Vigabatrin

Vigabatrin is a prescription medication used in combination with other treatments to treat adults with complex partial seizures. Vigabatrin is also used to treat babies with infantile spasms.

Vigabatrin belongs to a group of drugs called anti-epileptics. It works by decreasing abnormal activity in the brain.

This medication comes in tablet and solution form. It is usually taken twice daily with or without food.

Common side effects of vigabatrin include headache, sleepiness, fatigue and dizziness.

This medication may cause drowsiness. Do not drive or operate heavy machinery until you know how vigabatrin affects you.

Vigabatrin is a prescription medication used in combination with other treatments to treat adults with complex partial seizures. Vigabatrin is also used to treat babies with infantile spasms.

This medication may be prescribed for other uses.  Ask your doctor or pharmacist for more information.

Vigabatrin may be found in some form under the following brand names:

• Sabril

Vigabatrin can cause serious side effects. See "Drug Precautions".

These other serious side effects happen in adults. It is not known if these side effects also happen in babies who take vigabatrin.

• Low red blood cell counts (anemia)
• Sleepiness and tiredness
• Nerve problems. Symptoms of a nerve problem can include numbness and tingling in your toes or feet. It is not known if nerve problems will go away after you stop taking vigabatrin.
• Weight gain that happens without swelling
• Swelling

If you are an adult with complex partial seizures, vigabatrin may make certain types of seizures worse. Tell your doctor right away if your seizures get worse.

The most common side effects of vigabatrin in adults include:

• problems walking or feel uncoordinated
• feel dizzy
• shaking (tremor)
• joint pain
• memory problems and not thinking clearly
• eye problems: blurry vision, double vision and eye movements that you cannot control

If you are giving vigabatrin to your baby for infantile spasms:

Vigabatrin may make certain types of seizures worse. You should tell your baby's doctor right away if your baby's seizures get worse. Tell your baby's doctor if you see any changes in your baby's behavior.

The most common side effects of vigabatrin in babies and young children include:

• sleepiness - vigabatrin may cause your baby to be sleepy. Sleepy babies may have a harder time suckling and feeding, or may be irritable.
• ear infection
• irritability

Tell your doctor if you or your baby have any side effect that bother you or that does not go away. These are not all the possible side effects of vigabatrin. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your healthcare provider about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your healthcare provider if you take:

• clonazepam (Klonopin)
• phenytoin (Dilantin, Phenytek)

This is not a complete list of vigabatrin drug interactions. Ask your healthcare provider for more information.

Vigabatrin can cause serious side effects, including:

1. Permanent vision damage
2. Magnetic resonance imaging (MRI) changes
3. Risk of suicidal thoughts or actions

1. Permanent vision damage:

Vigabatrin can damage the vision of anyone who takes it. The most noticeable loss is in your ability to see to the side when you look straight ahead (peripheral vision). If this happens, it will not get better. People who take vigabatrin do not lose all of their vision, but some people can have severe loss particularly to their 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.

• Vision loss and use of vigabatrin in adults: Because of the risk of vision loss, vigabatrin is used to treat complex partial seizures (CPS) only in people who do not respond well enough to several other medicines.

Tell your doctor right away if you:

• think you are not seeing as well as before you started taking vigabatrin
• 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

These changes can mean that you have damage to your vision. Your doctor will test your visual fields (including peripheral vision) and visual acuity (ability to read an eye chart) before you start vigabatrin or within 4 weeks after starting vigabatrin, and at least every 3 months after that until vigabatrin is stopped. You may not be able to be tested in certain situations. Your doctor will determine if you can be tested. Even if your vision seems fine, it is important that you get these regular vision tests because damage can happen to your vision before you notice any changes. These vision tests cannot prevent the vision damage that can happen with vigabatrin, but they do allow you to stop vigabatrin if vision has gotten worse, which usually will lessen further damage. If you do not have these vision tests regularly, your doctor may stop prescribing vigabatrin for you. You should also have a vision test after vigabatrin is stopped. Some people are not able to complete testing of vision for medical reasons. If you cannot complete vision testing, your doctor may continue prescribing vigabatrin, but your doctor will not be able to watch for any vision loss you may get.

