Uses and Side Effects of Topamax

Helpful for Sleep Eating, Seizures, and Weight Loss

Topamax is a prescription medication sold under the generic name topiramate. It is most commonly prescribed to treat seizures and for prevention of migraine headaches. It also seems to help with weight loss. Learn more about how Topamax works and the most common side effects.

Woman asleep in bed
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The primary use of Topamax is for seizure disorders that occur as part of epilepsy, as well as for mood stability, chronic nerve pain and migraine prevention. Even though it decreases appetite, Topamax should not be prescribed solely for this purpose since it is a powerful medication that can—albeit infrequently—have serious side effects.

How It Works

The exact mechanism of action explaining how Topamax works is not known. It blocks sodium channels in the body which open and close in response to specific levels of charged chemicals. It also enhances the activity of a chemical messenger, or neurotransmitter called GABA. In addition, it interferes with receptors on cells for a chemical called glutamate. It also inhibits an enzyme called carbonic anhydrase.

Who Should Not Use Topamax

Topamax should not be used if you are pregnant. Caution is advised if you are breastfeeding. It may not be the best medication to use if you have liver, kidney, or lung problems. It should not be used with alcohol or other medications that depress the central nervous system (especially those that may affect the brain). People born with certain congenital disorders of metabolism should not use Topamax.

If you have a history of depression, especially with thoughts of suicide, or a history of kidney stones (called nephrolithiasis), it should be used with caution. Caution is also advised if you have low potassium levels in the blood (hypokalemia) or metabolic acidosis, especially as part of diarrhea or dehydration from a hot environment.

The medication may not be appropriate in those with epilepsy who are treated with a ketogenic diet. Further caution is advised in the setting of surgery.

Common Side Effects

As may happen with the use of any prescription drug, there is a potential risk for side effects when using Topamax. Although most people do not experience most or any of these side effects, some that may occur include:

  • Slowed thinking (leading to the nickname "Dope-a-max")
  • Fatigue or sleepiness
  • Insomnia
  • Mood changes (depression, nervousness, or anxiety)
  • Dizziness or unsteadiness (ataxia)
  • Vision changes (including nystagmus and double vision)
  • Weight loss, taste changes, or loss of appetite (anorexia)
  • Hair loss (alopecia)
  • Nausea, upset stomach, stomach pain, or diarrhea
  • Decreased or altered sensation or tingling (paresthesia)
  • Tremor
  • Weakness
  • Fever
  • Infection such as urinary tract infection (UTI) or sinusitis
  • Metabolic acidosis

Potential Serious Reactions

There are also potentially serious side effects that may occur with the use of Topamax. These serious reactions occur more rarely. With the use of Topamax, some of the potential serious side effects include:

  • Severe metabolic acidosis
  • Kidney stones (nephrolithiasis)
  • Bone density changes (osteomalacia or osteoporosis)
  • Decreased sweating (oligohidrosis)
  • Elevated body temperature (hyperthermia)
  • Low potassium levels (hypokalemia)
  • Hyperammonemic encephalopathy (manifest as confusion)
  • Psychosis or suicidality
  • Blood cell count changes (leukopenia or anemia)
  • Vision problems including glaucoma, acute myopia, or maculopathy
  • Severe skin reactions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, and erythema multiforme
  • Growth suppression (in children)
  • Neonatal cleft lip or palate (if used by pregnant women in the first trimester)
  • Withdrawal seizures with abrupt discontinuation

Safety Precautions and Monitoring

As described in detail above, there are certain people who should not use Topamax or who should use it only with caution. Topamax requires some blood tests, with creatinine and bicarbonate checked at baseline and then periodically.

The medication may interact with other drugs, and all your medications should be carefully reviewed by your healthcare provider and pharmacist to avoid potential problems. In addition, it is important to identify depression, behavior changes, and any thoughts of suicide as these may require discontinuation of the medication.

Due to a risk of seizure, the medication should not be stopped abruptly without consultation with your healthcare provider.

If you experience any difficulties with the use of Topamax, you should be in close contact with your primary healthcare provider.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Abtahi MA, Abtahi SH, Fazel F, et al. Topiramate and the vision: a systematic review. Clin Ophthalmol. 2012;6:117-31. doi:10.2147/OPTH.S27695

  2. Abtahi MA, Abtahi SH, Fazel F, et al. Topiramate and the vision: a systematic review. Clin Ophthalmol. 2012;6:117-31. doi:10.2147/OPTH.S27695

  3. United States Food and Drug Administration; Ortho-McNeil Pharmaceutical Inc. Topamax: FDA approved labeling text.

  4. Paul E, Conant KD, Dunne IE, et al. Urolithiasis on the ketogenic diet with concurrent topiramate or zonisamide therapy. Epilepsy Res. 2010;90(1-2):151-6. doi:10.1016/j.eplepsyres.2010.04.005

  5. Margulis AV, Mitchell AA, Gilboa SM, et al. Use of topiramate in pregnancy and risk of oral clefts. Am J Obstet Gynecol. 2012;207(5):405.e1-7. doi:10.1016/j.ajog.2012.07.008

By Brandon Peters, MD
Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist.