Kigabeq (Vigabatrin)

Vigabatrin is an antiepileptic agent that acts on the GABAergic pathway to control seizure activity.

• Partial seizures: reduces the frequency of focal seizures when used as adjunct therapy.
• Complex focal seizures: helps control seizure episodes that involve impaired awareness.
• Infantile spasms: used as part of a treatment regimen to decrease spasm frequency in infants.

• Vigabatrin irreversibly inhibits the enzyme GABA transaminase, which is responsible for the catabolism of gamma‑aminobutyric acid (GABA) in the central nervous system. By blocking this enzyme, the drug raises intracellular and extracellular GABA concentrations, enhancing inhibitory neurotransmission and thereby stabilizing neuronal firing that contributes to seizure activity.

Vigabatrin may cause a range of adverse reactions, some of which are more frequently observed than others.

Common Side Effects

• Drowsiness: feeling unusually sleepy or fatigued.
• Dizziness: sensation of light‑headedness or unsteadiness.
• Nausea: mild to moderate stomach upset.
• Headache: persistent or intermittent pain in the head.
• Visual field defects: peripheral vision loss, often detected early.
• Fatigue: reduced energy levels during daily activities.

Serious or Rare Side Effects

• Permanent visual field loss: irreversible peripheral vision impairment.
• Depression or suicidal thoughts: mood changes requiring immediate medical attention.
• Severe skin reactions: such as Stevens‑Johnson syndrome.
• Liver enzyme elevation: indicating possible hepatic stress.
• Hematologic abnormalities: including anemia or leukopenia.

Before initiating therapy with Vigabatrin, several safety considerations should be observed.

• Pregnancy: Category D – risk to the fetus; avoid unless the benefit outweighs the risk.
• Renal impairment: dose may need adjustment; monitor renal function regularly.
• Visual monitoring: baseline and periodic eye examinations are recommended to detect early visual field changes.
• Concomitant CNS depressants: may increase sedation; use with caution.
• Store at ambient temperature: keep below 25 °C, in the original packaging, and protect from moisture.

Vigabatrin can interact with other medicines, affecting its efficacy or safety.

Major Interactions (Avoid)

• Other GABAergic agents: additive central nervous system depression.
• Valproic acid: increased risk of visual field defects.
• Carbamazepine: may reduce vigabatrin plasma concentrations.
• Phenobarbital: may diminish vigabatrin's antiepileptic effect.

Moderate Interactions (Monitor Closely)

• Antidepressants: monitor for mood alterations or worsening depression.
• Oral contraceptives: possible reduction in contraceptive effectiveness.
• Renally excreted drugs: monitor renal function to adjust dosing as needed.