Sabril (vigabatrin) is a prescription drug used to treat certain types of seizure. Sabril can cause side effects that range from mild to serious. Examples include tremor and permanent vision loss.

Specifically, Sabril is prescribed for certain kinds of seizures when the benefits outweigh the drug’s severe side effect risks. The types of seizures Sabril is used for include:

  • infantile spasms, for which Sabril is given as a single-drug treatment to children ages 1 month to 2 years
  • complex partial seizures, for which Sabril is taken as an add-on medication in people ages 2 years and older who have tried several other drugs that didn’t work

The active ingredient in Sabril is vigabatrin. The drug comes as both an oral tablet and a powder that’s mixed with water to make an oral liquid solution.

Keep reading to learn about the common, mild, and serious side effects Sabril can cause. For a general overview of the drug, including details about its uses, see this article.

Sabril (vigabatrin) has a boxed warning for the risk of permanent vision loss. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Side effects explained” section below.

Some people may experience mild to serious side effects during Sabril treatment. Below are just a few of the more common side effects reported in Sabril studies. Side effects can vary depending on the age of the person during treatment and the condition the drug is being taken to treat.

More common side effects in adults taking Sabril for complex partial seizures include:

More common side effects in children ages 3 to 16 years taking Sabril for complex partial seizures include:

More common side effects in children ages 1 month to 2 years taking Sabril for infantile spasms include:

  • middle ear infection
  • upper respiratory tract infection
  • drowsiness

Mild side effects have been reported with Sabril. A few of these include:

  • dizziness
  • cold- or flu-like symptoms
  • headache
  • shaking or tremor
  • uncoordinated movements
  • nystagmus (uncontrolled, rapid movements of the eyeballs)
  • blurred or double vision
  • edema (fluid swelling in arms, hands, legs, or feet
  • weight gain not related to fluid swelling

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. And do not stop taking Sabril unless your doctor recommends it.

Sabril may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

Serious side effects have been reported with Sabril. These include:

If you develop serious side effects while taking Sabril, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

* To learn more about this side effect, see the “Side effects explained” section below.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you are not in the same household, stay on the phone with them until help arrives.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Sabril, visit Medwatch.

Allergic reaction

For some people, Sabril can cause an allergic reaction. But this side effect wasn’t reported in the drug’s studies.

In general, symptoms of an allergic reaction can be mild or serious. You can learn more about possible symptoms in this article.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should keep taking Sabril.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Sabril, they may have you switch to a different treatment.

Learn more about some of the side effects Sabril may cause.

Boxed warning: Risk of permanent vision loss

Sabril has a boxed warning for the risk of permanent vision loss. A boxed warning is the most serious warning from the FDA. It alerts doctors and patients about drug effects that may be dangerous.

Permanent vision loss is a possible side effect reported in studies of Sabril. Because the vision loss is permanent, the FDA will only allow the prescribing and dispensing of Sabril under a Risk Evaluation and Mitigation Strategy (REMS) program.

You, your doctor, your pharmacist, and your pharmacy must all enroll in the Vigabatrin REMS Program to receive Sabril. You can register by visiting the website or calling 866-244-8175.

Vision loss can occur shortly after starting Sabril, while taking the drug (which can last months to years), or even after stopping it. The potential for vision loss exists regardless of your dosage, but it becomes more likely as the duration of treatment and dosage increase.

Vision loss may cause symptoms such as:

  • blurred vision
  • double vision
  • eye strain or pain
  • difficulty with peripheral vision (seeing out of the corner of your eyes)

Vision loss is difficult to predict or detect in infants and young children. Behaviors and symptoms to watch for include:

  • short attention span
  • holding objects close to the eyes
  • covering or closing one eye
  • squinting or frowning
  • rubbing the eyes or blinking often
  • bumping into furniture or walls
  • difficulty reading, coloring, or doing other detailed activities
  • being startled when people move in front of them

Factors that increase the risk of permanent vision loss with Sabril include taking other drugs that have serious eye side effects, including retinopathy or glaucoma.

What might help

To reduce the risk of vision loss with complex partial seizures, you and your doctor will decide how effective Sabril is within the first 3 months. If Sabril isn’t working to treat your condition, your doctor will gradually reduce your dose until you are off it.

For infants and children taking Sabril for infantile spasms, their doctor will evaluate the drug’s effectiveness within the first 2 to 4 weeks. They’ll wean the child off Sabril if it’s not improving their condition.

The following regular vision checks are recommended for everyone taking Sabril:

  • before or within 4 weeks of starting the drug
  • every 3 months while taking it
  • 3 to 6 months after stopping Sabril

Permanent vision loss is possible even with regular vision checks.

If you’re interested in an alternative to Sabril (vigabatrin) because of the risk of permanent vision loss, notify your doctor immediately. And do not stop taking Sabril without discussing it with them first.

Peripheral neuropathy in adults

Peripheral neuropathy in adults was an uncommon side effect reported in studies of Sabril. This condition may also occur in infants and children, but Sabril studies weren’t designed to verify this in people under the age of 18 years.

Peripheral neuropathy may cause symptoms in your feet and toes, such as:

  • prickling, tingling, or a “pins and needles” sensation
  • burning or sharp stabbing pains
  • numbness
  • weakness
  • inability to feel hot or cold

Factors that can increase the risk of peripheral neuropathy when taking this drug include:

What might help

If you have symptoms of peripheral neuropathy during Sabril treatment, talk with your doctor right away. If Sabril is working for you, your doctor may recommend treating the peripheral neuropathy with physical therapy or prescription drugs.

It was not determined in Sabril studies if peripheral neuropathy was reversible after stopping the drug.

If you have questions about peripheral neuropathy while taking Sabril, talk with your pharmacist or doctor.

Suicidal thoughts and actions

Suicidal thoughts and actions were a rare side effect reported in studies of Sabril and can happen with any medication used to treat seizures. Suicidal thoughts and actions may cause symptoms such as:

  • sudden changes in mood or behavior
  • depression or anxiety
  • irritability, restlessness, or agitation
  • panic attacks
  • insomnia (difficulty sleeping)
  • angry or violent feelings or actions
  • dangerous and impulsive actions
  • periods of excitement, overactivity, and excessive talking
  • thoughts about dying or suicide
  • suicide attempts

Factors that can increase the risk of suicidal thoughts and actions when taking this drug include:

  • history of personal or family mental health problems
  • alcohol or drug use disorder
  • taking other medications that increase the risk of suicidal thoughts and actions

What might help

If you have suicidal thoughts or actions while taking Sabril, contact your doctor right away. Call 911 or seek emergency help through a crisis telephone line if these symptoms seem life threatening. Do not stop taking Sabril unless your doctor recommends it.

Sabril oral tablets and oral liquid solution are used to treat:

  • infantile spasms, for which Sabril is given as a single-drug treatment to children ages 1 month to 2 years
  • complex partial seizures, for which Sabril is taken as an add-on medication in people ages 2 years and older who have tried several other drugs that didn’t work

The following mild side effects were reported more commonly in children than in adults in the drug’s studies.

  • weight gain in the treatment of complex partial seizures
  • upper respiratory tract infection, middle ear infection, and drowsiness in the treatment of infantile spasms

Serious side effects that were reported more commonly in children than in adults in the drug’s studies include:

  • MRI brain abnormalities in infants (indicating possible brain changes)
  • intramyelinic edema (swelling of brain tissue that may lead to death) in infants

For more information about potential side effects of Sabril in children, talk with your child’s doctor or a pharmacist.

Get answers to some frequently asked questions about Sabril’s side effects.

Can Sabril (vigabatrin) cause withdrawal symptoms?

Yes. As with any other seizure medication, suddenly stopping Sabril may trigger seizures as a withdrawal symptom.* Other symptoms of withdrawal include:

If you and your doctor decide you should no longer take Sabril, they may suggest a gradual decrease in dosage. If you’re having problems with this medication and need to stop it immediately, call your doctor for instructions. Do not stop taking Sabril unless your doctor recommends it.

* Withdrawal symptoms are side effects that can happen when you stop taking a drug your body has become dependent on. Dependence is when your body gets used to a drug and needs it for you to function as usual.

What are the side effects of Sabril in older people?

There weren’t enough patients ages 65 and above in Sabril’s studies to determine whether side effects were different in older people. But people ages 65 and above may have increased side effects since their kidneys have a reduced ability to eliminate drugs compared to younger patients.

Side effects that may be more pronounced in older adults include confusion and sedation (drowsiness and decreased alertness).

If you’re concerned about taking Sabril due to your age or kidney function, talk with your doctor or pharmacist.

Keeping track of side effects

During your Sabril treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start a new drug or combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Taking notes and sharing them with your doctor will help them learn more about how Sabril affects you. They can then use this information to adjust your treatment plan if needed.

Below is important information you should consider before taking Sabril.

Boxed warning: Risk of permanent vision loss

Sabril has a boxed warning for the risk of permanent vision loss. A boxed warning is the most serious warning from the FDA. For details, see the “Side effects explained” section above.

Other warnings

Sabril can sometimes cause harmful effects in people with certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Sabril is a good treatment option for you.

Talk with your doctor about your health history before starting Sabril. Be sure to tell them if any of the following factors apply to you:

  • vision problems
  • family or personal history of mental health problems
  • kidney problems
  • anemia
  • previous allergic reaction to Sabril
  • taking other prescription medications, over-the-counter drugs, herbs, vitamins, or nutritional supplements
  • pregnancy
  • breastfeeding

Alcohol and Sabril

There are no known interactions between alcohol and Sabril. But drinking alcohol while taking this drug can worsen side effects such as:

  • uncoordinated movements
  • blurred vision
  • drowsiness
  • peripheral neuropathy

If you have questions about consuming alcohol during Sabril treatment, talk with your doctor or pharmacist.

Pregnancy and breastfeeding with Sabril

Sabril is usually prescribed for someone who’s pregnant or breastfeeding only if the benefits of treatment outweigh the potential risks to the fetus or child.

Pregnancy

Sabril is not safe to take during pregnancy because it can cause harm to a fetus. If you’re pregnant or planning to become pregnant, talk with your doctor about your treatment options.

If you’re able to become pregnant, your doctor may recommend using a form of birth control before and throughout your Sabril treatment.

If you take this drug while pregnant, consider signing up for The North American Antiepileptic Drug Pregnancy Registry by visiting the website or calling 888-233-2334. A pregnancy registry collects information about the safety of certain drugs when used during pregnancy.

Breastfeeding

Sabril is not safe to take while breastfeeding because it may pass into breast milk and harm a child who’s breastfed.

If you and your doctor decide the benefits of breastfeeding while taking Sabril outweigh the risks, watch your child for excessive sleepiness, difficulty sucking, or vision loss. Notify your doctor right away if you observe these side effects.

If you’re breastfeeding or planning to do so, talk with your doctor about your options before starting Sabril.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.