Topamax Side Effects

Topamax (topiramate) is an anticonvulsant medication approved by the U.S. Food and Drug Administration in 1996 to treat patients with epilepsy and in 2004 for the prevention of migraines. The drug can cause side effects ranging from loss of appetite and memory issues to serious eye problems, suicidal thoughts or behavior, and birth defects.

Topamax Pills
Topamax Side Effects
  1. Most Common Side Effects Burning or prickling sensation, loss of appetite
  2. Warning & Precuations Drug may cause eye problems, decreased sweating and increased body temperature, increased level of acid in blood, suicidal thoughts or behaviors, harm to unborn babies

Doctors prescribe Topamax (topiramate) for epileptic seizures and migraines because it works to decrease abnormal nerve cell activity. They also frequently prescribe it with other medications to treat Lennox-Gastaut syndrome, a form of childhood-onset epilepsy that causes seizures and developmental delays.

The list of warnings and precautions in the medication guide is extensive, and the drug’s maker has continually updated the safety information since the medicine became available in the United States. The Food and Drug Administration mandated the updates over the years as postmarketing studies continued to confirm the drug’s adverse health effects.

Common Side Effects and Serious Warnings

People with seizure disorders usually take larger doses of Topamax than do people with migraines, and the list of common side effects is more extensive for this group of patients.

The most frequent side effects among people taking the drug for seizures include:
  • Burning or prickling sensation
  • Loss of appetite
  • Weight loss
  • Sleepiness
  • Fatigue
  • Memory problems
  • Insomnia
  • Weakness and lack of energy
  • Dizziness
  • Nervousness
  • Speech or language problems (difficulty finding words)
  • Slowed movement
  • Difficulty concentrating
  • Cognitive problems
  • Confusion
  • Mood problems
  • Fever
  • Infection
  • Flushing
  • Diarrhea

The most common side effects among people taking the drug for migraine include tingling or pins-and-needles sensations, and changes in the way things taste. Some users say that carbonated drinks, in particular, taste bad when they are on the drug.

The drug’s prescribing information advises doctors to warn patients about the potential for extreme tiredness, dizziness, confusion, difficulty concentrating or visual effects. Patients should not drive or operate machinery until they can determine whether the drug adversely affects their mental performance, motor performance and/or vision.

The medication label also warns of more serious side effects that may occur, including vision problems, suicidal behavior and birth defects.

Other serious side effects that can lead to hospitalization, coma and even death include:
Oligohidrosis and hyperthermia
Decreased sweating and dangerously elevated body temperature
Hyperammonemia
Excess of ammonia in the blood, which can affect mental activities, slow alertness and cause fatigue or vomiting
Encephalopathy
A brain disease that alters brain function or structure
Hypothermia
A medical emergency categorized by dangerously low body temperature that occurs when the body loses heat faster than it can produce it
Metabolic acidosis
The body produces too much acid, or the kidneys do not remove enough acid from the body, causing brittle or soft bones, kidney stones, slower rate of growth in children, coma and death

Quitting Topamax suddenly can also bring on seizures. As a result, people should gradually taper off the drug or be closely monitored if they must stop taking it abruptly, according to the drug’s label.

Oral Clefts and Other Birth Defects

Infants exposed to topiramate in utero have an increased risk for cleft lip and cleft palate, especially if the drug is taken during the first trimester of pregnancy. The drug’s label advises doctors to consider the risks and benefits of prescribing the drug to women who can become pregnant.

Surveillance data from the North American Antiepileptic Drug (NAAED) Pregnancy Registry showed 1.4 percent of babies born to women taking Topamax had oral clefts, compared to a prevalence of 0.55 percent or less in infants whose mothers took other anticonvulsant medications.

Additionally, a 2008 study in Neurology journal looked at the UK Epilepsy and Pregnancy Register and found babies born to mothers who took Topamax during pregnancy suffered birth defects at 11 times the average rate.

In March 2011, the FDA issued a warning that Topamax may increase the risk of oral cleft birth defects as much as 21.3 percent based on the data from the pregnancy registries. The FDA also reclassified Topamax as a Class D drug, meaning it has been shown to harm the human fetus.

Newborn with Cleft Lip
According to the Food and Drug Administration, oral clefts develop during the first trimester of pregnancy when many women are unaware they are pregnant.

“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.”

Following the 2011 safety alert, people began filing Topamax lawsuits claiming the manufacturer should have fully informed women of the risk of birth defects but failed to do so despite evidence of increased birth defects available as early as 2008.

Babies born to mothers who take the drug during pregnancy may also suffer from other birth defects, including: limb malformations, heart defects, lung defects and neural tube defects, such as spina bifida. The drug has also been linked to persistent pulmonary hypertension of the newborn (PPHN).

Birth Control, Pregnancy and Breastfeeding

The FDA advises women of childbearing age who decide to take Topamax and who do not plan to become pregnant to use effective birth control. The medication may make birth control less effective, so it is crucial that women who can become pregnant and their doctors know the risks and discuss other treatment options. Women should ask their doctors about the best kind of birth control to use while taking the drug.

Women who become pregnant or who plan to become pregnant should talk to their doctors immediately about whether it’s appropriate to continue taking topiramate. Even if women become pregnant, they should not stop taking the drug unless a doctor instructs them to do so. Discontinuing the medication suddenly can cause serious problems.

It’s important to know that topiramate passes into breast milk, and the effects of exposing infants to the drug remain unknown. Women who are currently breastfeeding should consult their doctor about the best method for feeding an infant while using this medication.

Topamax can lead to serious eye disorders called acute myopia and secondary angle closure glaucoma. Both conditions can cause permanent blindness if left untreated.

