Topiramate - Uses, Side Effects, and More

What are the most common side effects of topiramate?

The most common side effects of topiramate are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

• Numbness, tingling, or burning in your arms, feet, or face
• Decreased appetite or weight loss
• Nausea or diarrhea
• Changes in mood, feeling nervous, or anxious
• Concentration, memory, or speech problems (see below)
• Feeling unusually weak or tired 
• Changes in taste
• Dizziness or problems with balance
• Eye problems (see below)

There may be other side effects of topiramate that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of topiramate?

While less common, the most serious side effects of topiramate are described below, along with what to do if they happen.

Severe Allergic Reactions. Topiramate may cause allergic reactions, which can be serious. Stop taking topiramate and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching, skin rash, or pale red bumps on the skin called hives
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Eye Problems and Glaucoma. Topiramate may make it harder to see faraway objects (short-sightedness) or cause other problems seeing. It also may increase pressure inside the eye and cause or worsen narrow-angle glaucoma, which can lead to blindness. Tell your healthcare provider right away if you have any of the following symptoms.

• Trouble seeing faraway objects
• Loss of vision, double vision, or blurred vision
• Eye pain, discomfort, or redness
• Severe headache or vomiting
• Seeing flashes of light or bright, colorful circles around lights (vision halos)

Decreased Sweating and Increased Body Temperature. Tell your healthcare provider right away if you notice that you are sweating less or if you develop a fever, especially in hot weather. Some people may need to be treated in a hospital if this happens.

Metabolic Acidosis. Topiramate can cause a condition called metabolic acidosis. This happens when there is too much acid in the blood. If this condition is not treated, it can cause kidney stones, slowed growth in children, soft or brittle bones (osteopenia, osteomalacia [rickets], or osteoporosis) or harm your unborn baby if you are pregnant. Tell your healthcare provider right away if you have any of the following symptoms of metabolic acidosis.

• Fast breathing or heartbeat
• Headache
• Feeling confused, weak, or tired
• Not feeling hungry
• Nausea or vomiting

Suicidal Thoughts and Actions. Topiramate may increase the risk of suicidal thoughts or actions in a small number of people. If you or your child is about to harm themselves, call 911 or call or text 988, the Suicide & Crisis Lifeline. Call your healthcare provider right away if you have any of the following symptoms.

• New or increased thoughts of suicide or death
• Suicide attempt
• New or increased feelings of anxiety, depression, or other unusual changes in mood or behavior

Concentration, Memory, or Speech Problems. Topiramate can cause changes to your alertness or coordination, concentration, memory, or speech. Do not drive or do other activities that require alertness or coordination until you know how topiramate affects you. Contact your healthcare provider right away if you have trouble concentrating or paying attention, memory problems, confusion, or difficulty finding words.

Weak Bones. Using topiramate for a long time may cause the bones to become weaker, leading to reduced bone density (osteopenia). It may also cause a more serious condition called osteoporosis, which can cause bones to break (fracture) more easily. If you use topiramate, your healthcare provider may monitor your bone density.

Severe Skin Reactions. Topiramate can cause severe skin reactions called Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) that can lead to death if not treated. Get emergency help right away at the first sign of a rash or if you have any of the following symptoms of SJS or TEN.

• Painful red or purple skin that looks burned and peels off
• Flat red rash or blisters on your skin, mouth, nose, and genitals
• Red, painful, watery eyes

High Blood Ammonia Levels. Topiramate can increase ammonia levels in your blood. You may need a blood test to check the amount of ammonia in your blood. Tell your healthcare provider right away if you develop nausea, vomiting, unexplained tiredness, confusion, slowed thinking, or slowed reaction time. 

Kidney Stones. Topiramate may cause kidney stones. You may be more likely to develop kidney stones if you are on a ketogenic diet. Drinking plenty of water can help prevent kidney stones. Tell your healthcare provider right away if you develop severe pain in your side or back, or have blood in your urine (pee). Your pee may look pink, red, or brown.

Growth Problems in Children. Topiramate can slow down how fast your child grows. This risk may be increased in children who get metabolic acidosis (see above). Your healthcare provider may change your child’s dose of topiramate or stop treatment if they are not growing as expected.