If you have epilepsy or migraine, your doctor might suggest Topamax (topiramate) as a treatment option for you. Along with other factors to consider, you may be wondering about the medication’s possible side effects.

Topamax is a prescription medication that’s used in adults and some children to:

Topamax comes as tablets that you swallow and as sprinkle capsules. The sprinkle capsules can be swallowed whole or opened and poured onto food. Topamax is typically used as a long-term treatment.

For more information about Topamax, including details about its uses, see this in-depth article on the drug.

Like other drugs, Topamax can cause mild or serious side effects. Keep reading to learn about certain side effects of the drug and ways for dealing with them.

Below are a few of the more common side effects reported by people who took Topamax in studies. These side effects can vary depending on which condition the drug is being used to treat.

More common side effects in people taking Topamax for migraine include:

More common side effects in people taking Topamax for epilepsy include:

  • tingling in the legs and arms
  • loss of appetite
  • weight loss
  • dizziness
  • sleepiness

Read on to learn about other mild and severe side effects that can happen with Topamax.

You may have mild side effects from Topamax.

Examples of mild side effects that have been reported with Topamax include:

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

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop using Topamax unless your doctor recommends it.

Topamax may cause mild side effects other than the ones listed above. See the Topamax prescribing information for details.

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

Topamax may cause rare but serious side effects.

Serious side effects that have been reported with Topamax include:

If you develop serious side effects while taking Topamax, call your doctor right away. If the side effects seem life threatening or if 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.
† An allergic reaction is possible after using Topamax. But this side effect wasn’t reported in studies.

Topamax is used to treat certain types of epilepsy in children ages 2 years and older, and to prevent migraine headaches in children ages 12 years and older.

Most side effects of Topamax in children are expected to be the same as those in adults. But the following side effects may be more likely to happen in children:

Talk with your child’s doctor about your child’s risk of side effects from Topamax.

In most cases, side effects from Topamax are temporary. Most side effects tend to go away soon after you start or stop taking the drug.

But severe side effects that could lead to long-term problems and permanent damage from Topamax are possible. For example, Topamax may cause eye side effects,* such as glaucoma. And if untreated, glaucoma could cause blindness.

If you have questions about possible long-term side effects of Topamax, talk with your doctor or pharmacist.

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

Below are answers to a few frequently asked questions about Topamax’s side effects.

If I stop taking Topamax, will I be dealing with withdrawal symptoms?

It’s possible. But there haven’t been studies done on Topamax withdrawal. (Withdrawal symptoms are side effects that can happen when you stop taking a drug.)

After you stop taking Topamax, the symptoms you were taking it for may return. So you may have migraine headaches or seizures more often, or they may be more severe. And if you’re taking Topamax for epilepsy, suddenly stopping the drug could cause seizures.

For these reasons, you shouldn’t stop taking Topamax unless your doctor tells you it’s safe to do so. When it’s time for you to stop taking Topamax, your doctor will lower your dosage slowly over time. This lessens your risk of withdrawal symptoms after you stop Topamax.

Can stopping Topamax cause weight gain?

Yes, it’s possible to gain weight after stopping Topamax.

Weight loss is a common side effect of Topamax. If you have weight loss while taking the drug, it’s possible you could gain weight after you stop taking Topamax.

If you’re concerned about weight changes after you start or stop Topamax, talk with your doctor. They can recommend ways to reach or maintain a weight that’s healthy for you.

Does my risk of side effects depend on the strength of Topamax I take (such as 25 mg or 50 mg)?

Yes, the risk of side effects from Topamax can depend on the strength you take.

For example, you may have a higher risk for certain side effects if you take higher doses of Topamax. Examples include:

  • trouble with memory, concentration, or thinking clearly
  • fatigue (low energy)
  • dizziness
  • tingling in your legs and arms
  • mood changes*

If you have more questions about your risk of certain side effects from Topamax, talk with your doctor or pharmacist.

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

Can Topamax cause sexual side effects?

