Topiramate: Important Safety Information (ISI)

Read this information carefully before starting topiramate. Discuss any questions with your provider.

What Is Topiramate?

Topiramate is an anticonvulsant medication FDA-approved for the treatment of certain seizure disorders and for the prophylaxis of migraine headaches. It is also a component of Qsymia® (phentermine + topiramate extended-release), FDA-approved for chronic weight management. Topiramate is prescribed off-label for binge eating disorder, Night Eating Syndrome, and weight management based on its effects on appetite, food reward signaling, and taste perception.

Contraindications

• Known hypersensitivity to topiramate or any of the inactive ingredients
• (Qsymia® only) Pregnancy
• (Qsymia® only) Glaucoma
• (Qsymia® only) Hyperthyroidism
• (Qsymia® only) Use with monoamine oxidase inhibitors (MAOIs) or within 14 days of MAOI use

Warnings and Precautions

• Acute Myopia and Secondary Angle-Closure Glaucoma: May occur typically within 1 month of initiation. Discontinue topiramate immediately if symptoms develop (sudden vision loss, eye pain).
• Visual Field Defects: Independent of elevated intraocular pressure. Consider discontinuation.
• Oligohidrosis and Hyperthermia: Decreased sweating reported, especially in pediatric patients. Monitor in hot environments.
• Metabolic Acidosis: Hyperchloremic, non-anion gap acidosis. Measure baseline and periodic serum bicarbonate. Reduce dose or discontinue if persistent.
• Suicidal Behavior and Ideation: Antiepileptic drugs increase risk. Monitor for emergence or worsening of depression.
• Cognitive and Neuropsychiatric Adverse Reactions: Confusion, psychomotor slowing, word-finding difficulty, memory problems. Dose-dependent.
• Fetal Toxicity: May cause oral cleft defects. Use effective contraception in patients of childbearing potential.
• Withdrawal of Antiepileptic Drugs: Discontinue topiramate gradually to minimize potential for seizures.
• Hyperammonemia and Encephalopathy: Especially with concomitant valproic acid. Measure ammonia level if symptoms develop.
• Kidney Stones: Topiramate may increase risk; ensure adequate fluid intake.

Most Common Adverse Reactions

Most common adverse reactions in clinical trials:

• Paresthesia (tingling in extremities)
• Anorexia (decreased appetite)
• Weight loss
• Fatigue
• Dizziness
• Somnolence
• Difficulty with memory or concentration
• Word-finding difficulty
• Taste perversion (especially with carbonated beverages)
• Nausea

Drug Interactions

Topiramate may decrease the effectiveness of oral contraceptives at doses of 200 mg/day or higher. Concomitant use with carbonic anhydrase inhibitors increases risk of metabolic acidosis and kidney stones. Concomitant use with valproic acid may increase the risk of hyperammonemia and hypothermia. Alcohol and CNS depressants may increase sedation. Topiramate may increase phenytoin levels.

Use in Specific Populations

• Pregnancy: Topiramate may cause fetal harm including oral cleft defects. Effective contraception is required for patients of childbearing potential. If used during pregnancy, the patient should be enrolled in the North American Antiepileptic Drug (NAAED) Pregnancy Registry.
• Lactation: Topiramate is present in human milk. Consider risk and benefit.
• Pediatric Use: Safety established for specific indications in pediatric patients; consult prescribing information.
• Renal Impairment: Reduce dose by 50% in patients with moderate to severe renal impairment. Removable by hemodialysis.
• Hepatic Impairment: Use with caution in patients with hepatic impairment.