Vigabatrin

Pronunciation: vye-GA-ba-trin.

Generic name
vigabatrin
Drug class
Antiepileptic medicine (irreversible GABA transaminase inhibitor)
Form
Film-coated tablet (500 mg) and powder/granules for oral solution (500 mg)
Route
Oral
Legal status
Prescription-only, restricted-distribution program required in several markets; initiation restricted to epilepsy/neurology specialists

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia · New Zealand

Australia: Sabril (5) · Full directory

What vigabatrin is and how it works

Vigabatrin is an antiepileptic medicine used in two specific situations: as an add-on treatment for adults and children (2 years and older) with refractory complex partial seizures that have not responded adequately to several other treatments, and as a stand-alone (monotherapy) treatment for infantile spasms (West's syndrome) in infants between 1 month and 2 years old. (1) (2)

Vigabatrin carries a genuine, serious boxed-warning risk of permanent, usually irreversible vision loss -- narrowing of peripheral vision that can progress to tunnel vision -- affecting roughly one-third of patients who take it, with unpredictable timing. Because of this, it can only be started and prescribed by, or in close consultation with, a specialist in epilepsy or neurology, and requires regular, formal eye examinations before and throughout treatment, even though these tests cannot always prevent vision damage. It is only used when the benefits are judged to genuinely outweigh this serious risk, typically after other treatments have not worked well enough.

Mechanism of action: how vigabatrin works

Vigabatrin is an irreversible inhibitor of GABA transaminase, the enzyme responsible for breaking down the inhibitory neurotransmitter GABA. By blocking this enzyme, vigabatrin increases GABA levels in the brain, enhancing inhibitory neurotransmission and reducing seizure activity. (1)

What vigabatrin is used for

Add-on treatment for refractory complex partial seizures

Used together with other antiepileptic medicines in adults and children aged 2 years and older whose complex partial seizures have not been adequately controlled by several other treatments. Not used as a first-choice treatment. (1) (2)

Monotherapy for infantile spasms (West's syndrome)

Used as the sole treatment for infantile spasms in infants aged 1 month to 2 years, when the potential benefit is judged to outweigh the serious vision-loss risk. (1) (5)

Before taking vigabatrin

Do not take / not appropriate for

  • Vigabatrin should not be started or continued without regular formal eye examinations, since this is how the mandatory vision-loss monitoring requirement is fulfilled. (all countries) (1) (2)
  • Do not take vigabatrin if you have a known allergy to vigabatrin or any ingredient in the tablets or oral solution. (United Kingdom, and consistent with regulator sources reviewed for other markets) (2)

Tell your clinician about

  • Any existing eye or vision problems, so a true baseline can be established before starting.
  • Any history of depression, suicidal thoughts, or other mental health conditions.
  • Your kidney function, since dosing is reduced for kidney impairment.
  • Whether you are pregnant, planning pregnancy, or breastfeeding.
  • All other medicines you take, particularly other antiepileptic medicines.
  • Whether you will be able to attend regular eye examinations, since this is a condition of safe treatment, not an optional add-on.
(1) (2)

How to take vigabatrin

  • Vigabatrin must be started and monitored by, or in close consultation with, a specialist in epilepsy, neurology, or paediatric neurology.
  • Take exactly as prescribed, at the dose your specialist has set for your specific condition -- doses are individualised and increased gradually.
  • You will need a baseline formal eye examination before starting, and repeated eye examinations at regular intervals throughout treatment (and for some months after stopping) -- these are a required part of safe treatment, not optional.
  • Do not stop taking vigabatrin suddenly without your specialist's guidance -- stopping abruptly can cause seizures to return or worsen; your dose will usually be reduced gradually if treatment is stopped.
  • If substantial benefit is not seen within the expected timeframe (around 3 months for complex partial seizures, or 2-4 weeks for infantile spasms), your specialist will reassess whether to continue.
(1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6)

Missed dose

Contact your specialist or pharmacist for guidance if a dose is missed rather than doubling up -- vigabatrin dosing is individualised and abrupt changes to your schedule should be discussed with your care team.

Overdose

Seek urgent medical attention for a suspected overdose. Reported effects of excessive vigabatrin include increased drowsiness, confusion, agitation, or worsening coordination. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Drowsiness (somnolence) and fatigue.

What to notice: Drowsiness (somnolence) and fatigue.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)

Dizziness, headache, and problems with coordination or speech.

What to notice: Dizziness, headache, and problems with coordination or speech.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)

Weight gain (particularly reported in children).

What to notice: Weight gain (particularly reported in children).

