USMLE

Gabapentin

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

Summary

Gabapentin is a neurologic drug that works by blocking calcium channels and preventing the release of neurotransmitters. This in turn blocks the generation and propagation of action potentials. By blocking the transmission of nerve impulses, gabapentin can be used to treat peripheral neuropathy, especially post-herpetic neuropathy. This blockade of nerve impulses also makes gabapentin useful as a narrow spectrum antiepileptic, used to treat focal or partial seizures. Non-specific side effects of gabapentin use include sedation and ataxia.

Key Points

  • Gabapentin
    • Mechanism
      • Primarily inhibits high-voltage-activated Ca+ channels
        • Inhibits voltage-gated Ca2+ channel via α2δ subunit
      • Originally designed as a GABA analog
        • Hence the name, “GABA-pentin”
    • Clinical Use
      • Peripheral neuropathy (esp. postherpetic neuralgia)
        • Severe pain after episodes of shingles/varicella
        • Used along with pregabalin
      • Partial (focal) seizures
        • Considered a narrow-spectrum anti-epileptic
    • Adverse Effects
      • Sedation, ataxia