If you drive and your vision is damaged by vigabatrin, driving might be more dangerous, or you may not be able to drive safely at all. You should discuss this with your doctor.

• Vision loss in babies: Because of the risk of vision loss, vigabatrin is used in babies (1 month to 2 years old) with infantile spasms (IS) only when you and your doctor decide that the possible benefits of vigabatrin are more important than the risks. Parents or caregivers are not likely to recognize the symptoms of vision loss in babies until it is severe. Doctors may not find vision loss in babies until it is severe. It is difficult to test vision in babies, but all babies should have their vision tested before starting vigabatrin or within 4 weeks after starting vigabatrin, and every 3 months after that until vigabatrin is stopped. Your baby should have a vision test after vigabatrin is stopped. Your baby may not be able to be tested in certain situations. Your doctor will determine if your baby can be tested.

Tell your doctor right away if you think that your baby is:

• not seeing as well as before taking vigabatrin
• acting differently than normal

Even if your baby's vision seems fine, it is important to get regular vision tests because damage can happen before your baby acts differently. Even these regular vision exams may not show the damage to your baby's vision before it is serious and permanent. If your baby does not have these vision tests regularly, your doctor may stop prescribing vigabatrin for your baby. If your baby is not able to complete vision testing, your doctor may continue prescribing vigabatrin for your baby. But, your doctor will not be able to watch for vision loss in your baby.

In all people who take vigabatrin:

• You are at risk for vision loss with any amount of vigabatrin
• Your risk of vision loss may be higher the more vigabatrin you take daily and the longer you take it
• It is not possible for your doctor to know when vision loss will happen. It could happen soon after starting vigabatrin or any time during treatment. It may even happen after treatment has stopped.

Because vigabatrin might cause vision loss, it is available to doctors and patients only under a special program called SHARE. As part of the SHARE program, among other things, your doctor will have to test your or your baby's vision frequently while you or your baby are being treated with vigabatrin, and even after you or your baby stops treatment. You also have to agree to be in the SHARE program, and agree to have your or your baby's vision tested regularly. Your doctor will explain the details of the SHARE program to you.

2. Magnetic resonance imaging (MRI) changes:

Brain pictures taken by magnetic resonance imaging (MRI) show changes in some babies after they are given vigabatrin. It is not known if these changes are harmful.

3. Risk of suicidal thoughts or actions:

Like other antiepileptic drugs, vigabatrin may cause suicidal thoughts or actions in a very small number of people, about 1 in 500 people taking it. Call a doctor right away if you have any of these symptoms, especially if they are new, worse, or worry you:

• thoughts about suicide or dying
• attempts to commit suicide
• new or worse depression
• new or worse anxiety
• feeling agitated or restless
• panic attacks
• trouble sleeping (insomnia)
• new or worse irritability
• acting aggressive, being angry, or violent
• acting on dangerous impulses
• an extreme increase in activity and talking (mania)
• other unusual changes in behavior or mood

Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes.

Watch for early symptoms of suicidal thoughts and actions:

• Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings.
• Keep all follow-up visits with your doctor as scheduled.
• Call your doctor between visits as needed, especially if you are worried about symptoms.

Do not stop vigabatrin without first talking to a healthcare provider.

• Stopping vigabatrin suddenly can cause serious problems. Stopping a seizure medicine suddenly can cause seizures that will not stop (status epilepticus) in people who are being treated for seizures.

Vigabatrin can be prescribed only to people who are enrolled in a program called SHARE. Before you or your baby can begin taking vigabatrin, you must read and agree to all of the instructions in the SHARE program.

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of vigabatrin there are no specific foods that you must exclude from your diet when receiving vigabatrin.
 

