11 Topiramate Side Effects You Should Know About

Topiramate (Topamax, Eprontia) is FDA approved to treat or prevent certain types of seizures in adults and children who are at least 2 years old. It also prevents migraines in adults and children who are 12 and older. Although it can be effective, topiramate does have some risks to be aware of. Here, we’ll review several notable topiramate side effects and how you might manage them.

Topiramate side effects at a glance

Common topiramate side effects are often mild. They usually improve on their own after your body gets used to the medication. These common side effects include:

• “Pins and needles” sensations in the hands and feet

• Tiredness and fatigue

• Dizziness

• Weight loss

• Nervousness

• Mental slowing, including memory problems and trouble remembering words

• Diarrhea

• Nausea and abdominal pain

• Distorted sense of taste

• Blurry or double vision

• Mild bleeding

In rare cases, topiramate can cause more severe side effects as well. These may require immediate medical attention. Some examples are:

• Severe vision problems

• Severe skin rash

• Decreased sweating leading to hyperthermia (very high body temperature)

• Metabolic acidosis (acid-base imbalance)

• Suicidal thoughts and actions

• Weakened bones

• Reduced growth in children

• Kidney stones

• Severe bleeding

Below, we go into more detail about 11 topiramate side effects.

1. ‘Pins and needles’ sensation

Paresthesia is a common topiramate side effect. In fact, it’s cited as a common reason why people stop taking topiramate. 

Paresthesia is the medical term for a “pins and needles” sensation felt in the hands or feet. You might describe it as your foot or hand “falling asleep” after being in one position for too long. Paresthesia is more commonly reported in people taking topiramate for migraines than those taking it for seizures. 

This side effect may get better within a few months. But let your healthcare professional (HCP) know if you have bothersome or persistent paresthesia after starting topiramate. They may suggest a lower topiramate dosage. Or they may recommend medications or other products to relieve paresthesias.

2. Weight loss

Weight loss is a well-known topiramate side effect. In fact, topiramate, combined with another medication called phentermine (Qsymia), is FDA approved for weight loss.

It’s not clear how topiramate causes weight loss. But some research indicates it may lower your appetite, increase your metabolism, and reduce your desire for food.

If your child is taking topiramate, they should have their growth closely monitored. If you’re concerned about weight loss or a loss of appetite with topiramate for you or your child, let your HCP know. They may suggest a medication change. Or they might suggest ways to prevent too much weight loss, like increasing your intake of healthy, high-calorie foods. 

3. Drowsiness and fatigue

Drowsiness and fatigue are some of the most frequently reported topiramate side effects. They’re more common with higher dosages and when you first start taking it. This is why you shouldn’t perform activities that require focus — like driving a car — before knowing how topiramate affects you.

Consider asking your HCP about the extended-release version of topiramate (Trokendi XR, Qudexy XR). It’s only taken once daily, so you may be able to take your doses at night to help avoid feeling tired during the day.

If your drowsiness is extreme or doesn’t go away, contact your HCP. This can be a warning sign of a serious side effect called metabolic acidosis. We’ll discuss this more later.

4. Dizziness

Dizziness is a common side effect of many medications. It’s most likely when you first start taking topiramate or if you have a dosage increase. 

If you’re feeling dizzy, be careful when changing positions. Getting up too quickly from a seated or lying position could cause you to fall. And avoid drinking alcohol, which can worsen dizziness. This side effect usually resolves once your body adjusts to the medication.

5. Confusion, trouble concentrating, and short-term memory loss

Topiramate can also cause cognitive impairment. This can best be described as a mental slowing. It involves symptoms like confusion, memory loss, and problems concentrating. It could also mean having difficulty finding or remembering words — like having the word on the tip of your tongue, but not being able to recall it from memory.

Cognitive impairment tends to be worse with higher dosages of topiramate. It’s also more likely if your dosage is increased too quickly. To help reduce your risk of this side effect, your HCP will likely start you on a low dosage and raise it slowly.

