vigabatrin (Sabril)
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Introduction
Restricted prescribing in U.S. to visual loss.
Indications
- complex partial seizures (generic FDA-approved)[4]
- Lennox-Gastaut syndrome[3]
- neuropathic pain (no randomized, controlled trials)
- infantile spasms[2]
Contraindications
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
- reduce dosage in elderly
* no dosage adjustment in liver failure[3]
Dosage adjustment in renal failure
Pharmacokinetics
- rapid absorption, not impaired by food
- mimnal metabolism
- 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
- > 20%)
- fatigue (27%), headache (26%), drowsiness (22%), visual field defects (33%)*
- 10-20%
- dizziness, depression, tremor, agitation, sedation, weight gain, hyperactivity (pediatrics), other visual disturbances*
- 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
- < 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
- 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
- drug interaction(s) anticonvulsants with anti-bacterial agents
- drug interaction(s) anticonvulsants with statins
Mechanism of action
Notes
More general terms
References
- ↑ UpToDate 13.3 http://www.utdol.com
- ↑ Jump up to: 2.0 2.1 Deprecated Reference
- ↑ Jump up to: 3.0 3.1 3.2 3.3 3.4 Medical Knowledge Self Assessment Program (MKSAP) 16, 17, 18. American College of Physicians, Philadelphia 2012, 2015, 2018
- ↑ Jump up to: 4.0 4.1 4.2 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