Vigabatrin for infantile spasms

Short answer: vigabatrin is FDA-approved on its own for infantile spasms in babies 1 month to 2 years old.^1,2 For babies whose spasms are caused by tuberous sclerosis complex (TSC), it is the usual first choice. For most other babies, hormonal treatment stops spasms more often than vigabatrin alone.^3,4

Infantile spasms are also called infantile epileptic spasms syndrome. Treatment decisions are made by the baby's neurologist. This page explains what the research shows, so families can follow those decisions and ask good questions.

What the label says

Vigabatrin is approved as monotherapy (the only seizure medicine) for infantile spasms in babies 1 month to 2 years old "for whom the potential benefits outweigh the potential risk of vision loss."¹ The ready-to-use liquid (Vigafyde) and Sabril powder for oral solution both carry this indication.^1,2

The dose depends on weight. It starts at 50 mg/kg/day and can rise to 150 mg/kg/day, split into two doses.¹ See dosage for the full schedule and a calculator.

Every vigabatrin product carries a boxed warning about permanent vision loss and is only available through the Vigabatrin REMS program.¹ See vision loss and REMS.

How well vigabatrin works

Higher doses work better

The main US trial compared a low dose (18 to 36 mg/kg/day) with a high dose (100 to 148 mg/kg/day). 24 of 67 babies on the high dose responded, against 8 of 75 on the low dose. Babies with TSC responded faster.⁵ In the final report, which required a video-EEG (a recording of brain waves) to confirm the spasms had stopped, the rates were 15.9% on the high dose and 7.0% on the low dose. About 23% of responders relapsed later, and most of those (72%) became spasm-free again.⁶

Compared with hormonal treatment

Hormonal treatment means ACTH or oral steroids such as prednisolone. Several studies have compared it with vigabatrin:

• UKISS (2004). In 107 babies without TSC, spasms had stopped by days 13 to 14 in 73% on hormonal treatment and 54% on vigabatrin. Side effects were similar (55% vs 54%).⁷
• UKISS follow-up. By 12 to 14 months, about three in four babies were spasm-free in both groups (75% vs 76%). Babies with no known cause for their spasms had better development scores after hormonal treatment, at 14 months and again at 4 years.^8,9
• US national cohort (2016). In 230 babies at 22 US centers, a lasting response at 3 months was seen in 55% on ACTH, 39% on oral steroids and 36% on vigabatrin.¹⁰
• Guideline-based care (2020). In 115 babies treated under a spasms management guideline, remission at 3 months was 79% with ACTH, 83% with prednisolone and 40% with vigabatrin.¹¹
• Reviews. A Cochrane review of 18 trials found that hormones stop spasms faster and in more babies than vigabatrin, though most trials were of poor quality. It recommends high doses if vigabatrin is used.¹² A 2023 meta-analysis of 5 trials found vigabatrin alone less effective than hormones alone (odds ratio 0.37), but much more effective in TSC than in other causes (odds ratio 5.59).³

• Vigabatrin
• Hormone treatment (ACTH or steroids)

UKISS trial, babies without TSC: spasms stopped by day 14

Hormone treatment

73%

Vigabatrin

54%

US national cohort: lasting response at 3 months

ACTH

55%

Oral steroids

39%

Vigabatrin

36%

Show as a table

Group	Measure	Value
UKISS trial, babies without TSC: spasms stopped by day 14	Hormone treatment	73%
UKISS trial, babies without TSC: spasms stopped by day 14	Vigabatrin	54%
US national cohort: lasting response at 3 months	ACTH	55%
US national cohort: lasting response at 3 months	Oral steroids	39%
US national cohort: lasting response at 3 months	Vigabatrin	36%

Vigabatrin together with hormones

The ICISS trial gave 377 babies either hormonal treatment alone or hormonal treatment plus vigabatrin (at least 100 mg/kg/day). Spasms stopped between days 14 and 42 in 72% on the combination and 57% on hormones alone.¹³ At 18 months, development scores and epilepsy rates were the same in both groups.¹⁴

• Hormones plus vigabatrin
• Hormones alone

Hormones plus vigabatrin

72%

Hormones alone

57%

Development at 18 months was the same in both groups.

Show as a table

Group	Measure	Value
ICISS trial: spasms stopped between days 14 and 42	Hormones plus vigabatrin	72%
ICISS trial: spasms stopped between days 14 and 42	Hormones alone	57%

Babies with tuberous sclerosis

TSC is the clear exception. In a small trial, all 11 babies with TSC given vigabatrin stopped having spasms, against 5 of 11 given hydrocortisone.¹⁵ See vigabatrin for tuberous sclerosis.

Why early response matters

Time matters with infantile spasms. In UKISS, each step up in the delay before effective treatment was linked to a lower development score at age 4.¹⁶ In ICISS, babies whose spasms stopped early had higher development scores at 18 months (79.1 vs 63.2), and a longer delay to treatment was linked to lower scores.¹⁴

Response usually comes fast. In a study of 395 babies, 43% went into remission within 2 weeks, and most of those within the first week. Babies who responded to vigabatrin did so in a median of 3 days. The authors advise reassessing straight away any baby who has not responded after 1 week.¹⁷

What guidelines say

• US consensus (2010): recognize spasms early, start a short course of first-line treatment, use a timely EEG to judge response, and change treatment promptly if it is not working.¹⁸
• International League Against Epilepsy task force (2015): ACTH is preferred for short-term spasm control, oral steroids are probably effective, and a shorter time to treatment may improve outcome.¹⁹
• American Academy of Neurology (2012): found ACTH more effective than vigabatrin in the short term for babies without TSC, and preferred hormones for development when no cause is found. This guideline has since been retired and is of historical interest only.²⁰
• Global review (2026): a review of 28 guidelines from around the world found that every one recommends vigabatrin first for spasms caused by TSC. Recent guidelines increasingly endorse prednisolone and vigabatrin, about a quarter of those since 2017 mention combination treatment, and response is usually judged at about 14 days.⁴

The 2026 American Epilepsy Society guideline on infant epilepsy leaves infantile spasms out on purpose, so it adds no new US advice here.²¹

In practice

• Judging response. Doctors usually decide whether treatment is working within about two weeks, often with an EEG.^4,18
• Stopping if it does not help. The label advises withdrawing vigabatrin if it has not clearly helped within 2 to 4 weeks. It is tapered, not stopped suddenly.^1,22
• Vision checks. A baseline eye exam is due no later than 4 weeks after starting, then at least every 3 months, and again about 3 to 6 months after stopping.¹
• Other effects. Brain MRI changes were seen in 22% of babies on vigabatrin vs 4% on other treatments; drowsiness and weight gain also occur.¹ See side effects.

Which form babies use

Babies with infantile spasms are dosed with an oral solution. That can be powder mixed fresh with water before every dose, or the ready-to-use liquid, which needs no mixing and is labeled only for this group.^1,2 In the one direct comparison, a small study funded by the liquid's maker, caregivers measured the liquid more accurately than doses mixed from powder.²³ See liquid vs powder and powder sachets.

Support for families

These groups support families affected by infantile spasms. This site has no tie to any of them and is not responsible for their content.

• Infantile Spasms Action Network (ISAN)
• Epilepsy Foundation family services
• Infantile Spasms Community on Facebook
• Epilepsy Alliance America support groups
• r/infantilespasms on Reddit