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Serious warnings

Signs of vision changes — boxed_warning

Symptoms: Difficulty seeing things to the side (peripheral vision), bumping into objects, needing to turn your head more to see things, or any new vision problem.

Action: Report any vision change to your specialist promptly and keep every scheduled eye examination, even if you feel your vision is fine -- most vigabatrin-related vision loss affects peripheral vision first and can be present without the person noticing. This is a permanent, largely irreversible risk being actively monitored for, not a symptom to wait out. (1) (2)

Signs of a serious skin reaction — emergency

Symptoms: Widespread rash, blistering or peeling skin, or sores in the mouth, especially with fever.

Action: Seek emergency medical help immediately -- rare but serious skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis) have been reported. (1)

New or worsening thoughts of self-harm or suicide — high caution

Symptoms: New or worsening depression, unusual changes in mood or behaviour, or thoughts of harming yourself.

Action: Contact your clinician promptly, or seek emergency help if there is any immediate risk -- this risk is shared across antiepileptic medicines as a class. (1)

New or unusual movement problems in infants treated for infantile spasms — high caution

Symptoms: Unusual, involuntary movements, or excessive sleepiness, confusion, or stupor.

Action: Contact your specialist promptly -- brain imaging changes and movement disorders have been reported in infants, particularly with higher doses; your specialist will decide whether treatment needs to change. (1) (5)

Seizures returning or worsening after stopping — moderate caution

Symptoms: Seizures returning or increasing in frequency after a dose reduction or stopping vigabatrin.

Action: Contact your specialist -- vigabatrin should be withdrawn gradually under specialist guidance, not stopped abruptly, to reduce the risk of rebound seizures. (2)

Interactions

  • Vigabatrin can reduce blood levels of another antiepileptic medicine, phenytoin, over time -- your specialist will monitor for this and adjust treatment as needed. (1)
  • Other medicines that cause drowsiness may add to vigabatrin's sedative effects. (2)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Vigabatrin should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus; discuss with your specialist, since uncontrolled seizures also carry risks in pregnancy. (1) (2) (3) (4) (5) (6)

Breastfeeding

Discuss with your clinician; vigabatrin passes into breast milk. (1) (2) (3) (4) (5) (6)

Children

Approved for infantile spasms monotherapy (1 month to 2 years) and as add-on treatment for refractory complex partial seizures in children 2 years and older, at weight-based doses; the possibility that vision loss may be more common or more severe in infants/children than in adults cannot be excluded. (1) (2) (3) (4) (5) (6)

Elderly

No specific age-based dose recommendation beyond the general dosing described in this page; kidney function (which commonly declines with age) affects dosing. (1) (2) (3) (4) (5) (6)

Hepatic_impairment

Not specifically quantified in the sources reviewed for this dossier. (1) (2) (3) (4) (5) (6)

Renal_impairment

Dose reduction required and increases with the degree of impairment -- approximately 25% lower for mild impairment, 50% lower for moderate impairment, 75% lower for severe impairment; caution advised when creatinine clearance is below 60 mL/min. (1) (2) (3) (4) (5) (6)

Monitoring

Before starting

  • Baseline formal eye examination (visual field testing), ideally within about 4 weeks of the first dose
  • Review of mental health history (depression, suicidal ideation)
  • Kidney function
  • Confirmation that other treatments have not adequately controlled seizures (for the complex partial seizures indication)

During treatment

  • Repeated formal eye examinations at regular intervals (about every 3 months per the US label, every 3-6 months per the UK label) for as long as treatment continues.
  • Continued eye monitoring for some months after stopping vigabatrin, since vision loss risk can persist after discontinuation.
  • Monitoring for mood changes or suicidal ideation.
  • In infants treated for infantile spasms, monitoring for unusual movements or brain-imaging changes, particularly at higher doses.
(1) (2)

Storage

Store at room temperature as directed on the product label, protected from moisture, out of reach of children.

Study the drug class: Antiepileptics

Professional information

Clinician-facing context only, sourced from the current US FDA and UK SmPC labels reviewed for this dossier; verify against the current full label and local restricted-distribution program requirements before prescribing.

United States

Indication: Refractory complex partial seizures (adjunctive, adults)

Dose summary: Start 1000 mg/day (500 mg twice daily); increase weekly by 500 mg to a recommended 3000 mg/day; dispensing restricted to the Vigabatrin REMS Program.

Renal context: Dose reduced 25%/50%/75% for mild/moderate/severe renal impairment respectively. (1)

United Kingdom

Indication: Refractory partial epilepsy (combination) and infantile spasms (monotherapy)

Dose summary: Adults: 1 g/day starting dose, titrated by 0.5 g weekly to a usual 2-3 g/day (maximum 3 g/day); infantile spasms: 50 mg/kg/day starting dose, up to 150 mg/kg/day in some cases; specialist-only initiation.

