About Infantile Spasms

Infantile spasms (also called IS or sometimes West syndrome) is a specific type of epilepsy syndrome that affects babies.1

Click the links below to learn more about infantile spasms:

Symptoms of Infantile Spasms

Below is a 3 minute video showing Hudson, a baby with IS, experiencing a "cluster" of spasms. This footage was captured by Wendi, his mom, in order to provide evidence of these spasms to their doctor to help reach a diagnosis. It can be difficult to diagnose IS because the spasms may be subtle at times and, as such, may not be recognized as seizures.1 They can also be misinterpreted as "normal baby movements." When Hudson reaches his arms out wide and looks up, he is experiencing a spasm at that time.

Video of Baby Hudson Experiencing Infantile Spasms

Symptoms of Infantile Spasms

Infantile spasms usually begin when a baby is between 4 and 8 months old.1

There are 3 main features of IS used to aid in diagnosis:1-4

  • Spasms. A baby may suddenly bend forward; stiffen his or her body, arms, and legs; and arch his or her torso (bend backward)
  • Hypsarrhythmia (hyp'sar•rhyth'mia'). An abnormal pattern of electrical activity seen on an EEG between seizures that is associated with IS. It shows chaotic and random electrical behavior in the brain
  • Delayed development. A baby may not develop as expected of his or her age.5 A baby’s development is complex and may be affected by certain causes, known or unknown

Sabril (vigabatrin) therapy has not been proven to improve an infant’s development.

A baby does not have to have all 3 features to receive a diagnosis of IS.5 The term infantile spasms is used to describe both the type of epilepsy and the seizure.5 Most spasms last 1 to 2 seconds. They often happen in groups (or clusters) of a few to more than 100 spasms. A baby may have up to 60 clusters of spasms each day. They may happen when the baby is waking up, or when the baby is sleepy. At first, the spasms may be so small and slight that they are hard to notice.2,3,5

Causes of Infantile Spasms

Sometimes the cause of IS is unknown (cryptogenic). In 3 out of 10 babies with IS, the cause is unknown. About 7 out of 10 babies have IS with a known cause (symptomatic).1

Some of the possible causes include:1,6

  • Tuberous sclerosis complex
  • Central nervous system infection
  • Genetic abnormalities other than tuberous sclerosis complex
  • Brain development abnormalities
  • Lack of oxygen at birth

Sabril and Infantile Spasms

SABRIL (vigabatrin) is a prescription medicine used in babies, 1 month to 2 years old, with infantile spasms (IS), if the possible benefits outweigh the possible risk of vision loss.

Sabril can permanently damage the vision of anyone who takes it. The most noticeable loss is in the ability to see to the side when looking straight ahead (peripheral vision). If this happens, it will not get better. People who take SABRIL do not lose all of their vision, but some people can have severe loss and may only be able to see things straight in front of them (sometimes called "tunnel vision"), and they may also have blurry vision.

After Your Baby Is Prescribed Sabril

  • Your doctor will explain the SHAREPlus program to you
  • You will receive Sabril from a specialty pharmacy
  • Track your baby's response to Sabril
  • Plan vision tests for your baby
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SABRIL ® (vigabatrin) Tablets and Powder for Oral Solution


SABRIL (vigabatrin) is a prescription medicine used with other treatments in adults and children 10 years of age and older with refractory complex partial seizures (CPS) who have not responded well enough to several other treatments and if the possible benefits outweigh the risk of vision loss. SABRIL should not be the first medicine used to treat CPS.

SABRIL (vigabatrin) is a prescription medicine used in babies, 1month to 2 years old, with infantile spasms (IS), if the possible benefits outweigh the possible risk of vision loss.

Important Safety Information

See Medication Guide and full Prescribing Information for complete information.

