Topiramate Risks, Warnings, and Complications

EYE PROBLEMS: Topiramate can cause eye problems such as acute myopia (nearsightedness), secondary angle-closure glaucoma (increased pressure in the eye), and visual field defects. Call your doctor immediately if you develop symptoms such as eye pain, redness, or vision changes. Eye symptoms often appear suddenly, usually about a month after starting topiramate. If you develop eye problems, you will need to stop taking topiramate by gradually lowering the dose. The vision problems are usually temporary and go away once you stop topiramate. 

DECREASED SWEATING AND HIGH BODY TEMPERATURE: Rarely, topiramate can cause reduced sweating and raise your body temperature above normal, leading to overheating. Hot weather can cause this side effect. Risk factors also include taking other medications, for example, anticholinergic agents, that make it difficult to sweat. Children and adolescents are at a higher risk of these complications from topiramate use. Monitor your body temperature when you exercise outdoors. Avoid exercising when it is hot outside. Use a mist fan, stay in the shade, and take frequent sips of water to prevent overheating. Call 911 if you develop symptoms of heat stroke or heat exhaustion, such as dizziness, headache, nausea, and muscle cramps.

METABOLIC ACIDOSIS: Rarely, topiramate can cause metabolic acidosis (decreased serum bicarbonate levels and increased acid levels in the blood). Without treatment, this can increase your risk of calcium phosphate kidney stones and bone fractures. It can also cause poor bone growth In children. Risk factors for metabolic acidosis include kidney problems, severe breathing problems, diarrhea, ketogenic diet, status epilepticus, and certain medications. 

Drink plenty of water to prevent kidney stones. Tell your doctor if you develop symptoms of metabolic acidosis, such as extreme fatigue, loss of appetite, fast and shallow breathing, and an irregular or pounding heartbeat. Keep all your laboratory and medical appointments while on topiramate. Your provider may order regular blood tests to measure acid levels in your blood. If you develop metabolic acidosis, you will need to lower the dose, stop topiramate, or take medications to lower acid levels. Never stop taking topiramate suddenly, as this can increase your risk of seizures. Your healthcare provider will tell you how to lower the dose slowly.

SUICIDAL THOUGHTS AND BEHAVIORS: Taking topiramate can increase the risk of suicidal thoughts and behaviors. This can happen within one week of starting the medicine. The risk is especially high during the first few months of treatment and after dose adjustments. People who take other anticonvulsant medications that also affect mood are at a higher risk of this adverse effect. Call your doctor without delay if you notice worsening depression or unusual changes in mood or behavior. 

COGNITIVE AND NEUROPSYCHIATRIC PROBLEMS: Topiramate can cause slowed thinking, trouble concentrating, memory problems, and confusion, speech problems, and loss of coordination. The risk is higher if you start topiramate at a higher dose or increase the dose too quickly. Do not drive or do any hazardous activities until you know how topiramate affects you. Avoid drinking alcohol while on topiramate, as it can make these side effects worse. 

FETAL TOXICITY: Topiramate can cause serious birth defects and slow growth in an unborn baby if the mother takes it during pregnancy. Your healthcare provider will recommend you stay on some form of contraception to prevent pregnancy while you are on topiramate. However, sometimes topiramate is used during pregnancy if the benefits outweigh the risks to the unborn baby. Pregnant women who are on topiramate are encouraged to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry, which monitors and collects information about maternal and fetal health on antiepileptic medications. 

WITHDRAWAL SEIZURES: In people with a history of seizure disorders, stopping topiramate suddenly can cause worsening seizure control and an increase in seizure frequency. Talk to your doctor before stopping topiramate. They will tell you how to lower your topiramate dose slowly over time.

DECREASED BONE DENSITY: Topamax can result in decreased bone mineral density (osteoporosis) and an increased risk of bone fractures. Children and adolescents are at a higher risk of this adverse effect on bone health. This medicine can also cause slowed growth and decrease a child’s height and weight. Talk to your child’s healthcare provider about the risks versus benefits of giving your child topiramate for seizure control. 

ALLERGIC REACTIONS: Rarely, topiramate can cause a severe skin rash and other serious skin reactions. Call your doctor immediately if these effects occur and you develop a skin rash, hives, itching, blistering, or peeling.

HIGH AMMONIA LEVELS: Topiramate can lead to increased ammonia levels in the blood with or without encephalopathy (changes in the brain). The risk of this happening is higher if you are on a high dose of topiramate or if you also take valproic acid. Tell your doctor immediately if you develop tiredness, confusion, changes in consciousness levels, cognitive function (ability to think), lethargy, or vomiting. 

DRUG DRUG INTERACTIONS: Interactions between topiramate and other medications can result in metabolic acidosis and kidney stones. Drink plenty of fluids while on this medicine. Give your doctor and pharmacist a complete list of your medications before starting topiramate to prevent drug-drug interactions.