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Anticonvulsant (Multiple Mechanisms)

Topiramate

Brand names: Topamax

Used in: Headache & Migraine

Topiramate is used for epilepsy (focal and generalised seizures) and for migraine prophylaxis.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

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) 2.1 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. The dose should be achieved by titration according to the following schedule (Table 1): Table 1: Monotherapy Titration Schedule for Adults and Pediatric …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-06-08. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It has multiple actions — sodium-channel blockade, enhancement of GABA, and carbonic-anhydrase inhibition — that together reduce neuronal excitability.

Prescribing in practice

  • It is teratogenic (cleft lip/palate and reduced fetal growth) and is subject to MHRA restrictions in those able to become pregnant — use highly effective contraception, and it reduces the efficacy of hormonal contraception at higher doses.
  • Cognitive effects (word-finding difficulty, slowing), weight loss, paraesthesia, renal stones, metabolic acidosis and acute glaucoma can occur.
  • Titrate slowly and do not stop abruptly; maintain hydration to reduce stone risk.

Monitoring

Review seizure/migraine control, weight, cognition and mood; in those able to become pregnant confirm pregnancy-prevention measures.

Counselling the patient

  • If you can become pregnant, use highly effective contraception and seek advice before any pregnancy.
  • Report tingling, eye pain or blurred vision, or loin pain (possible kidney stone).
  • Drink plenty of fluids; do not stop it suddenly.

Evidence & guidelines

Used for epilepsy and migraine prophylaxis (NICE NG217/NG150), with MHRA pregnancy-prevention requirements.

Reference: MHRA Topiramate Safety Review 2023; NICE NG217; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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