Medicine & USMLE


  1. Valproic Acid (Valproate)
  2. Carbamazepine
  3. Ethosuximide
  4. Gabapentin
  5. Lamotrigine
  6. Levetiracetam
  7. Barbituates (Phenobarbital, Thiopental)
  8. Topiramate
  9. Vigabatrin


Ethosuximide is a drug used to treat absence seizures. It blocks T-type Ca2+ channels in the thalamus, inhibiting the propagation of action potentials that trigger and sustain rhythmic discharge in thalamic neurons. A rare side effect of Ethosuximide is Stevens Johnson Syndrome, which is a life-threatening skin condition characterized by skin burning and peeling. There’s also a few nonspecific side effects of ethosuximide, including dizziness, nausea, fatigue, and headaches.

Key Points

  • Ethosuximide
    • Mechanism
      • Blocks thalamic T-type Ca2+ channels
        • Inhibits the propagation of APs that trigger and sustain rhythmical burst discharges in thalamic neurons
    • Clinical Use
      • Absence seizures (1st line)
    • Adverse Effects
      • Steven-Johnson Syndrome (SJS)
        • Drug-induced severe skin rash that may lead to skin necrosis
      • Fatigue, GI distress, headache, itching (and urticaria)