Topiramate

1 INDICATIONS AND USAGE Topiramate is indicated for: Epilepsy: initial monotherapy for the treatment of partial-onset or primary generalized tonic-clonic seizures in patients 2 years of age and older (1.1); adjunctive therapy for the treatment of partial-onset seizures, primary generalized tonic-clonic seizures, or seizures associated with Lennox- Gastaut syndrome in patients 2 years of age and older (1.2) Preventive treatment of migraine in patients 12 years of age and older (1.3) 1.1 Monotherapy Epilepsy Topiramate tablets are indicated as initial monotherapy for the treatment of partial-onset or primary generalized tonic-clonic seizures in patients 2 years of age and older. 1.2 Adjunctive Therapy Epilepsy Topiramate tablets are indicated as adjunctive therapy for the treatment of partial-onset seizures, primary generalized tonic-clonic seizures, and seizures associated with Lennox-Gastaut syndrome in patients 2 years of age and older. 1.3 Migraine Topiramate tablets are indicated for the preventive treatment of migraine in patients 12 years of age and older.

12.1 Mechanism of Action The precise mechanisms by which topiramate exerts its anticonvulsant and preventive migraine effects are unknown; however, preclinical studies have revealed four properties that may contribute to topiramate's efficacy for epilepsy and the preventive treatment of migraine. Electrophysiological and biochemical evidence suggests that topiramate, at pharmacologically relevant concentrations, blocks voltage-dependent sodium channels, augments the activity of the neurotransmitter gamma-aminobutyrate at some subtypes of the GABA-A receptor, antagonizes the AMPA/kainate subtype of the glutamate receptor, and inhibits the carbonic anhydrase enzyme, particularly isozymes II and IV.

2 DOSAGE AND ADMINISTRATION Topiramate initial dose, titration, and recommended maintenance dose varies by indication and age group. See Full Prescribing Information for recommended dosage, and dosing considerations in patients with renal impairment, geriatric patients, and patients undergoing hemodialysis (2.1, 2.2, 2.3, 2.4, 2.5, 2.6) 2.1 Dosing in Monotherapy Epilepsy Adults and Pediatric Patients 10 Years of Age and Older The recommended dose for topiramate monotherapy in adults and pediatric patients 10 years of age and older is 400 mg/day in two divided doses. The dose should be achieved by titration according to the following schedule (Table 1): Table 1: Monotherapy Titration Schedule for Adults and Pediatric Patients 10 years and older Morning Dose Evening Dose Week 1 25 mg 25 mg Week 2 50 mg 50 mg Week 3 75 mg 75 mg Week 4 100 mg 100 mg Week 5 150 mg 150 mg Week 6 200 mg 200 mg Pediatric Patients 2 to 9 Years of Age Dosing in patients 2 to 9 years of age is based on weight. During the titration period, the initial dose of topiramate is 25 mg/day nightly for the first week. Based upon tolerability, the dosage can be increased to 50 mg/day (25 mg twice daily) in the second week. Dosage can be increased by 25 to 50 mg/day each subsequent week as tolerated. Titration to the minimum maintenance dose should be attempted over 5 to 7 weeks of the total titration period. Based upon tolerability and clinical response, additional titration to a higher dose (up to the maximum maintenance dose) can be attempted at 25 to 50 mg/day weekly increments. The total daily dose should not exceed the maximum maintenance dose for each range of body weight (Table 2). Table 2: Monotherapy Target Total Daily Maintenance Dosing for Patients 2 to 9 Years of Age Weight (kg) Total Daily Dose (mg/day)* Minimum Maintenance Dose Total Daily Dose (mg/day)* Maximum Maintenance Dose Up to 11 150 250 12 to 22 200 300 23 to 31 200 350 32 to 38 250 350 Greater than 38 250 400 * Administered in two equally divided doses 2.2 Dosing in Adjunctive Therapy Epilepsy Adults (17 Years of Age and Older) The recommended total daily dose of topiramate as adjunctive therapy in adults with partial onset seizures or Lennox-Gastaut Syndrome is 200 to 400 mg/day in two divided doses, and 400 mg/day in two divided doses as adjunctive treatment in adults with primary generalized tonic-clonic seizures. Topiramate should be initiated at 25 to 50 mg/day, followed by titration to an effective dose in increments of 25 to 50 mg/day every week. Titrating in increments of 25 mg/day every week may delay the time to reach an effective dose. Doses above 400 mg/day have not been shown to improve responses in adults with partial-onset seizures. Pediatric Patients 2 to 16 Years of Age The recommended total daily dose of topiramate tablets as adjunctive therapy for pediatric patients 2 to 16 years of age with partial-onset seizures, primary generalized tonic-clonic seizures, or seizures associated with Lennox-Gastaut syndrome is approximately 5 to 9 mg/kg/day in two divided doses. Titration should begin at 25 mg/day (or less, based on a range of 1 to 3 mg/kg/day) nightly for the first week. The dosage should then be increased at 1- or 2-week intervals by increments of 1 to 3 mg/kg/day (administered in two divided doses), to achieve optimal clinical response. Dose titration should be guided by clinical outcome. The total daily dose should not exceed 400 mg/day. 2.3 Dosing for the Preventive Treatment of Migraine The recommended total daily dose of topiramate as treatment for patients 12 years of age and older for the preventive treatment of migraine is 100 mg/day administered in two divided doses (Table 3). The recommended titration rate for topiramate for the preventive treatment of migraine is as follows: Table 3: Preventive Treatment of Migraine Titration Schedule for Patients 12 Years of Age and Older Morning Dose Evening Dose Week 1 None 25 mg Week 2 25 mg 25 mg Week 3 25 mg 50 mg Week