Yes, Topamax may cause sexual side effects, such as decreased sex drive. But these side effects weren’t common in studies of the drug.

Keep in mind that Topamax may cause mood changes,* including depression. And these mood changes could cause sexual side effects. So it may be hard for you to tell if sexual side effects are caused by Topamax itself or by certain mood changes the drug may cause.

If you have sexual side effects while you’re taking Topamax, talk with your doctor. They can help you figure out if you’re having other mood changes that could cause these side effects.

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

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

Hair loss

It’s possible to have hair loss while taking Topamax. In studies, this side effect was more common in people who took the drug to treat epilepsy than to prevent migraine headaches.

What might help

Hair loss from Topamax is generally reversible. Any hair you lose while taking Topamax is expected to grow back after you stop taking the drug.

If you have questions about Topamax and hair loss, talk with your doctor or pharmacist. If you have hair loss that’s bothersome to you, your doctor may prescribe a drug other than Topamax for your condition.

Stomach problems, such as constipation or stomach pain

Topamax can cause certain stomach-related side effects. These may include:

What might help

If you have bothersome stomach problems while taking Topamax, talk with your doctor. They can suggest ways to ease your symptoms.

You can take Topamax with food or without it. But taking the drug with food may help lessen any stomach problems you have.

Eye side effects

Ocular (eye-related) side effects may occur with Topamax. Abnormal vision, double vision, and blurred vision were common in studies of the drug.

Although rare, Topamax can also cause a glaucoma attack. This condition causes sudden, severe eye pain and blurry vision. It can lead to blindness if it’s not treated.

What might help

If you have any eye problems while taking Topamax, tell your doctor right away. They’ll likely give you tests to make sure you aren’t having severe eye problems.

Severe rash and other serious skin reactions

In rare cases, Topamax may cause serious skin reactions. Examples include Stevens-Johnson syndrome and toxic epidermal necrolysis. Symptoms of these conditions may include:

  • severe rash with or without peeling
  • blisters
  • skin discoloration
  • hives (raised, itchy welts)

What might help

Tell your doctor right away or go to the nearest emergency room if you notice any of the above symptoms while you’re taking Topamax. If your symptoms seem life threatening, call 911 or your local emergency number immediately.

Mood changes

Rarely, Topamax may cause mood changes. Examples of mood changes you may notice while taking Topamax include:

What might help

Tell your doctor right away if you have mood changes while taking Topamax. They may prescribe a drug other than Topamax for you.

If you have thoughts of harming yourself while taking Topamax, call 911 or your local emergency number right away.

SUICIDE PREVENTION

If you think someone is at immediate risk of self-harm or hurting another person:

  • Call 911 or your local emergency number.
  • Stay with the person until help arrives.
  • Remove any guns, knives, medications, or other things that may cause harm.
  • Listen, but don’t judge, argue, threaten, or yell.

If you or someone you know is considering suicide, get help from a crisis or suicide prevention hotline. Try the National Suicide Prevention Lifeline at 800-273-8255.

Allergic reaction

Like most drugs, Topamax can cause an allergic reaction in some people. But this side effect wasn’t reported in studies.

Symptoms can be mild or serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

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 medication to manage your symptoms. This may include an over-the-counter antihistamine that you take by mouth, such as Benadryl (diphenhydramine). Or it may include a topical product (that’s applied to your skin), such as hydrocortisone cream.

If your doctor confirms you had a mild allergic reaction to Topamax, they’ll decide whether you should continue taking the drug.

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 had a serious allergic reaction to Topamax, they may have you switch to a different treatment.

Keeping track of side effects

During your Topamax treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

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

Keeping notes and sharing them with your doctor will help your doctor learn more about how Topamax affects you. And your doctor can use this information to adjust your treatment plan if needed.

Topamax may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Topamax. The list below includes factors to consider.

