Anticonvulsant Medications: Common Drugs and Dosing Principles

Anticonvulsants (antiseizure medications, ASMs) are the mainstay of epilepsy treatment. Most are taken once or twice daily (extended-release formulations available for many). Monotherapy is the goal; combination therapy used if needed.

Commonly Used ASMs (Generic / Brand)

• Levetiracetam (Keppra) – broad spectrum, minimal interactions, renal clearance.
• Lamotrigine (Lamictal) – broad, slow titration (rash/Stevens-Johnson), preferred in pregnancy.
• Valproate (Depakote, Depakene) – broad, teratogenic, weight gain, tremor, thrombocytopenia.
• Carbamazepine (Tegretol) / Oxcarbazepine (Trileptal) – focal/GTC; enzyme inducers (CBZ); hyponatremia (OXC).
• Topiramate (Topamax) – broad, weight loss, cognitive effects, stones, glaucoma.
• Zonisamide (Zonegran) – broad, similar to TPM but less cognitive.
• Lacosamide (Vimpat) – focal/GTC, IV/PO, cardiac monitoring (PR prolongation).
• Perampanel (Fycompa) – focal/GTC, long half-life, behavioral risks.
• Brivaracetam (Briviact) – SV2A, like LEV but more selective, less behavioral.
• Phenytoin (Dilantin) – focal/GTC, zero-order kinetics, gum hyperplasia, teratogen, IV loading.
• Phenobarbital / Primidone (Mysoline) – older, sedation, enzyme induction, tolerance.
• Clonazepam (Klonopin) / Clobazam (Onfi) – benzodiazepines, adjunctive, tolerance.
• Ethosuximide (Zarontin) – absence only.
• Cannabidiol (Epidiolex) – Dravet, LGS, TSC.
• Cenobamate (Xcopri) – focal, broad, cardiac monitoring.
• Fenfluramine (Fintepla) – Dravet, LGS; echocardiogram monitoring.

Dosing Principles

• Start low, go slow – minimize side effects, improve adherence.
• Target therapeutic range (for drugs with monitoring: VPA 50–100 µg/mL, CBZ 4–12, PHT 10–20, PB 15–40, LTG 3–14, LCM 5–10).
• Renal/hepatic adjustment per prescribing info.
• Drug interactions: Enzyme inducers (CBZ, PHT, PB, VPA high dose, PER) ↓ levels of other ASMs, OCs, anticoagulants, etc. Inhibitors (VPA low dose, FBM) ↑ levels.

Newer ≠ Always Better

Newer ASMs (LEV, LTG, LCM, BRV, PER, CEN, CBD) have better side effect profiles and fewer interactions, but older drugs (VPA, CBZ, PB) remain effective and inexpensive. Choice is individualized.