2.1 Epilepsy
It is not necessary to monitor topiramate plasma concentrations to optimize topiramate therapy.
On occasion, the addition of topiramate tablets to phenytoin may require an adjustment of the dose of phenytoin to achieve optimal clinical outcome. Addition or withdrawal of phenytoin and/or carbamazepine during adjunctive therapy with topiramate tablets may require adjustment of the dose of topiramate tablets.
Because of the bitter taste, tablets should not be broken.
Topiramate tablets can be taken without regard to meals.
Monotherapy Use
Adults and Pediatric Patients 10 Years and Older
The recommended dose for topiramate tablets monotherapy in adults and pediatric patients 10 years of age and older is 400 mg/day in two divided doses. Approximately 58% of patients randomized to 400 mg/day achieved this maximal dose in the monotherapy controlled trial; the mean dose achieved in the trial was 275 mg/day. 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
Children Ages 2 to <10 Years
Dosing of topiramate as initial monotherapy in children 2 to < 10 years of age with partial onset or primary generalized tonic-clonic seizures was based on a pharmacometric bridging approach [see Clinical Studies (14.1)].
Dosing in patients 2 to <10 years is based on weight. During the titration period, the initial dose of topiramate tablets should be 25 mg/day administered 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 <10 Years
Weight (kg)
Total Daily Dose (mg/day)* Minimum Maintenance Dose
Total Daily Dose (mg/day)* Maximum Maintenance Dose
*
Administered in two equally divided doses
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
Adjunctive Therapy Use
Adults 17 Years of Age and Over - Partial Onset Seizures, Primary Generalized Tonic-Clonic Seizures, or Lennox-Gastaut Syndrome
The recommended total daily dose of topiramate tablets as adjunctive therapy in adults with partial onset seizures 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. It is recommended that therapy 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 (600, 800 or 1,000 mg/day) have not been shown to improve responses in dose-response studies in adults with partial onset seizures. Daily doses above 1,600 mg have not been studied.
In the study of primary generalized tonic-clonic seizures, the initial titration rate was slower than in previous studies; the assigned dose was reached at the end of 8 weeks [see Clinical Studies (14.1)].
Pediatric Patients Ages 2 to 16 Years – Partial Onset Seizures, Primary Generalized Tonic-Clonic Seizures, or Lennox-Gastaut Syndrome
The recommended total daily dose of topiramate tablets as adjunctive therapy for pediatric patients 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.
In the study of primary generalized tonic-clonic seizures, the initial titration rate was slower than in previous studies; the assigned dose of 6 mg/kg/day was reached at the end of 8 weeks [see Clinical Studies (14.1)].
Additional pediatric use information for patients ages 12 to 17 years is approved for Janssen Pharmaceuticals, Inc.’s TOPAMAX (topiramate) Tablets and Sprinkle Capsules. However, due to Janssen Pharmaceuticals, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information.
2.4 Patients with Renal Impairment
In renally impaired subjects (creatinine clearance less than 70 mL/min/1.73 m2), one-half of the usual adult dose is recommended. Such patients will require a longer time to reach steady-state at each dose.
2.5 Geriatric Patients (Ages 65 Years and Over)
Dosage adjustment may be indicated in the elderly patient when impaired renal function (creatinine clearance rate <70 mL/min/1.73 m2) is evident [see Clinical Pharmacology (12.3)].
2.6 Patients Undergoing Hemodialysis
Topiramate is cleared by hemodialysis at a rate that is 4 to 6 times greater than a normal individual. Accordingly, a prolonged period of dialysis may cause topiramate concentration to fall below that required to maintain an anti-seizure effect. To avoid rapid drops in topiramate plasma concentration during hemodialysis, a supplemental dose of topiramate may be required. The actual adjustment should take into account 1) the duration of dialysis period, 2) the clearance rate of the dialysis system being used, and 3) the effective renal clearance of topiramate in the patient being dialyzed.
2.7 Patients with Hepatic Disease
In hepatically impaired patients, topiramate plasma concentrations may be increased. The mechanism is not well understood.