All people who take SABRIL:
  • You are at risk for vision loss with any amount of SABRIL.
  • Your risk of vision loss may be higher the more SABRIL you take daily and the longer you take it.
  • It is not possible for your healthcare provider to know when vision loss will happen. It could happen soon after starting SABRIL or any time during treatment. It may even happen after treatment has stopped.
  • Because SABRIL might cause permanent vision loss, it is available to healthcare providers and patients only under a special program called the SABRIL Risk Evaluation and Mitigation Strategy (REMS) Program. Your healthcare provider will explain the details of this Program to you.
  • SABRIL can damage the vision of anyone who takes it. People who take SABRIL do not lose all of their vision, but some people can have severe loss particularly to their ability to see to the side when looking straight ahead (peripheral vision). With severe vision loss, you may only be able to see things straight in front of you (sometimes called “tunnel vision”). You may also have blurry vision. If this happens, it will not get better.
  • Tell your healthcare provider right away if you (or your child): might not be seeing as well as before starting SABRIL; start to trip, bump into things, or are more clumsy than usual; are surprised by people or things coming in front of you that seem to come out of nowhere; or if your baby is acting differently than normal. These changes can mean that vision damage has occurred.
  • It is recommended that your healthcare provider test your (or your child’s) vision before or within 4 weeks after starting SABRIL, and at least every 3 months during treatment until SABRIL is stopped. It is also recommended that vision be tested about 3 to 6 months after SABRIL is stopped. It is difficult to test vision in babies, but to the extent possible, all babies should have their vision tested. Your healthcare provider will determine if testing can be done. Regular vision testing is important because damage can happen before any changes are noticed.
  • Vision tests cannot prevent the vision damage that can happen with SABRIL, but they do allow SABRIL to be stopped if vision has gotten worse, which usually will lessen further damage. Even these regular vision tests may not show vision damage before it is serious and permanent. Parents, caregivers, and healthcare providers may not recognize the symptoms, or find vision loss in babies, until it is severe.
  • If vision tests are not done regularly, your healthcare provider may stop prescribing SABRIL for you (or your child). Some people are not able to complete vision testing. If vision testing cannot be done, your healthcare provider may continue prescribing SABRIL, but will not be able to watch for any vision loss.
  • Brain pictures taken by magnetic resonance imaging (MRI) show changes in some babies after they are given SABRIL. It is not known if these changes are harmful.
  • Like other antiepileptic drugs, SABRIL may cause suicidal thoughts and actions in some people. Call a healthcare provider right away if you (or your child) have any symptoms, especially sudden changes in mood, behaviors, thoughts or feelings, and especially if they are new, worse, or worry you.
  • Do not stop SABRIL without first talking to a healthcare provider. Stopping SABRIL suddenly can cause seizures that will not stop.
  • SABRIL can cause serious side effects such as low red blood cell counts (anemia), sleepiness and tiredness, nerve problems, weight gain, and swelling. Because SABRIL causes sleepiness and tiredness, do not drive, operate machinery, or perform any hazardous task, unless it is decided that these things can be done safely. SABRIL may make certain types of seizures worse. Tell your healthcare provider right away if seizures get worse.
  • Before starting SABRIL, tell your doctor about all of your (or your child’s) medical conditions including depression, mood problems, suicidal thoughts or behavior, any allergic reaction to SABRIL, vision problems, kidney problems, low red blood cell counts (anemia), and any nervous or mental illness. Tell your doctor about all the medicines you (or your child) take.
  • If you are breastfeeding or plan to breastfeed, SABRIL can pass into breast milk and may harm your baby. If you are pregnant or plan to become pregnant, it is not known if SABRIL will harm your unborn baby. You and your healthcare provider will have to decide if you should take SABRIL while you are pregnant.
  • The most common side effects of SABRIL in adults include: problems walking or feeling uncoordinated, feeling dizzy, shaking (tremor), joint pain, memory problems and not thinking clearly, and eye problems like blurry vision, double vision, and eye movements that cannot be controlled. The most common side effects of SABRIL in children 10 to 16 years of age include weight gain, upper respiratory tract infection, tiredeness, and aggression. Also expect side effects like those seen in adults.
  • The most common side effects of SABRIL in babies include: sleepiness—some babies may have a harder time suckling and feeding or may be irritable, swelling in the bronchial tubes (bronchitis), ear infection, and irritability.
  • Tell your healthcare provider if you or your child have any side effect that bothers you or that does not go away. These are not all of the possible side effects of SABRIL. For more information, ask your healthcare provider or pharmacist.

For more information, please see SABRIL Medication Guide, full Prescribing Information including Boxed Warning for risk of permanent vision loss, and Instructions for Use; or call toll-free 1-888-457-4273.

Consulte la Información de prescripción completa de SABRIL, incluido el recuadro de advertencia para conocer los riesgos de pérdida permanente de visión, la Guía del medicamento y las Instrucciones de uso; o llame al número gratuito 1-888-457-4273.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.


  1. Shields WD. Infantile spasms: little seizures, big consequences. Epilepsy Curr. 2006;6(3):63-69.
  2. Infantile spasms/West syndrome. Epilepsy Foundation website. http://epilepsyfoundation.org/about/types/syndromes/infantilespasms.cfm. Accessed February 13, 2014.
  3. National Institute of Neurological Disorders and Stroke. National Institutes of Health. Infantile spasms. http://www.ninds.nih.gov/disorders/infantilespasms/infantilespasms.htm. Updated February 13, 2014. Accessed February 13, 2014.
  4. Shields WD. Diagnosis of infantile spasms, Lennox-Gastaut syndrome, and progressive myoclonic epilepsy. Epilepsia. 2004;45(Suppl 5):2-4.
  5. Glauser TA, Morita DA. Infantile spasm (West syndrome). eMedicine website. http://emedicine.medscape.com/article/1176431-overview. Updated June 21, 2012. Accessed February 13, 2014.
  6. National Institute of Neurological Disorders and Stroke. National Institutes of Health. Tuberous sclerosis. http://www.ninds.nih.gov/disorders/tuberous_sclerosis/tuberous_sclerosis.htm. Updated August 12, 2013. Accessed February 13, 2014.