What strength do vigabatrin tablets come in?

One strength: a 500 mg film-coated tablet with a score line, supplied in bottles of 100. Generic 500 mg tablets are also available.

Can vigabatrin tablets be split or crushed?

The tablet is scored, but splitting tablets by hand is often uneven, and crushing them raises exposure to the drug for the person doing it. No study has measured how accurately vigabatrin tablets split. If a dose cannot be made from whole tablets, ask the prescriber about the powder instead.

Can babies take vigabatrin tablets?

Babies with infantile spasms are dosed with an oral solution, either mixed powder or the ready-to-use liquid. Tablets are used for refractory complex partial seizures from age 2 and in adults.

Vigabatrin 500 mg Tablets: Uses, Splitting and Dosing

Q: Are vigabatrin tablets the same as the oral solution?

They contain the same medicine. The Sabril label states that bioequivalence has been established between the oral solution and the tablets, so the same mg dose is expected to give the same amount of drug in the body.

Short answer: vigabatrin tablets come in one strength, a scored 500 mg film-coated tablet, in bottles of 100.¹ They are used for refractory complex partial seizures in adults and in children from age 2. Babies with infantile spasms are dosed with an oral solution instead.^1,2

The tablets contain the same medicine as the powder sachets and the ready-to-use liquid. For a side-by-side view of all three forms, see liquid vs powder.

What the tablet is

Strength: 500 mg of vigabatrin.
Tablet: film-coated, with a score line.
Pack: bottles of 100 tablets.¹

Sabril tablets were approved in the US in 2009. Several companies now make generic 500 mg tablets.^3,4 See brands.

Who uses tablets

Tablets suit people whose dose is a multiple of 500 mg and who can swallow a tablet. In practice that is mostly adults and older children with refractory complex partial seizures.

For adults and teenagers 17 and older, the label starts at 500 mg twice a day and works up by 500 mg a week to a recommended 1,500 mg twice a day. That is three tablets per dose.¹ A higher dose of 6,000 mg a day worked no better than 3,000 mg in trials and caused more side effects.^1,5

Vigabatrin can be taken with or without food. Food lowers the peak level but not the total amount absorbed.^1,6

Doses that tablets cannot deliver

Children 2 to 16 years old are dosed by weight. Many of those doses do not land on 500 mg steps. A child of 10 to 15 kg starts at 350 mg a day, which is 175 mg twice a day, and the maintenance dose is 1,050 mg a day.¹ Neither can be made from whole or half tablets, so children are often given the powder for oral solution. The dosage page has the full weight table.

Infants with infantile spasms need doses measured in mg per kg, often well under 500 mg. Those are given as an oral solution: mixed powder or, from 1 month to 2 years, the ready-to-use liquid.^2,6

Tablets and the oral solution are bioequivalent

The Sabril label states: "Bioequivalence has been established between the oral solution and tablet formulations."¹ In plain terms, the same mg dose gives the same amount of drug in the body whether it comes as a tablet or as a solution. That matters when someone moves from solution to tablets as they grow, or the other way round. The mg dose stays the same; the prescriber sets the new number of tablets or mL.

Splitting and crushing tablets

The tablet has a score line, so it can be broken along it.¹ But no study has measured how evenly vigabatrin tablets split, or how much drug a crushed vigabatrin tablet delivers. What we have is evidence about tablets in general:

Splitting is often uneven. A review of 13 studies, including some on seizure medicines, found split tablets were acceptably even only 55% of the time.⁷
Home manipulation misses the dose. When people cut or crushed 10 mg hydrocortisone tablets to make children's doses, first-time users got only 57 to 58% of doses within 20% of the target. Parents and carers did better, at 74%.⁸

These studies were not about vigabatrin, but they describe the same steps.

There is also an exposure question. Vigabatrin is on the NIOSH list of hazardous drugs because of possible harm to pregnancy and development.⁹ NIOSH says that "cutting, crushing, or otherwise manipulating tablets and capsules will increase the potential for exposure of workers," and advises that crushing be avoided and liquids used where possible.¹⁰ That guidance is written for healthcare workers, not families. See safe handling.

If a dose cannot be made from whole tablets, ask the prescriber whether the powder would be a better fit.

Kidney function

Most vigabatrin leaves the body unchanged in the urine. In adults its half-life is about 10.5 hours.¹ When the kidneys work less well, blood levels rise, so the label lowers the dose for people 2 years and older: by 25% at a creatinine clearance of 50 to 80 mL/min, by 50% at 30 to 50 mL/min, and by 75% at 10 to 30 mL/min.¹ The dosage page explains this further. The prescriber makes any adjustment.

Same medicine, same warnings

The form does not change the risks. The tablets carry the same boxed warning about permanent vision loss and are available only through the Vigabatrin REMS.^1,6 If vigabatrin has not clearly helped refractory complex partial seizures within 3 months, the label advises stopping it, with a gradual taper rather than all at once.^1,6

Vigabatrin 500 mg tablets