Topamax Side Effects

As of June 30, 2024, the Food and Drug Administration’s Adverse Events Reporting System had over 13,000 reports of adverse reactions among patients taking Topamax. Seizures, headaches, weight loss and nausea were among the most frequently reported side effects. 1,242 reports claimed the drug was ineffective.

Disclaimer: Reports sent to the FDA don’t necessarily mean the drug caused an adverse event. Consult a health care professional before stopping or changing medication.

75% of reported side effects listed in the FAERS database involve serious reactions. However, the data does not establish a definitive relationship between Topamax and the listed side effects.

Many people take Topamax safely with no adverse reactions. However, you should be aware of potential side effects before taking any medication, including Topamax.

Topamax’s prescribing information lists several side effects. When it comes to adults who take Topamax exclusively as an epileptic treatment, the top three side effects are tingling sensations (paresthesia), weight loss and drowsiness.

Additional common side effects include dizziness, anorexia, insomnia and poor memory. These side effects tend to be mild and often resolve on their own. They were also more pronounced at high doses of 400 mg compared to a lower dose of 50 mg.

Upper respiratory infection was the top side effect in children taking Topamax, followed by a tingling sensation on the skin. Researchers recorded higher instances of weight decrease in youth compared to adults.

Topamax may also cause rare but serious side effects such as eye complications, metabolic acidosis and kidney stones. Metabolic acidosis is a buildup of acid in the body that can lead to issues such as kidney damage, coma or death if left untreated.

According to its prescribing information, Topamax can cause significant cognitive side effects, including depression and mood disorders.

Additionally, Topamax can affect your vision and slow your motor skills. This may interfere with your ability to operate a vehicle or heavy machinery.

Some patients also reported suicidal thoughts and behavior when taking the drug. The FDA requires the packaging of most anti-seizure medications, including Topamax, to contain a warning about the possibility of suicidal thoughts.

If you notice any symptoms of these conditions, you should report them to your health care provider immediately.

If necessary, your provider may help you develop a plan for coming off the medication gradually. Because stopping Topamax suddenly can cause seizures, even in people without epilepsy, you should not stop taking the medication without consulting your provider first.

Eye Disorders

Blurred vision, eye pain and trouble seeing are all potential symptoms of serious vision disorders that can occur when taking Topamax. The two vision conditions most associated with Topamax use – acute myopia and glaucoma – can lead to permanent vision loss if left untreated.

Acute myopia is a sudden onset of nearsightedness. Nearsightedness is when someone can see things clearly close up, but items in the distance appear blurry.

Glaucoma results from excess pressure in the eye and may cause gradual vision loss. If glaucoma is caught early, the patient may receive medication to decrease eye pressure. This early intervention may preserve the patient’s vision.

Packaging information recommends discontinuing topiramate to resolve vision problems. If you experience any vision impairment while taking Topamax, speak to your doctor as soon as possible to learn how to reduce your dosage safely.

Risks increase dramatically for patients who take Topamax during pregnancy. The FDA recommends the use of effective contraceptive methods to avoid pregnancy. People planning to become pregnant should discuss the risks with their doctor.

If you become pregnant while on Topamax, you should contact your doctor as soon as possible.

Breastfeeding

Topiramate can pass into breast milk during lactation. However, when it comes to infants breastfed by someone on topiramate, “most babies will not have any side effects,” according to the National Health Service. Though rare, some infants may have increased drowsiness or diarrhea.

Breastfeeding people should discuss these risks with a doctor before taking Topamax.

If you are currently on Topamax and breastfeeding, you tell your doctor if your breastfed infant has trouble feeding or becomes more sleepy or irritable.

Fetal Toxicity and Cleft Palate

Research links Topamax use during pregnancy to an increased rate of cleft lip and palate in unborn children. The FDA issued a safety warning about cleft palate risks in 2011 and required a warning in the prescribing information.

“Cleft lip and cleft palate range from a small notch in the lip to a groove that runs into the roof of the mouth and nose, possibly leading to problems with eating, talking and ear infections,” according to the FDA. “Surgery is often used to close the lip and palate.”

Some patients impacted by this side effect filed Topamax lawsuits. These plaintiffs allege that the manufacturer should have provided a birth defect warning sooner.
Because cleft lip and palate form early during pregnancy, people who may become pregnant should discuss these risks with their medical provider before taking Topamax.

To avoid fetal toxicity, the FDA encourages people who can become pregnant to use effective contraception while taking Topamax.

Other Serious Side Effects

Topamax packaging contains warnings for other serious side effects that can be life-threatening. Two rare but serious side effects include oligohidrosis, which is a decrease in sweat, and hyperthermia, which is a high fever. Pediatric patients taking Topamax are at a higher risk of developing these conditions compared to adults.

Hyperammonemia, another serious side effect, is an excess of ammonia in the blood. It can affect mental abilities, cause fatigue and dampen alertness. It can also lead to brain injury and hypothermia. Patients with certain medical conditions, such as reduced mitochondrial activity, are more likely to develop hyperammonemia.

Editor Lindsay Donaldson contributed to this article.