If you are an adult with CPS, before taking vigabatrin tell your doctor if you have or had:

• depression, mood problems or suicidal thoughts or behavior
• an allergic reaction to vigabatrin, such as hives, itching, or trouble breathing
• any vision problems
• any kidney problems
• low red blood cell counts (anemia)
• any nervous or mental illnesses, such as depression, thoughts of suicide, or attempts at suicide
• any other medical conditions
• are breastfeeding or planning to breastfeed. Vigabatrin can pass into breast milk and may harm your baby. Talk to your healthcare provider about the best way to feed your baby if you take vigabatrin.
• are pregnant or plan to become pregnant. It is not known if vigabatrin will harm your unborn baby. You and your healthcare provider will have to decide if you should take vigabatrin while you are pregnant.

Pregnancy Registry:

If you become pregnant while taking vigabatrin, talk to your healthcare provider about registering with the North American Antiepileptic Drug Pregnancy Registry. You can enroll in this registry by calling 1-888-233-2334. The purpose of this registry is to collect information about the safety of antiepileptic medicine during pregnancy.

Before giving vigabatrin your baby, tell the doctor about all of your baby's medical conditions, including if your baby has or ever had:

• an allergic reaction to vigabatrin, such as hives, itching, or trouble breathing
• any vision problems
• any kidney problems

Tell your doctor about all the medicines you or your baby take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Vigabatrin and other medicines may affect each other causing side effects.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category C. It is not known if vigabatrin will harm your unborn baby. You and your healthcare provider will have to decide if you should take vigabatrin while you are pregnant.

Pregnancy Registry:

If you become pregnant while taking vigabatrin, talk to your healthcare provider about registering with the North American Antiepileptic Drug Pregnancy Registry. You can enroll in this registry by calling 1-888-233-2334. The purpose of this registry is to collect information about the safety of antiepileptic medicine during pregnancy.

Tell your healthcare provider if you are breastfeeding or planning to breastfeed. Vigabatrin can pass into breast milk and may harm your baby. Talk to your healthcare provider about the best way to feed your baby if you take vigabatrin.

If you are an adult with complex partial seizures:

• Your doctor will explain the SHARE Program to you.
• You will receive vigabatrin from a specialty pharmacy.
• Take vigabatrin tablets exactly as prescribed by your doctor. Vigabatrin tablets are usually taken two times each day.
• You may take vigabatrin tablets with or without food.
• Before you start taking vigabatrin, talk to your doctor about what you should do if you miss a dose of vigabatrin.
• Do not stop taking vigabatrin suddenly. This can cause serious problems. Stopping vigabatrin or any seizure medicine suddenly can cause seizures that will not stop (status epilepticus) in people who are being treated for seizures. You should follow your doctor's instructions on how to stop taking vigabatrin.
• Tell your doctor right away about any increase in seizures while you are stopping vigabatrin.
• If vigabatrin does not improve your seizures enough within 3 months, your doctor will stop prescribing vigabatrin for you.
• Do not stop taking vigabatrin without talking to your doctor. If vigabatrin improves your seizures, you and your doctor should talk about whether the benefit of taking vigabatrin is more important than the risk of vision loss, and decide if you will continue to take vigabatrin.

If you are giving vigabatrin to your baby for infantile spasms:

• Your doctor will explain the SHARE program to you.
• You will receive vigabatrin for oral solution from a specialty pharmacy.
• Mix vigabatrin for oral solution and give it to your baby exactly as prescribed by your doctor. Do not stop giving vigabatrin for oral solution to your baby unless your doctor tells you to.
• Vigabatrin for oral solution is usually given two times each day.
• Vigabatrin for oral solution can be given to your baby at the same time as their food, but the powder should not be mixed with their food. Vigabatrin for oral solution powder should be mixed with water only.
• Before your baby starts taking vigabatrin, speak to your baby's doctor about what to do if your baby misses a dose, vomits, spits up, or only takes part of the dose of vigabatrin.
• Stopping vigabatrin suddenly can cause serious problems. Stopping vigabatrin or any seizure medicine suddenly can cause seizures that will not stop. You should follow your doctor's instructions on how to stop giving vigabatrin to your baby. Vigabatrin does not work in all babies. If your baby's seizures do not improve enough within 2 to 4 weeks, the doctor will stop vigabatrin.
• Tell your doctor right away about any increase in your baby's seizures while stopping vigabatrin.