Acute myopia is the medical term for very nearsightedness, a vision condition in which people can see nearby objects clearly, but objects at a distance appear blurred.

Secondary angle closure glaucoma happens when the angle between the iris and cornea begins closing. The condition develops very quickly and has been reported in children and adults.

Even low doses of topiramate can cause angle closure glaucoma, acute myopia and other eye problems. A 2010 case report in the Oman Journal of Opthalmology described a 23-year-old who developed the disorders while taking just 25 mg daily. Typical doses are usually in the range of 50 mg to 400 mg per day.

Symptoms of these eye disorders typically occur within one month of starting Topamax. People taking the drug should seek immediate medical attention if they experience blurred vision, visual disturbances or pain around the eyes.

The main treatment to reverse symptoms of myopia and secondary angle closure glaucoma is to stop taking the medicine as soon as possible. However, do not stop taking the drug without consulting your doctor. A doctor may also provide medications to lower fluid production or increase its outflow.

Fact
Secondary angle closure glaucoma usually goes away within 24 to 48 hours with medical treatment. It can take one to two weeks after stopping Topamax for the myopia to resolve.
Source: American Academy of Opthalmology

Partial vision loss unrelated to eye pressure has also been reported in clinical trials and in postmarketing experience in people taking topiramate. Most of these visual field defects went away after the patient stopped using the drug.

The drug’s label advises doctors and their patients to consider discontinuing the medication if visual problems occur at any time during treatment.

200 Studies Show Increased Risk of Suicidal Thoughts

Topamax can increase the risk of suicidal thoughts or behavior. People who take the drug should be monitored for signs of new or worsening depression, increased anxiety or panic, and/or any unusual changes in mood or behavior.

In 2008, the FDA completed a review of nearly 200 medical studies that showed antiepileptic drugs cause an increase in suicidal thoughts and behaviors. Based on the outcome of this review, the FDA required all manufacturers of drugs in this class to include a warning in their labeling and develop a medication guide for patients to inform them of the risks of suicidal thoughts and behaviors.

Clinical Trial
In a clinical trial, four people taking anticonvulsant drugs committed suicide. No patients taking the placebo took their own lives.
Source: U.S. Food and Drug Administration Prescribing label for Topamax

The FDA’s pooled analyses involved 199 placebo-controlled clinical trials of 11 different antiepileptic drugs (AEDs). It showed that patients taking AEDs had about twice the risk of suicidal thinking or behavior compared to patients taking a placebo.

Patients in these trials took the drugs for an average of 12 weeks. In that time, the estimated incidence rate of suicidal thoughts or behavior among 27,863 AED-treated patients was 0.43 percent, compared to 0.24 percent among 16,029 placebo-treated patients. The analysis found an increase of about one case of suicidal thinking or behavior for every 530 patients treated.

“The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed,” according to the Topamax prescribing information. “Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.”

Please seek the advice of a medical professional before making health care decisions.

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Nurse Amy Keller
Written By Amy Keller, RN Registered Nurse

Amy Keller is a registered nurse and award-winning journalist with 22 years of experience writing about politics, business, health and other topics. At Drugwatch, she draws on her clinical experience and investigative reporting skills to write about consumers’ health concerns such as the safety of online pharmacies. She also provides informed analysis on complex health issues. Some of her qualifications include:

  • Recipient of USF’s Nurse Alumni Nightingale award for excellence in nursing
  • Guest Faculty Speaker, “Moving Forward with Patient- and Family-Centered Care Intensive Training Seminar”
  • Member of Sigma Theta Tau International Honor Society of Nursing
Edited By

8 Cited Research Articles

  1. American Academy of Ophthalmology. (n.d.). Drug-Induced Secondary Angle-Closure Glaucoma. Retrieved from  https://www.aao.org/bcscsnippetdetail.aspx?id=9a566956-c299-41ee-8e33-919bff427d48
  2. American Optometric Association. (n.d.). Myopia (Nearsightedness). Retrieved from  https://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/myopia?sso=y
  3. Centers for Disease Control and Prevention. (2014, October 22). Key Findings: Use of topiramate in pregnancy and risk of oral clefts. Retrieved from  https://www.cdc.gov/ncbddd/birthdefects/features/birthdefects-topiramate-keyfindings.html
  4. Hunt, S., Russell, A., Smithson, W.H., Parsons, L., Robertson, L., Waddell, R., Irwin, B., Morrison, P.J., Morrow, J., and Craig, J. (2008, July 22). Topiramate in pregnancy. Preliminary experience from the UK Epilepsy and Pregnancy Register. Neurology. Retrieved from  https://n.neurology.org/content/71/4/272.abstract?sid=5f03c4c5-72df-4c0d-95bf-8dd1db43feac
  5. Natesh, S. et al. (2010, January-April). Topiramate-induced angle closure with acute myopia, macular striae. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886232/
  6. U.S. Food and Drug Administration. (2018, March 4). FDA Drug Safety Communication: Risk of oral clefts in children born to mothers taking Topamax (topiramate). Retrieved from https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-risk-oral-clefts-children-born-mothers-taking-topamax-topiramate
  7. U.S. Food and Drug Administration. (2017, May). Highlights of prescribing information. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/020505s057_020844s048lbl.pdf
  8. U.S. Food and Drug Administration. (2016, April 8). Questions and Answers: Risk of oral clefts (cleft lip and/or palate) in infants born to mothers taking Topamax (Topiramate). Retrieved from  https://wayback.archive-it.org/7993/20170723113146/https://www.fda.gov/Drugs/DrugSafety/ucm245470.htm
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