6 ADVERSE REACTIONS The following serious adverse reactions are discussed in more detail in other sections of the labeling: Acute Myopia and Secondary Angle Closure Glaucoma [see Warnings and Precautions (5.1)] Visual Field Defects [see Warnings and Precautions (5.2)] Oligohidrosis and Hyperthermia [see Warnings and Precautions (5.3)] Metabolic Acidosis [see Warnings and Precautions (5.4)] Suicidal Behavior and Ideation [see Warnings and Precautions (5.5)] Cognitive/Neuropsychiatric Adverse Reactions [see Warnings and Precautions (5.6)] Decrease of Bone Mineral Density [see Warnings and Precautions (5.9)] Negative Effects on Growth (Height and Weight) [see Warnings and Precautions (5.10)] Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity Reactions [ see Warnings and Precautions (5.11) ] Serious Skin Reactions [see Warnings and Precautions (5.12)] Anaphylaxis and Angioedema [see Warnings and Precautions (5.13)] Hyperammonemia and Encephalopathy (Without and With Concomitant Valproic Acid [VPA] Use) [see Warnings and Precautions (5.14)] Kidney Stones [see Warnings and Precautions (5.15)] Hypothermia with Concomitant Valproic Acid (VPA) Use [see Warnings and Precautions (5.16)] The data described in the following sections were obtained using topiramate tablets. Epilepsy: Most common (≥10% more frequent than placebo or low-dose topiramate) adverse reactions in adult and pediatric patients were: paresthesia, anorexia, weight loss, speech disorders/related speech problems, fatigue, dizziness, somnolence, nervousness, psychomotor slowing, abnormal vision and fever (6.1) Migraine: Most common (≥5% more frequent than placebo) adverse reactions in adult and pediatric patients were: paresthesia, anorexia, weight loss, difficulty with memory, taste perversion, diarrhea, hypoesthesia, nausea, abdominal pain and upper respiratory tract infection (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Sun Pharmaceutical Industries, Inc. at 1-800-818-4555 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, the incidence of adverse reactions observed in the clinical trials of a drug cannot be directly compared to the incidence of adverse reactions in the clinical trials of another drug, and may not reflect the incidence of adverse reactions observed in practice. Monotherapy Epilepsy Adults 16 Years of Age and Older The most common adverse reactions in the controlled clinical trial (Study 1) that occurred in adults in the 400 mg/day topiramate group and at an incidence higher (≥ 10 %) than in the 50 mg/day group were: paresthesia, weight loss and anorexia (see Table 5). Approximately 21% of the 159 adult patients in the 400 mg/day group who received topiramate as monotherapy in Study 1 discontinued therapy due to adverse reactions. The most common (≥ 2% more frequent than low-dose 50 mg/day topiramate) adverse reactions causing discontinuation were difficulty with memory, fatigue, asthenia, insomnia, somnolence, and paresthesia. Pediatric Patients 6 to 15 Years of Age The most common adverse reactions in the controlled clinical trial (Study 1) that occurred in pediatric patients in the 400 mg/day topiramate group and at an incidence higher (≥10%) than in the 50 mg/day group were fever and weight loss (see Table 5). Approximately 14% of the 77 pediatric patients in the 400 mg/day group who received topiramate as monotherapy in the controlled clinical trial discontinued therapy due to adverse reactions. The most common (≥2% more frequent than low-dose 50 mg/day topiramate) adverse reactions resulting in discontinuation were difficulty with concentration/attention, fever, flushing, and confusion. Table 5 presents the incidence of adverse reactions occurring in at least 3% of adult and pediatric patients treated with 400 mg/day topiramate and occurring with greater incidence than 50 mg/day topiramate. Table 5: Ad

