Percent of Patients Receiving Adjunctive Placebo (n = 195) Ear and labyrinth disorders Vertigo 3 7 days) into the maintenance phase. These persistent adverse reactions included somnolence and dizziness. There were inadequate data to evaluate the effect of dose and/or concentration on the incidence of adverse reactions because, although patients were randomized to different target doses based upon concomitant AEDs, the plasma exposure was expected to be generally similar among all patients receiving different doses. However, in a randomized, parallel trial comparing placebo with 300 and 500 mg/day of immediate-release lamotrigine, the incidence of the most common adverse reactions ( > 5%) such as ataxia, blurred vision, diplopia, and dizziness were dose related. Less common adverse reactions (2% of patients receiving immediate-release lamotrigine and more frequently than in the placebo group. Body as a Whole: Chest pain. Digestive: Rectal hemorrhage, peptic ulcer. Metabolic and Nutritional: Weight decrease, peripheral edema. Nervous: Hypesthesia, libido increase, decreased reflexes. Respiratory: Epistaxis, dyspnea. Skin and Appendages: Contact dermatitis, dry skin, sweating. Special Senses: Vision abnormality. Urogenital (female patients only) : Dysmenorrhea. Other Clinical Trial Experience Immediate-release lamotrigine has been administered to 6, …

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, and, for women taking estrogen-containing products, including oral contraceptives, in the Warnings and Precautions section [see DOSAGE AND ADMINISTRATION ( 2.1 ) , WARNINGS AND PRECAUTIONS ( 5.9 ) ]. 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 ↓levonorgestrel Decreased lamotrigine concentrations approximately 50%. Decrease in levonorgestrel component by 19%. Carbamazepine and carbamazepine epoxide ↓ lamotrigine ? carbamazepine epoxide Addition of carbamazepine decreases lamotrigine concentration approximately 40%. 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 ? valproate Increased lamotrigine concentrations slightly more than 2-fold. 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 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 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 USE IN SPECIFIC POPULATIONS Pregnancy: Based on animal data may cause fetal harm. ( 8.1 ) Hepatic impairment: Dosage adjustments required in patients with moderate and severe liver impairment. ( 2.1 , 8.6 ) Renal impairment: Reduced maintenance doses may be effective for patients with significant renal impairment. ( 2.1 , 8.7 ) 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, during pregnancy. Encourage women who are taking lamotrigine extended-release 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, 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 …

12.1 Mechanism of Action The precise mechanism(s) by which lamotrigine exerts its anticonvulsant action are unknown. In animal models designed to detect anticonvulsant activity, lamotrigine was effective in preventing seizure spread in the maximum electroshock (MES) and pentylenetetrazol (scMet) tests, and prevented seizures in the visually and electrically evoked after-discharge (EEAD) tests for antiepileptic activity. Lamotrigine also displayed inhibitory properties in the kindling model in rats both during kindling development and in the fully kindled state. The relevance of these models to human epilepsy, however, is not known. One proposed mechanism of action of lamotrigine, the relevance of which remains to be established in humans, involves an effect on sodium channels. In vitro pharmacological studies suggest that lamotrigine inhibits voltage-sensitive sodium channels, thereby stabilizing neuronal membranes and consequently modulating presynaptic transmitter release of excitatory amino acids (e.g., glutamate and aspartate). Effect of Lamotrigine on N-Methyl d-Aspartate-Receptor-Mediated Activity: Lamotrigine did not inhibit N-methyl d-aspartate (NMDA)-induced depolarizations in rat cortical slices or NMDA-induced cyclic GMP formation in immature rat cerebellum, nor did lamotrigine displace compounds that are either competitive or noncompetitive ligands at this glutamate receptor complex (CNQX, CGS, TCHP). The IC 50 for lamotrigine effects on NMDA-induced currents (in the presence of 3 μM of glycine) in cultured hippocampal neurons exceeded 100 μM.

11 DESCRIPTION Lamotrigine Extended-Release, 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: Lamotrigine Extended-Release Tablets are supplied for oral administration as 25 mg (round beige biconvex film-coated), 50 mg (round white biconvex film-coated), 100 mg (round brown biconvex film-coated), 200 mg (round yellow biconvex film-coated), 250 mg (round white biconvex film coated) and 300 mg (round grey biconvex film-coated) tablets. Each tablet contains the labeled amount of lamotrigine and the following inactive ingredients: hypromellose, lactose monohydrate, magnesium stearate, colloidal anhydrous silica (25 mg, 50 mg, 200 mg, 250 mg and 300 mg tablets only), methacrylic acid copolymer, talc, titanium dioxide, triethyl citrate, sodium bicarbonate, sodium laurel sulfate, iron oxide yellow (25 mg and 100 mg tablets only), iron oxide red (25 mg and 100 mg tablets only), D&C Yellow # 10 (200 mg tablet only), FD&C Yellow # 6 (200 mg tablet only) and black iron oxide (300 mg tablet only). Lamotrigine extended-release tablets contain a modified-release eroding formulation as the core. The tablets are coated with an enteric coat and have pore forming ingredient in the coat to enable a controlled release of drug in the acidic environment of the stomach. The combination of the modified-release core and the enteric coat are designed to control the dissolution rate of lamotrigine over a period of approximately 12 to 15 hours, leading to a gradual increase in serum lamotrigine levels. Chemical structure

10 OVERDOSAGE 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 indicated, including frequent monitoring of vital signs and close observation of the patient. If indicated, emesis should be induced; usual precautions should be taken to protect the airway. It is uncertain whether hemodialysis is an effective means of removing lamotrigine from the blood. In 6 renal failure patients, about 20% of the amount of lamotrigine in the body was removed by hemodialysis during a 4-hour session. A Poison Control Center should be contacted for information on the management of overdosage of lamotrigine extended-release.

16 HOW SUPPLIED/STORAGE AND HANDLING Lamotrigine Extended-Release Tablets 25 mg, round, beige, biconvex, film-coated tablet debossed with “561” on one side and “Par” on the other 30 Tablets - (NDC 49884-561-11) 100 Tablets - (NDC 49884-561-01) 500 Tablets - (NDC 49884-561-05) 50 mg, round, white, biconvex, film-coated tablet debossed with “562” on one side and “Par” on the other 30 Tablets - (NDC 49884-562-11) 100 Tablets - (NDC 49884-562-01) 500 Tablets - (NDC 49884-562-05) 100 mg, round, brown, biconvex, film-coated tablet debossed with “563” on one side and “Par” on the other 30 Tablets - (NDC 49884-563-11) 100 Tablets - (NDC 49884-563-01) 500 Tablets - (NDC 49884-563-05) 200 mg, round, yellow, biconvex, film-coated tablet debossed with “564” on one side and “Par” on the other 30 Tablets - (NDC 49884-564-11) 100 Tablets - (NDC 49884-564-01) 500 Tablets - (NDC 49884-564-05) 250 mg, round, white, biconvex, film-coated tablet debossed with “604” on one side and “Par” on the other 30 Tablets – (NDC 49884-604-11) 100 Tablets – (NDC 49884-604-01) 500 Tablets – (NDC 49884-604-05) 300 mg, round, grey, biconvex, film-coated tablet debossed with “605” on one side and “Par” on the other 30 Tablets - (NDC 49884-605-11) 100 Tablets - (NDC 49884-605-01) 500 Tablets - (NDC 49884-605-05) Storage: Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature ] .