Gabapentin

Name

Class of drug

• Anti-epileptic drug (GABA[gamma-aminobutyric acid] agonist) - analog of GABA.

Uses

Action

• Gabapentin inhibits tonic hindlimb extension in the electroshock seizure model.
• Also inhibits clonic seizures induced by pentylenetetrazol.
• Efficacy in both these tests parallels that of valproic acid and distinguishes it from phenytoin and carbamazepine in humans.
• Despite its design as a GABA agonist, gabapentin does not mimic GABA when iontophoretically applied to neurons in primary culture.
• Does not bind to GABA A or B receptors.
• Appears to act by a novel mechanism; increases promoted release of GABA by an unknown mechanism.
• Has not been found consistently to reduce sustained repetitive firing of action potentials nor to significantly affect any Ca2+ channel current.

Indications

• Adjunctive treatment of generalized seizures that are considered refractory to phenobarbitone and potassium bromide .
• Adjunctive gabapentin therapy will reduce frequency of generalized seizures in over approximately 45% of idiopathic epileptic dogs refractory to phenobarbitone and potassium bromide therapy.
• Adjunctive treatment of partial seizures with or without secondary generalization not satisfactorily controlled with other anti-epileptics .
• Neuropathic pain.

Adverse reactions

Effects of overdosage

• Most common adverse effects are:
  • Somnolence.
  • Dizziness.
  • Ataxia.
  • Fatigue.
• Effects usually are mild to moderately severe but resolve within 2 weeks of onset during continued treatment.
• Overall, well tolerated.

Reporting of reactions

• Severe ataxia.
• Lethargy.

Treatment

• Drug removal.

Antidote for overdose

• None.