Topiramate
TOPAMAX
What it isSodium-channel blocking, GABA-enhancing and glutamate-blocking antiepileptic; seizures and migraine prevention.
Why this oneOne of the few migraine preventives with weight loss rather than weight gain.
What limits itCognitive slowing often ends treatment. Watch for stones, metabolic acidosis and fetal oral clefts; higher exposure can reduce contraceptive efficacy.
FDA-approved for
- seizures (1996)
- migraine prophylaxis (2004)
Off-label
- alcohol use disorder
- binge eating
- weight loss
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Epilepsy — initial monotherapy (partial-onset or primary generalized tonic-clonic) | Adults & peds ≥10 y | 25 mg BID (week 1) | 200 mg BID (400 mg/day) via 6-wk schedule | 400 mg/day |
| Epilepsy — initial monotherapy | Peds 2–9 y (weight-based) | 25 mg QHS (week 1); 25 mg BID week 2 | Min maintenance 150–250 mg/day BID by weight, over 5–7 wk | 250–400 mg/day BID by weight; ≤400 mg/day |
| Epilepsy — adjunctive (partial-onset, Lennox-Gastaut) | Adults ≥17 y | 25–50 mg QD | 200–400 mg/day BID | 400 mg/day (no added benefit above) |
| Epilepsy — adjunctive (primary generalized tonic-clonic) | Adults ≥17 y | 25–50 mg QD | 400 mg/day BID | 400 mg/day |
| Epilepsy — adjunctive (POS, PGTC, Lennox-Gastaut) | Peds 2–16 y | 25 mg QHS (or 1–3 mg/kg/day) week 1 | 5–9 mg/kg/day BID | 400 mg/day |
| Migraine — preventive treatment | Adults & peds ≥12 y | 25 mg QHS (week 1) | 50 mg BID (100 mg/day) by week 4 | 100 mg/day |
Titration Increase at weekly intervals (monotherapy & adjunctive adults: +25–50 mg/day qwk; peds adjunctive: +1–3 mg/kg/day q1–2wk; migraine: qwk per schedule); longer intervals OK if needed
Renal CrCl <70 mL/min/1.73 m²: one-half usual adult dose; hemodialysis: supplemental dose may be required
Hepatic No adjustment specified; plasma clearance ↓26% in moderate–severe impairment
Instructions
- May take without regard to meals
- Do not break tablets (bitter taste)
- Sprinkle capsules: swallow whole, or open and sprinkle on a teaspoon of soft food — swallow immediately without chewing; do not store mixture
- Withdraw gradually to minimize risk of seizures/increased seizure frequency
Cautions
- Acute myopia with secondary angle-closure glaucoma (typically within 1 mo of start) — discontinue ASAP; risk of permanent vision loss
- Visual field defects — consider discontinuation
- Oligohidrosis and hyperthermia, especially peds — monitor in hot weather
- Hyperchloremic non-anion-gap metabolic acidosis — baseline & periodic serum bicarbonate; reduce dose/taper off if persistent
- Suicidal behavior and ideation (AED class effect) — monitor mood
- Cognitive/neuropsychiatric reactions: psychomotor slowing, memory/concentration/speech problems, somnolence; caution driving
- Fetal toxicity (oral clefts, SGA)
- Decreased bone mineral density and slowed growth (height/weight) in peds
- DRESS/multiorgan hypersensitivity, SJS/TEN, anaphylaxis, angioedema — discontinue
- Hyperammonemia/encephalopathy (with or without valproate) — check ammonia if symptomatic
- Kidney stones — avoid other carbonic anhydrase inhibitors, acidosis-causing drugs, ketogenic diet
- Hypothermia with concomitant valproate
Adverse reactions
- Epilepsy (≥10% vs comparator): paresthesia, anorexia, weight loss, speech problems, fatigue, dizziness, somnolence, nervousness, psychomotor slowing, abnormal vision, fever
- Migraine (≥5% vs placebo): paresthesia, anorexia, weight loss, memory difficulty, taste perversion, diarrhea, hypoesthesia, nausea, abdominal pain, URI
Pregnancy Can cause fetal harm — increased risk of major congenital malformations (oral clefts) and small-for-gestational-age; dose-dependent; NAAED pregnancy registry
Lactation Excreted in human milk (levels ~ maternal plasma); diarrhea and somnolence reported in breastfed infants; weigh benefit vs risk
NO BOXED WARNINGS
Principal riskCognitive slowing, kidney stones, and fetal oral clefts
Cost, est. cash$5–$150/month
Generic entry2009
Classes and tags
Clinical profile
Legacy pregnancy categoryD
Defining liabilityCognitive slowing, metabolic acidosis, kidney stones, angle-closure glaucoma and teratogenicity.
Mechanism of action: Topiramate ballicule
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Memory aids: mascots and interaction avatars