Bone problems. Before taking Topamax, tell your doctor if you have bone problems such as osteoporosis. Topamax can cause a high level of acid in the blood. If this condition isn’t treated, it can lead to osteoporosis. If you have bone problems before starting Topamax treatment, you may have a higher risk of bone problems related to high acid levels. Talk with your doctor to learn if Topamax is right for you.

Frequent diarrhea. Before taking Topamax, tell your doctor if you have diarrhea that’s frequent or hard to manage. Having diarrhea like this could raise the level of acid in your blood, which may increase your risk of a high acid level in your blood as a side effect of Topamax. Your doctor may monitor your acid levels more closely than usual during treatment.

Lung problems. Tell your doctor if you have lung problems before starting Topamax. This includes conditions such as asthma and chronic obstructive pulmonary disease (COPD). These conditions may raise the acid level in your blood. And this could increase the chances of Topamax causing a high level of acid as a side effect. Talk with your doctor to learn if Topamax is right for you.

Mood problems or suicidal thoughts. Topamax may cause mood changes, including suicidal thoughts and behaviors. Before taking Topamax, tell your doctor if you have mood problems such as depression. They’ll advise whether it’s safe for you to take Topamax.

Kidney problems. Before taking Topamax, tell your doctor if you have kidney problems. Kidney problems may increase the level of acid in your blood. This could raise your risk for having a high level of acid as a side effect of Topamax. Your doctor may monitor your acid levels more closely than usual during treatment. They may also prescribe you a dose of Topamax that’s lower than usual.

Liver problems. Tell your doctor if you have liver problems before starting Topamax treatment. Liver problems could raise your risk for a high level of ammonia in your blood, which is a possible side effect of Topamax. Your doctor can recommend whether Topamax is safe for you to take.

Allergic reaction. If you’ve had an allergic reaction to Topamax or any of its ingredients, you shouldn’t take Topamax. Ask your doctor what other medications are better options for you.

Following a ketogenic (“keto”) diet. Before starting Topamax treatment, tell your doctor if you follow a ketogenic diet. This type of diet may raise the level of acid in your blood. And this could increase your risk for having a high level of acid as a side effect of Topamax. Your doctor may suggest a different seizure diet for you while you’re taking Topamax, if needed.

Alcohol use and Topamax

You shouldn’t drink alcohol while you’re taking Topamax. Doing so can worsen certain side effects of Topamax, such as dizziness and sleepiness.

If you have questions about Topamax’s alcohol interaction, talk with your doctor.

Pregnancy and breastfeeding while taking Topamax

Below we provide information about Topamax and pregnancy and breastfeeding.

Topamax and pregnancy

It may not be safe to take Topamax while pregnant. If taken during pregnancy, the drug can cause side effects in children. These can include cleft palate and cleft lip, and being smaller than usual for their age.

If you’re pregnant or planning a pregnancy, talk with your doctor before starting Topamax. They may recommend a different drug for your condition.

If you take Topamax during pregnancy, consider enrolling in the drug’s pregnancy registry. Pregnancy registries collect information about the drug’s effects when used during pregnancy. This helps researchers understand the risks of using Topamax during pregnancy, which can help others make decisions about their treatment.

To enroll in the North American Antiepileptic Drug Pregnancy Registry, visit the registry’s site. Or call 888-233-2334.

Topamax and breastfeeding

It may not be safe to use Topamax while breastfeeding. If taken while breastfeeding, Topamax may pass into breast milk. The drug may also cause a breastfed child to have diarrhea and sleepiness.

Your doctor can talk with you about the risks and benefits of taking Topamax while breastfeeding.

Topamax is used to treat epilepsy and to prevent migraine headaches.

Mild side effects from Topamax are common. But Topamax can also cause serious side effects in some people, especially at higher doses.

If you have questions about side effects from Topamax, talk with your doctor or pharmacist. Below are a few questions you may want to ask:

  • If I have side effects from Topamax, will I need to take a lower dose of the drug?
  • Are there any side effects of Topamax that I should tell you about right away?
  • How should I manage side effects I may have from Topamax?

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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.