5 WARNINGS AND PRECAUTIONS Acute myopia and secondary angle closure glaucoma: can lead to permanent visual loss; discontinue topiramate as soon as possible (5.1) Visual field defects: consider discontinuation of topiramate (5.2) Oligohidrosis and hyperthermia: monitor decreased sweating and increased body temperature, especially in pediatric patients (5.3) Metabolic acidosis: baseline and periodic measurement of serum bicarbonate is recommended; consider dose reduction or discontinuation of topiramate if clinically appropriate (5.4) Suicidal behavior and ideation: antiepileptic drugs increase the risk of suicidal behavior or ideation (5.5) Cognitive/neuropsychiatric adverse reactions: use caution when operating machinery including cars; depression and mood problems may occur (5.6) Fetal Toxicity: use during pregnancy can cause major congenital malformations, including but not limited to cleft lip and/or palate, and being small for gestational age (5.7) Withdrawal of AEDs: withdraw topiramate gradually (5.8) Decrease in Bone Mineral Density: has been shown to decrease bone mineral density and bone mineral content in pediatric patients (5.9) Negative effects on growth (height and weight): may slow height increase and weight gain; carefully monitor children receiving prolonged therapy (5.10) Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/ Multiorgan Hypersensitivity, serious skin reactions (SJS or TEN), anaphylaxis, and angioedema: Discontinue topiramate if an alternative etiology cannot be established (5.11, 5.12, 5.13) Hyperammonemia/encephalopathy: measure ammonia if encephalopathic symptoms occur (5.14) Kidney stones: avoid use with other carbonic anhydrase inhibitors, drugs causing metabolic acidosis, or in patients on a ketogenic diet (5.15) Hypothermia has been reported with and without hyperammonemia during topiramate treatment with concomitant valproic acid use (5.16) 5.1 Acute Myopia and Secondary Angle Closure Glaucoma Syndrome A syndrome consisting of acute myopia associated with secondary angle closure glaucoma has been reported in patients receiving topiramate. Symptoms include acute onset of decreased visual acuity and/or ocular pain. Ophthalmologic findings can include some or all of the following: myopia, mydriasis, anterior chamber shallowing, ocular hyperemia (redness), choroidal detachments, retinal pigment epithelial detachments, macular striae, and increased intraocular pressure. This syndrome may be associated with supraciliary effusion resulting in anterior displacement of the lens and iris, with secondary angle closure glaucoma. Symptoms typically occur within 1 month of initiating topiramate therapy. In contrast to primary narrow angle glaucoma, which is rare under 40 years of age, secondary angle closure glaucoma associated with topiramate has been reported in pediatric patients as well as adults. The primary treatment to reverse symptoms is discontinuation of topiramate as rapidly as possible, according to the judgment of the treating physician. Other measures, in conjunction with discontinuation of topiramate, may be helpful. Elevated intraocular pressure of any etiology, if left untreated, can lead to serious sequelae including permanent vision loss. 5.2 Visual Field Defects Visual field defects (independent of elevated intraocular pressure) have been reported in clinical trials and in postmarketing experience in patients receiving topiramate. In clinical trials, most of these events were reversible after topiramate discontinuation. If visual problems occur at any time during topiramate treatment, consideration should be given to discontinuing the drug. 5.3 Oligohidrosis and Hyperthermia Oligohidrosis (decreased sweating), infrequently resulting in hospitalization, has been reported in association with topiramate use. Decreased sweating and an elevation in body temperature above normal characterized these cases. Some of the cases were reported after exposure to elevated environmental t

4 CONTRAINDICATIONS Topiramate is contraindicated in patients with a history of hypersensitivity reaction to topiramate, topiramate tablet or any of the inactive ingredients of topiramate tablet. Anaphylaxis and angioedema have occurred [see Warnings and Precautions (5.13)] History of hypersensitivity reaction to topiramate, topiramate tablet or any of the inactive ingredients of topiramate tablet (4, 5.13)

10 OVERDOSAGE Overdoses of topiramate have been reported. Signs and symptoms included convulsions, drowsiness, speech disturbance, blurred vision, diplopia, impaired mentation, lethargy, abnormal coordination, stupor, hypotension, abdominal pain, agitation, dizziness and depression. The clinical consequences were not severe in most cases, but deaths have been reported after overdoses involving topiramate. Topiramate overdose has resulted in severe metabolic acidosis [see Warnings and Precautions (5.4)]. A patient who ingested a dose of topiramate between 96 and 110 g was admitted to a hospital with a coma lasting 20 to 24 hours followed by full recovery after 3 to 4 days. In the event of overdose, topiramate should be discontinued and general supportive treatment given until clinical toxicity has been diminished or resolved. Hemodialysis is an effective means of removing topiramate from the body.