Vigabatrin can cause permanent vision damage, including loss of peripheral vision and having blurry vision. Although vision loss is possible with any amount of vigabatrin, your risk may be greater with the more vigabatrin that you take daily and the longer you take it. Vision loss can happen at any time during treatment with vigabatrin. Tell your doctor if you have or have ever had any vision problems. If you experience any of the following symptoms, call your doctor immediately: think you are not seeing as well as before 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; blurry vision; double vision; eye movements you can't control; eye pain; and headache. Vision loss is not likely to be noticed in infants before it is severe. Be sure to call your doctor immediately if you think your baby is not seeing as well as before taking vigabatrin or is acting differently than normal.
Vigabatrin is only available through a special program called SHARE. You and your doctor will need to be enrolled in this program before you can receive vigabatrin. You will need to get vigabatrin from a specialty pharmacy that is enrolled in the program. Your doctor will give you more information about the program, will have you sign an enrollment form, and will answer any questions you have about the program and your treatment with vigabatrin.
As part of the SHARE program, an eye doctor will test your vision within 4 weeks of starting vigabatrin, at least every 3 months during treatment, and 3-6 months after stopping treatment. Vision testing is difficult in infants and may not find vision loss before it is severe. Vision tests cannot prevent vision damage but they are important to decrease further damage from occurring by stopping vigabatrin if vision changes are found. Once detected, vision loss is not reversible. It is possible that further damage can occur after stopping vigabatrin.
Also as part of the SHARE program, your doctor will assess your response to and continued need for vigabatrin. This is done within 2-4 weeks of starting treatment in infants and children, within 3 months of starting treatment in adults, and then on a regular basis as needed for all patients. If your doctor determines that vigabatrin is not working for you, then your treatment should be stopped.
Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with vigabatrin and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer's website to obtain the Medication Guide.
Talk to your doctor about the risks of taking vigabatrin.
Why is this medication prescribed?
Vigabatrin tablets are used in combination with other medications to control certain types of seizures in adults whose seizures were not controlled by several other medications. Vigabatrin powder is used to control infantile spasms (a type of seizure that babies and children can have) in babies 1 month to 2 years of age. Vigabatrin is in a class of medications called anticonvulsants. It works by decreasing abnormal electrical activity in the brain.
How should this medicine be used?
Vigabatrin comes as a powder to be mixed with water and as a tablet to take by mouth. It is usually taken twice a day with or without food. Take vigabatrin at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take vigabatrin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Your doctor will probably start you on a low dose of vigabatrin and gradually increase your dose, not more often than once every 3 days for babies receiving the powder mixed with water and once a week for adults taking tablets.
Vigabatrin may help control your condition but will not cure it. Continue to take vigabatrin even if you feel well. Do not stop taking vigabatrin without talking to your doctor. If you suddenly stop taking vigabatrin, your seizures may happen more often. Your doctor will probably decrease your dose gradually, not more often than once every 3-4 days for babies receiving the powder mixed with water and once a week for adults taking tablets. Tell your doctor immediately if your seizures happen more often while you are stopping vigabatrin.
If you are taking the powder, you must mix it with cold or room temperature water immediately before taking it. Do not mix the powder with any other liquid or food. The doctor will tell you how many packets of vigabatrin powder to use and how much water to mix it with. The doctor will also tell you how much of the mixture to take for each dose. Do not use a household spoon to measure your dose. Use the oral syringe that came with the medication. Carefully read the manufacturer's instructions that describe how to mix and take a dose of vigabatrin. Be sure to ask your pharmacist or doctor if you have any questions about how to mix or take this medication.
Talk to the doctor about what to do if your baby vomits, spits up, or only takes part of the dose of vigabatrin.
Other uses for this medicine
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking vigabatrin,
- tell your doctor and pharmacist if you are allergic to vigabatrin, any other medications, or any of the ingredients in vigabatrin tablets or powder. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention either of the following: clonazepam (Klonopin) or phenytoin (Dilantin, Phenytek). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with vigabatrin, so be sure to tell your doctor about all the medications you are taking, even those that do not appear here.
- tell your doctor if you have or have ever had kidney disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking vigabatrin, call your doctor.
- you should know that vigabatrin may make you drowsy or tired. Do not drive a car or operate machinery until you know how this medication affects you. If your vision is damaged by vigabatrin, talk with your doctor about whether or not you can drive safely.
- you should know that your mental health may change in unexpected ways and you may become suicidal (thinking about harming or killing yourself or planning or trying to do so) while you are taking vigabatrin. A small number of adults and children 5 years of age and older (about 1 in 500 people) who took anticonvulsants like vigabatrin to treat various conditions during clinical studies became suicidal during their treatment. Some of these people developed suicidal thoughts and behavior as early as 1 week after they started taking the medication. There is a risk that you may experience changes in your mental health if you take an anticonvulsant medication such as vigabatrin, but there may also be a risk that you will experience changes in your mental health if your condition is not treated. You and your doctor will decide whether the risks of taking an anticonvulsant medication are greater than the risks of not taking the medication. You, your family, or your caregiver should call your doctor right away if you experience any of the following symptoms: panic attacks; agitation or restlessness; new or worsening irritability, anxiety, or depression; acting on dangerous impulses; difficulty falling asleep or staying asleep; aggressive, angry, or violent behavior; mania (frenzied, abnormally excited mood); thinking about or trying to hurt yourself or end your life; or any other unusual changes in behavior or mood. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.
- you should know that in some babies that have taken vigabatrin there were changes in pictures of the brain taken by magnetic resonance imaging (MRI). These changes were not seen in older children or adults. Usually these changes went away when treatment was stopped. It is not known if these changes are harmful.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Vigabatrin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- uncontrollable shaking of a part of the body
- joint or muscle pain
- problems walking or feeling uncoordinated
- memory problems and not thinking clearly
- weight gain
- swelling of the hands, feet, ankles, or lower legs
- pain, burning, or tingling in the hands or feet
- stomach pain
- severely painful cramps during menstrual period
Some side effects can be serious. If you experience any of these symptoms or those listed in the IMPORTANT WARNING or SPECIAL PRECAUTIONS sections, call your doctor immediately:
- pale skin
- fast heartbeat
- difficulty breathing
Vigabatrin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].
What should I know about storage and disposal of this medication?
Keep vigabatrin tablets and vigabatrin powder in the container they came in, tightly closed, and out of reach of children. Store them at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include the following:
- loss of consciousness
What other information should I know?
Keep all appointments with your doctor and eye doctor.
Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking vigabatrin.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.