Vigabatrin

From Anvita Health Wiki

Contents 1 Introduction 2 Indications 3 Contraindications 4 Dosage 5 Pharmacokinetics 6 Monitor 7 Adverse-effects 8 Drug-interactions 9 Mechanism-of-action 10 More General Terms 11 Internet Database 12 References

Introduction

• Not available in US.

Indications

• complex partial seizures
• neuropathic pain (no randomized, controlled trials)

Contraindications

• Pregnancy category: X

Dosage

• start 1 g PO QD
• adjust by 0.5 mg as tolerated
• maximum dose 4 g/day
• Pediatrics: 40 mg/kg/day, divide BID

• 10-15 kg 0.5-1 g/day 16-30 kg 1-1.5 g/day 31-50 kg 1.5-3 g/day > 50 kg 2-3 g/day

• reduce dosage in elderly

Pharmacokinetics

• rapid absorption, not impaired by food
• mimnal metabolism
• elimination 1/2lif 5-8 hours, up to 13 hours in elderly

• 70% excreted unchanged in the urine

Monitor

• visual field examinations before or soon after starting vigabatrin are recommended, then every 3 months thereafter
  
• monitor with anticonvulsants

Adverse-effects

• > 20%)

• fatigue (27%), headache (26%), drowsiness (22%), visual field defects (33%)

• 10-20%

• dizziness, depression, tremor, agitation, weight gain hyperactivity (pediatrics), other visual disturbances

• 1-10%

• dependent edema, chest pain, amnesia, confusion, paresthesia, impaired concentration, insomnia, anxiety, emotional lability, speech disorder, agression, nervousness, personality disorder,increased appetite, nausea, vomiting, abdominal pain, constipation, ataxia, arthralgia, back pain, abnormal gait, hyporeflexia, nystagmus, diplopia, eye pain, ear pain, nasal congestion, sinusitis

• < 1%

• optic/ retinal atrophy, optic neuritis (generally in 1st year of therapy), angioedema, hallucination, hypersensitivity, hypomania, mania, psychosis, suicide, stupor, urticaria
  

• drug adverse effects of anticonvulsants

Drug-interactions

• vigrabatrin may decrease serum levels of phenobarbital
• igrabatrin may decrease serum levels of phenytoin Herbal interactions:

• evening primrose diminished seizure threshold, valerian, St John's wort, kace gota kula may increase CNS depression

Mechanism-of-action

• increases GABA levels by inhibiting GABA metabolism

More General Terms

• anticonvulsant

Internet Database

PubChem: 5665

References

- UpToDate 13.3 [1] vigabatrin (Sabril)