Topiramate

What it is and how it works

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.

Mechanism class: Cytochrome P450 3A4 Inducers · Cytochrome P450 2C19 Inhibitors

Indications

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 ; 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 Preventive treatment of migraine in patients 12 years of age and older Monotherapy Epilepsy Topiramate tablets and topiramate capsules 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. Adjunctive Therapy Epilepsy Topiramate tablets and topiramate capsules 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. Migraine Topiramate tablets and topiramate capsules are indicated for the preventive treatment of migraine in patients 12 years of age and older.

Dosage and administration (summary)

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 ) 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.

Contraindications

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

Warnings and precautions

Acute myopia and secondary angle closure glaucoma: can lead to permanent visual loss; discontinue topiramate as soon as possible Visual field defects: consider discontinuation of topiramate Oligohidrosis and hyperthermia: monitor decreased sweating and increased body temperature, especially in pediatric patients Metabolic acidosis: baseline and periodic measurement of serum bicarbonate is recommended.

Pregnancy

Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to topiramate during pregnancy. Patients should be encouraged to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry if they become pregnant.

Storage and supply

Topiramate Tablets, USP Topiramate Tablets USP, 200 mg are white to off-white, round-shaped, biconvex, beveled-edge, film-coated tablets debossed with "ZD 13" on one side and plain on the other side and are supplied as follows: NDC: 70518-2001-00 NDC: 70518-2001-01 NDC: 70518-2001-02 NDC: 70518-2001-03 NDC: 70518-2001-04 NDC: 70518-2001-05 NDC: 705…

Source: Topiramate (Topiramate) — US FDA prescribing information, 2026-07-08, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.