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Topamax for Weight Loss: Uses, Dosage, Side Effects, and Efficacy

<p>Topamax for Weight Loss: Uses, Dosage, Side Effects, and Efficacy</p>
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 6 min read

According to the Centers for Disease Control and Prevention (CDC), a staggering 41.9% of adults in the United States were clinically obese in 2020. With millions of people struggling to lose weight, health experts and average Americans alike are looking for fast and effective methods to lose weight. While diet and exercise are crucial to achieving this feat, there are medications on the market that can help to maximize these efforts. One of the most recognizable medications used for weight loss is Topamax. Many people who struggle with being overweight or obese have reported they lose far more weight when taking Topamax than with diet or exercise alone. 

Uses of Topamax

Topamax is the brand name for an anticonvulsant medication known as topiramate. Topiramate is most commonly prescribed by doctors to treat patients with conditions like epilepsy and migraines. Although the intricate mechanisms of how Topamax works within the brain are not fully understood, health care professionals know that the medication prevents certain cells from becoming overly stimulated. In turn, the cells are stabilized and a specific neurotransmitter (a cell that transfers chemical messages to others) in the brain increases its level of activity instead. While there is still a lot left to discover about how topiramate works, it is highly effective in reducing the occurrence of both seizures and migraine headaches for sufferers.

Even though Topamax was initially developed to treat epelectic seizures, it is frequently used to treat other medical conditions. Some of the most common off-label uses for Topamax include the treatment of bipolar disorder, borderline personality disorder, obsessive-compulsive disorder and certain substance abuse disorders. In recent years, Topamax has also been prescribed to those who are struggling to lose weight. This is because the medication is able to effectively decrease a person's appetite and potentially speed up their metabolism, which then leads to weight loss over time. Despite its rising popularity as a weight loss aid, Topamax is not approved by the U.S. Food and Drug Administration (FDA) for this use. It is worth noting; however, that the weight loss drug, Qsymia, is FDA-approved for weight loss and contains topiramate. 

In many scenarios, when a doctor prescribes the use of a topiramate for weight loss, it is used in conjunction with another medication known as phentermine. This active ingredient is also found in the FDA-approved weight loss drug, Qsymia. When used for the sole purpose of weight loss, these active ingredients do not work alone to produce results. They must be paired with a reduced calorie diet and regular exercise to achieve weight loss goals. When taken as prescribed and paired with healthier lifestyle choices, patients can quickly and effectively shed excess pounds. In turn, they are able to prevent or manage conditions like diabetes, high blood pressure or heart disease. 


When a doctor prescribes Topamax to a patient, the dose that is given is largely dependent upon the condition that is being treated. Those who are being treated for epilepsy may require a dose of up to 400mg per day, whereas a patient with migraines may only need 25-60mg. Prescribing doctors will use basic dosing guidelines when first prescribing these medications, starting with the lowest possible dosage. Over time, they will evaluate the patient's symptoms and reactions to the medications. This will allow them to fine tune the dosage until it eliminates the symptoms experienced by each individual. If the maximum recommended daily dosage is exceeded and symptoms persist, doctors may add in additional medications to work in unison with Topamax.

In the absence of other conditions used to treat Topamax, it can be prescribed as a weight loss aid. For this purpose, Topamax is paired with an additional medication known as phentermine. Adults and children who are over the age of 12, typically begin with a dose of 3.75mg of phentermine and 23 mg of topiramate. The prescribing doctor will monitor the effectiveness of the combination and adjust the dosage as necessary. Typically, for weight loss purposes, the daily dosage of phentermine is a maximum of 15 mg while the recommended daily limit of topiramate is 92 mg. Patients are advised to take these medications once per day.

Side Effects

Regardless of the health condition that is being treated with Topamax, there is a risk of side effects. For some patients, side effects may be severe and disruptive while others may experience little to no discomfort on the medication. It is important to understand that when a doctor prescribes Topamax to a patient, they believe that benefits of the medication heavily outweigh the risks associated with it. Patients should never discontinue their medication without first speaking to the doctor; however, if severe side effects are noted, seek medical care immediately. For mild side effects, it is still important to mention them to the prescribing doctor at an upcoming checkup. This will help the doctor to determine whether the dosage needs to be adjusted for maximum efficiency. 

Some of the most common side effects of Topamax, include:

  • Drowsiness

  • Nausea

  • Diarrhea

  • Loss of appetite

  • Changes in mood

  • Dizziness

  • Fatigue

  • Nervousness

  • Changes in taste

  • Mild fever

  • Sore throat, stuffy/runny nose

These common side effects are normal and can typically wait to be addressed at an upcoming appointment. However, there is a risk of more serious side effects. If any of the following side effects are experienced while taking Topamax, seek immediate medical attention:

  • Speech/language difficulties

  • Slowed mental or physical activity

  • Changes in vision

  • Confusion

  • Impaired memory

  • Burning or tingling sensations in the arms or feet

  • Uncontrolled eye movement

  • Extreme weakness or tiredness

  • Difficulty breathing/shortness of breath

  • High fever

  • Pain in the lower back or side

  • Difficulty urinating

  • Irregular heartbeat


As with all medications, results tend to vary from one person to the next. When it comes to treating certain conditions like epilepsy, Topamax is one of the most effective treatments for reducing the occurrence of partial-onset seizures. When it comes down to the efficacy of Topamax for weight loss, there are promising results. In a study conducted by the International Association for the Study of Obesity, participants that took a daily dose of topiramate for at least sixteen weeks lost 12 pounds more than those who were given placebos. Another study shows that these effects are achieved among  6-17% of patients who take Topamax for the treatment of any condition.

The Bottom Line

While Topamax has been proven to produce weight loss results in some patients, there is still much to be discovered about the specific mechanisms of the drug and how it interacts with one's appetite and metabolism. For those who are clinically obese or overweight with additional medical complications, Topamax can produce the desired results to get these health concerns under control quickly. Unfortunately, for those suffering from eplieptic seizures or migraines, the medication can produce results similar to those of a diet pill. In these scenarios, weight loss may be detrimental to the health of patients with underweight or healthy Body Mass Index (BMI) calculations. Patients who are taking Topamax, whether weight loss is intended or not, should track their weight loss and address any concerns they may have with their prescribing doctor. 


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This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.