What you should avoid while taking vigabatrin:

Vigabatrin causes sleepiness and tiredness. Adults taking vigabatrin should not drive, operate machinery, or perform any hazardous task, unless you and your doctor have decided that you can do these things safely.

Adults with complex partial seizure: The recommended dose of vigabatrin in adults is 3 g/day (1.5 g twice daily). Your healthcare provider will likely prescribe a low dose to start, and then gradually increase your dose.

Babies with infantile spasms: The recommended starting dose of vigabatrin is 50 mg/kg/day given in two divided doses and can be gradually increased by 25-50 mg/kg/day increments every 3 days up to a maximum of 150 mg/kg/day.

If you take too much vigabatrin call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If vigabatrin is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

• Store vigabatrin tablets and packets at room temperature.
• Keep vigabatrin tablets and powder in the container they come in.
• Keep vigabatrin and all medicines out of the reach of children.

WARNING: VISION LOSS

• Vigabatrin causes permanent vision loss in infants, children and adults. Because assessing vision loss is difficult in children, the frequency and extent of vision loss in infants and children is poorly characterized. For this reason, the data described below is primarily based on the adult experience.
• In adults, vigabatrin causes permanent bilateral concentric visual field constriction in 30 percent or more of patients that ranges in severity from mild to severe, including tunnel vision to within 10 degrees of visual fixation, and can result in disability. In some cases, vigabatrin also can damage the central retina and may decrease visual acuity.
• The onset of vision loss from vigabatrin is unpredictable, and can occur within weeks of starting treatment or sooner, or at any time during treatment, even after months or years.
• The risk of vision loss increases with increasing dose and cumulative exposure, but there is no dose or exposure known to be free of risk of vision loss.
• It is possible that vision loss can worsen despite discontinuing vigabatrin.
• Because of the risk of vision loss, vigabatrin should be withdrawn from patients with infantile spasms who fail to show substantial clinical benefit within 2 to 4 weeks of initiation, or sooner if treatment failure becomes obvious. Patient response to and continued need for vigabatrin should be periodically reassessed.
• In infants and children, vision loss may not be detected until it is severe. Nonetheless, unless a patient is formally exempted from periodic ophthalmologic assessment as documented in the SHARE program, vision should be assessed to the extent possible at baseline (no later than 4 weeks after starting vigabatrin) and at least every 3 months during therapy. Once detected, vision loss due to vigabatrin is not reversible. Vision assessment is also required about 3 to 6 months after the discontinuation of vigabatrin therapy.
• Drug discontinuation should be considered, balancing benefit and risk, if visual loss is documented.
• Symptoms of vision loss from vigabatrin are unlikely to be recognized by the parent or caregiver before vision loss is severe. Vision loss of milder severity, although unrecognized by the caregiver, may still adversely affect function.
• Vigabatrin should not be used in patients with, or at high risk of, other types of irreversible vision loss unless the benefits of treatment clearly outweigh the risks. The interaction of other types of irreversible vision damage with vision damage from vigabatrin has not been well-characterized, but is likely adverse.
• Vigabatrin should not be used with other drugs associated with serious adverse ophthalmic effects such as retinopathy or glaucoma unless the benefits clearly outweigh the risks
• The lowest dose and shortest exposure to vigabatrin should be used that is consistent with clinical objectives
• The possibility that vision loss from vigabatrin may be more common, more severe or have more severe functional consequences in infants and children than in adults cannot be excluded.

Because of the risk of permanent vision loss, vigabatrin is available only through a special restricted distribution program called SHARE, by calling 1-888-45-SHARE. Only prescribers and pharmacies registered with SHARE may prescribe and distribute vigabatrin. In addition, vigabatrin may be dispensed only to patients who are enrolled in and meet all conditions of SHARE.