Some research suggests that cognitive impairment from topiramate can be long-lasting, even at low dosages. But many studies indicate that it improves significantly after stopping treatment with topiramate. In rare cases, cognitive impairment may be a sign of high ammonia levels leading to brain problems. So if you notice any change to your mental abilities, discuss it with your HCP. They may want to lower your dosage. If your symptoms become too bothersome, they might suggest an alternative medication.

6. Nervousness

Nervousness can happen with topiramate. This side effect is more likely in people taking it for seizures (versus migraines). Other mood changes, such as aggressiveness, depression, and anxiety, can also occur.

If you notice any unusual mood changes while taking topiramate, let your HCP know. Mood changes are more likely with higher topiramate dosages (especially those that are higher than 400 mg per day). Your HCP may try decreasing your dosage if you experience any mood-related symptoms. Or if the mood changes are severe, they may switch you to another medication entirely.

7. Blurred or double vision

Topiramate can cause several eye-related side effects, including blurry or double vision. In very rare cases, more severe eye problems, including acute angle-closure glaucoma (AACG), can also happen. AACG is a medical emergency. It can sometimes be misdiagnosed as worsening migraines. In this case, a person’s topiramate dosage could be mistakenly increased.

People taking topiramate should have annual eye exams. This can help care teams monitor for AACG and other eye problems. If caught early, most eye problems will resolve after stopping topiramate treatment. So new or worsening eye pain or headaches should be reported to your HCP right away.

8. Diarrhea

Diarrhea is another possible side effect of topiramate. Constipation is also possible, though it’s less likely.

In general, diarrhea from topiramate is mild. You can try temporarily eating a diet of bland foods to manage mild diarrhea. One approach is the BRAT diet, which stands for four foods that are gentle on your stomach: bananas, rice, applesauce, and toast. You should also try to avoid foods that you know upset your stomach. And stay hydrated since diarrhea can cause you to lose fluids.

If your diarrhea doesn’t improve, talk to your HCP. They may recommend over-the-counter (OTC) medications for diarrhea, such as Imodium A-D (loperamide). However, if your symptoms are severe or don’t improve, they may ask you to stop taking topiramate. Or they may look into other possible causes of your diarrhea.

9. Decreased sweating

Sweating is one of the main ways the body cools itself down. But topiramate can decrease the amount of sweat your body makes, which can increase your overall body temperature, leading to hyperthermia. This is a serious medical issue that may require hospitalization.

Decreased sweating with topiramate is more common in children. But it can happen to anyone. If you notice a decrease in sweating, feel hot and can’t cool down, or have a fever, let your HCP know. These symptoms are especially important to look out for during warm weather and while performing physical activity. Depending on your situation, your HCP may want to lower your topiramate dosage or change your medication. But don’t make changes to your medication regimen without your HCP’s OK.

10. Metabolic acidosis

Metabolic acidosis — an acid-base imbalance in the body — is a potentially serious topiramate side effect. In most cases, topiramate only causes mild imbalances. But in rare cases, metabolic acidosis can be life-threatening and require hospital care. Severe symptoms include irregular breathing, vomiting, and confusion. If you believe you’re experiencing symptoms of metabolic acidosis, seek medical care right away.

Metabolic acidosis can happen at any time while taking topiramate. People with certain health conditions, such as kidney disease or severe lung problems, may be at higher risk. And in children, long-term metabolic acidosis can affect their growth.

Your prescriber will likely recommend getting blood tests periodically while taking topiramate. These can help them keep an eye on the acid level of your blood. If your blood work indicates you have metabolic acidosis, you may need a lower topiramate dosage. Or your prescriber may recommend taking a medication or supplement for metabolic acidosis or switching to another medication altogether.

11. Suicidal thoughts and behaviors

All seizure medications, including topiramate, can increase the risk of suicidal thoughts or behaviors. This can occur soon after starting treatment, or at any point while taking topiramate. So if you or your child experience any mood or behavior changes, especially worsening depression, contact your HCP right away.

If you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the National Suicide Prevention Lifeline at 988, or text HOME to 741-741 to reach the Crisis Text Line.

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Written by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Daphne Berryhill, RPh

Daphne Berryhill, RPh, has two decades of experience as a clinical pharmacist. She spent most of her career in the Chicago area practicing in-home infusion.

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