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vigabatrin (Sabril)
Restricted prescribing in U.S. to visual loss.
Indications:
1) complex partial seizures (generic FDA-approved) [4]
2) Lennox-Gastaut syndrome [3]
3) neuropathic pain (no randomized, controlled trials)
4) infantile spasms [2]
Contraindications:
Pregnancy category: X
Dosage:
1) start 1 g PO QD
2) adjust by 0.5 mg as tolerated
3) maximum dose 4 g/day
4) 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
5) reduce dosage in elderly
* no dosage adjustment in liver failure [3]
Dosage adjustment in renal failure:
- yes
- supplemental dose after dialysis [3]
Pharmacokinetics:
1) rapid absorption, not impaired by food
2) mimnal metabolism
3) elimination 1/2life 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
Adverse effects:
1) > 20%)
- fatigue (27%), headache (26%), drowsiness (22%), visual field defects (33%)*
2) 10-20%
- dizziness, depression, tremor, agitation, sedation, weight gain, hyperactivity (pediatrics), other visual disturbances*
3) 1-10%
- dependent edema, chest pain, amnesia, confusion, peripheral neuropathy, paresthesia, impaired concentration, insomnia, anxiety, emotional lability, speech disorder, aggression, 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
4) < 1%
- optic/retinal atrophy*, optic neuritis (generally in 1st year of therapy), angioedema, hallucination, hypersensitivity, hypomania, mania, psychosis, suicide, stupor, urticaria, rash
* peripheral vision loss may be irreversible [3]
Drug interactions:
1) vigrabatrin may decrease serum levels of phenobarbital
2) 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
Notes:
- 1st generic FDA-approved Jan 2019 [4]
Interactions
drug adverse effects of anticonvulsants
monitor with anticonvulsants
General
anticonvulsant
Database Correlations
PUBCHEM cid=5665
References
- UpToDate 13.3
http://www.utdol.com
- Deprecated Reference
- Medical Knowledge Self Assessment Program (MKSAP) 16, 17, 18.
American College of Physicians, Philadelphia 2012, 2015, 2018
- Brooks M
FDA Clears First Generic Version of Seizure Drug Sabril (Vigabatrin)
Medscape - Jan 16, 2019.
https://www.medscape.com/viewarticle/907809
- FDA News Release. Jan 16, 2019
FDA approves first generic version of Sabril to help treat
seizures in adults and pediatric patients with epilepsy.
https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm629569.htm