Renal context: Caution and possible dose/frequency adjustment if creatinine clearance is below 60 mL/min. (2)

Mechanism of action

Hepatic guidance

Not specifically quantified in the sources reviewed for this dossier.

Overdose note

No specific antidote; manage with supportive care, given the risk of increased sedation and confusion. (1)

Frequently asked questions

Why does vigabatrin have a boxed warning?

Because it carries a genuine, serious risk of permanent, largely irreversible vision loss -- specifically a narrowing of peripheral (side) vision that can progress to tunnel vision -- affecting roughly one-third of people who take it. There is no dose known to be free of this risk, and its onset is unpredictable, which is why regular formal eye examinations are a required, not optional, part of treatment. (1) (2)

If I have regular eye tests, will that prevent vision loss from vigabatrin?

Not necessarily. Regular eye examinations are required and important because they can detect vision changes, often before you would notice them yourself, but they cannot always prevent vision damage from occurring in the first place. Vigabatrin is only used when a specialist judges that the treatment benefit outweighs this serious risk. (1)

Why can only a specialist prescribe vigabatrin?

Because of the seriousness of the vision-loss risk and the need for careful patient selection, dosing, and monitoring, vigabatrin can only be started and followed up by, or in close consultation with, a specialist in epilepsy, neurology, or paediatric neurology, and in several countries is only available through a restricted distribution program (such as the US Vigabatrin REMS Program or Canada's SHARE Program). (2) (4)

What is the mechanism of action of vigabatrin?

Vigabatrin is an irreversible inhibitor of GABA transaminase, the enzyme responsible for breaking down the inhibitory neurotransmitter GABA. By blocking this enzyme, vigabatrin increases GABA levels in the brain, enhancing inhibitory neurotransmission and reducing seizure activity. (1)

What is the generic name of Vigabatrin?

The generic name is vigabatrin. (1) (2)

What class of drug is vigabatrin?

Vigabatrin is classed as: Antiepileptic medicine (irreversible GABA transaminase inhibitor). (1) (2)

References

  1. SABRIL (vigabatrin) tablets, for oral use / SABRIL (vigabatrin) for oral solution -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information, Lundbeck Pharmaceuticals LLC · United States · accessed 2026-07-30 · source 1
  2. Sabril 500 mg film-coated tablets -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom · United Kingdom · accessed 2026-07-30 · source 2
  3. Vigabatrin -- EMA 1999 safety review; Kigabeq (vigabatrin hybrid, Sabril as reference medicine) EPAREuropean Medicines Agency (EMA); European Commission-authorised centrally for the related Kigabeq hybrid product · European Union · accessed 2026-07-30 · source 3
  4. SABRIL (vigabatrin) -- Health Canada Product MonographHealth Canada product monograph, Lundbeck Canada Inc. · Canada · accessed 2026-07-30 · source 4
  5. SABRIL vigabatrin 500 mg tablet blister pack -- ARTG entry 150021Therapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-30 · source 5
  6. SABRIL (vigabatrin) tablets / oral solution -- New Zealand Data SheetMedsafe (New Zealand Medicines and Medical Devices Safety Authority) · New Zealand · accessed 2026-07-30 · source 6

Brand names by country

Single-ingredient vigabatrin names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • VIGADRONE50 mg/mL, 500 mg · upsher-smith laboratories, llc
  • SABRIL500 mg, 50 mg/mL · lundbeck pharmaceuticals llc
  • VIGAFYDE100 mg/mL · upsher-smith laboratories, llc

United Kingdom

  • Sabril (2)MHRA licensed emc smpc confirmed · 500 mg tablet, 500 mg granules for oral solution · not fully specified in source

Canada

  • SABRIL

Australia

  • Sabril (5)TGA ARTG registered 2008-05-12 confirmed PBS status unconfirmed · 500 mg tablet, 500 mg powder for oral solution · Sanofi-Aventis Australia Pty Ltd

New Zealand

  • Sabril (6)Medsafe data sheet confirmed · not fully specified in source · not specified in source
View brands in additional countries.

European Union

Sabril (plus Kigabeq, a related hybrid product) (3)

This page provides general reference information about vigabatrin and is not a substitute for advice from the specialist managing your treatment. All dosing, monitoring, and discontinuation decisions should be made with your epilepsy/neurology specialist -- never adjust or stop this medicine on your own, and never skip a scheduled eye examination.

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