Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
Quick facts
- Drug class
- Cytochrome P450 3A4 Inducers [MoA], Cytochrome P450 2C19 Inhibitors [MoA]
- How it is given
- oral
- Type
- human prescription drug
- RxNorm ID
- 199888
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
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.
About this medicine
Topiramate is a sulfamate-substituted monosaccharide. Topiramate tablets are available as 25 mg, 50 mg, 100 mg, and 200 mg round tablets for oral administration. Topiramate is a white crystalline powder with a bitter taste. Topiramate USP is most soluble in alkaline solutions containing sodium hydroxide or sodium phosphate and having a pH of 9 to 10. It is freely soluble in acetone, chloroform, dimethylsulfoxide, and ethanol. The solubility in water is 9.8 mg/mL. Its saturated solution has a pH of 6.3. Topiramate has the molecular formula C 12 H 21 NO 8 S and a molecular weight of 339.37. Topiramate is designated chemically as 2,3:4,5-Di- O -isopropylidene-β-D-fructopyranose sulfamate and has the following structural formula: Topiramate tablets, USP contain the following inactive ingredients: anhydrous lactose, microcrystalline cellulose, pregelatinized maize starch, sodium starch glycolate type A potato, magnesium stearate, polyvinyl alcohol, titanium dioxide, polyethylene glycol and talc. In addition, individual tablets contain: 50 mg tablets: iron oxide yellow 100 mg tablets: iron oxide yellow, and D&C Yellow # 10 Aluminum Lake 200 mg tablets: iron oxide red, lecithin (soya), and iron oxide black chemical-structure
How it works
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.
Who should not take it
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)
Warnings and cautions
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. […]
Reported side effects
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 . […]
Interactions with other medicines
• Contraceptives: decreased contraceptive efficacy and increased breakthrough bleeding, especially at doses greater than 200 mg/day (7.4) • Monitor lithium levels if lithium is used with high-dose topiramate (7.7) 7.1 Antiepileptic Drugs Concomitant administration of phenytoin or carbamazepine with topiramate resulted in a clinically significant decrease in plasma concentrations of topiramate when compared to topiramate given alone. A dosage adjustment may be needed [see Dosage and Administration (2.1), Clinical Pharmacology (12.3) ]. Concomitant administration of valproic acid and topiramate has been associated with hypothermia and hyperammonemia with and without encephalopathy. Examine blood ammonia levels in patients in whom the onset of hypothermia has been reported [see Warnings and Precautions (5.14, 5.16), Clinical Pharmacology (12.3) ]. 7.2 Other Carbonic Anhydrase Inhibitors Concomitant use of topiramate, a carbonic anhydrase inhibitor, with any other carbonic anhydrase inhibitor (e.g., zonisamide or acetazolamide) may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation. Therefore, patients given topiramate concomitantly with another carbonic anhydrase inhibitor should be monitored particularly closely for the appearance or worsening of metabolic acidosis [see Clinical Pharmacology (12.3)] . 7.3 CNS Depressants Concomitant administration of topiramate and alcohol or other CNS depressant drugs has not been evaluated in clinical studies. Because of the potential of topiramate to cause CNS depression, as well as other cognitive and/or neuropsychiatric adverse reactions, topiramate should be used with extreme caution if used in combination with alcohol and other CNS depressants. 7.4 Contraceptives The possibility of decreased contraceptive efficacy and increased breakthrough bleeding may occur in patients taking contraceptive products with topiramate. Patients taking estrogen-containing or progestin-only contraceptives should be asked to report any change in their bleeding patterns. Contraceptive efficacy can be decreased even in the absence of breakthrough bleeding [see Clinical Pharmacology (12.3)]. […]
Use in specific groups
8.1 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. This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll-free number 1-888-233-2334. Information about the North American Drug Pregnancy Registry can be found at http://www.aedpregnancyregistry.org/ . Risk Summary Topiramate can cause fetal harm when administered to a pregnant woman. Data from pregnancy registries indicate that infants exposed to topiramate in utero have an increased risk of major congenital malformations, including but not limited to cleft lip and/or cleft palate (oral clefts), and of being small for gestational age (SGA) [see Human Data] . SGA has been observed at all doses and appears to be dose-dependent. The prevalence of SGA is greater in infants of women who received higher doses of topiramate during pregnancy. In addition, the prevalence of SGA in infants of women who continued topiramate use until later in pregnancy is higher compared to the prevalence in infants of women who stopped topiramate use before the third trimester. In multiple animal species, topiramate produced developmental toxicity, including increased incidences of fetal malformations, in the absence of maternal toxicity at clinically relevant doses [see Animal Data] . All pregnancies have a background risk of birth defects, loss, or other adverse outcomes. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2 to 4% and 15 to 20%, respectively. […]
If too much is taken
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.
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This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 8 June 2026. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.