Topamax for Weight Loss: Pros & Cons

If you've heard about Topamax for weight loss, you might be wondering how a seizure and migraine medication fits into the picture. While it’s not FDA-approved for weight management, Topamax (topiramate) has gained attention for its appetite-suppressing side effects that can lead to noticeable weight loss. 

This guide will explore how it works, what kind of results to expect, potential side effects, and how it compares to other weight loss options.

What is Topamax?

Topamax is a prescription anticonvulsant medication used to manage seizures and prevent migraines. Weight management is an off-label use. The brand-name product Topamax contains topiramate as the active ingredient.

How Does Topamax Promote Weight Loss?

Topamax reduces appetite and increases feelings of fullness, which can lead to reduced calorie intake and weight loss. 

Clinical studies show that 6 to 17% of users experience weight loss, especially when combined with a low-calorie diet and exercise.

While Topamax alone is not FDA-approved for weight loss, it is a key component of the FDA-approved combination drug, Qsymia, which includes topiramate and phentermine, a prescription appetite suppressant. 

How Effective is Topamax for Weight Loss?

Research shows that people taking 96 to 200 mg/day of topiramate lose an average of 5 to 10% of their body weight. If you weigh 230 pounds initially, you can expect to lose 10 to 20 pounds on this medicine.

Results vary with dosage and treatment duration, with higher doses and longer use leading to more weight loss.

Who is Eligible For Qsymia?

Qsymia is suitable for individuals with a body mass index (BMI) of 30 kg/m2 (obese) and those with a BMI of 27 kg/m2 (overweight) who have at least one weight-related health problem, such as high blood pressure, high blood sugar levels, or high cholesterol. 

The FDA has approved Qsymia (phentermine and topiramate) in children aged 12 years and older whose BMI is at the 95th percentile or higher, standardized for age and gender.

Typical Dosage and Guidelines

Dosing

• Qsymia: 

  • Dosage starts at 3.75 mg/23 mg and is increased over time if needed

  • Extended-release capsules taken by mouth once a day in the morning

  • Take the medicine with or without food

• Topamax:

  • Dosage for seizure management is 64 mg to 400 mg per day

  • Dosage for weight loss starts at 25 mg to 50 mg once daily, not to exceed 200 mg daily

  • While higher doses may result in more weight loss, they are also associated with more side effects.

Avoid taking the capsule in the evening because phentermine is a stimulant and can cause sleep difficulties. 

Phentermine and topiramate can be habit-forming. Do not change the dose, dosing frequency, or treatment duration without talking to your health care professional.

Missed Dose

If you miss a dose of your medicine, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and return to your regular dosing schedule. Do not take extra medicine to make up for a forgotten dose.

Stopping Treatment

Phentermine and topiramate help with weight loss only as long as you continue on the medicines. 

Do not stop taking Topamax abruptly, as this can increase the risk of seizures. Always consult your healthcare professional before making any changes to your medication. They can guide you on how to decrease the dose if needed safely. 

How Long Does It Take For Topamax To Work For Weight Loss?

It may take about 4 weeks for Topamax to work for weight loss. They will measure weight loss after 12 weeks of treatment. They may consider an additional dose increase if you are not losing weight adequately. 

Remember, Topamax helps you lose weight by giving you a sensation of fullness sooner and suppressing your appetite. Therefore, it does not cause immediate weight loss. 

Does Topamax Target Belly Fat?

Studies have shown that topiramate can reduce the waist-to-hip ratio, potentially helping with belly fat after 4 to 6 weeks of treatment.

Side Effects and Risks of Topamax

Common Side Effects 

• Decreased appetite and weight loss

• Dizziness

• Unusual sensations (numbness, tingling, burning) 

• Decreased sensations in the skin

• Memory or speech issues

• Dry mouth

• Changes in taste

• Stomach pain, nausea, diarrhea

• Dysmenorrhea (pain with menstrual periods)

• Cold and flu-like symptoms

Serious Risks and Warnings

Seek immediate medical attention if you experience any of the following:

• Suicidal behavior or thinking

• Increased heart rate (palpitations or racing heart)

• Vision issues

• Mood changes and cognitive changes

• Cognitive impairment (difficulties with concentration, attention, memory, speech).

• Metabolic acidosis (too much acid and low serum bicarbonate levels)

• Kidney stones, osteomalacia, and osteoporosis

• Birth defects during pregnancy

• Decreased kidney function

• Allergic reactions (skin reactions and breathing problems)

Note that phentermine and topiramate can cause unexpected changes in your mental health, including suicidal thinking and behaviors, within a week of starting treatment. 

Call your doctor immediately if you notice any unusual mood changes. 

Who Should Not Take Topamax or Qsymia?

Certain health conditions: Topamax/Qsymia may not be safe for people with certain medical conditions, including glaucoma, hyperthyroidism, kidney disease, liver disease, or mental health disorders.

Pregnant Women: Before starting treatment with Topamax or Qsymia, tell your doctor if you are pregnant or planning a pregnancy in the near future, as phentermine and topiramate can cause serious congenital disabilities in the unborn baby, including cleft lip and cleft palate. 

You must take birth control pills (oral contraceptives) or use some other method of contraception to prevent pregnancy during weight loss treatment with phentermine and topiramate. 

If you become pregnant while on phentermine and topiramate, stop the medicine and call your doctor without delay.

What Should You Avoid While Taking Topamax or Qsymia?

Alcohol

You should avoid alcohol consumption while taking this medication as it can worsen drowsiness and dizziness. 

Heavy Machinery

Phentermine and topiramate can affect your vision, cause dizziness, and slow your thinking and reaction time. Do not drive a car or operate machinery until you know how this weight loss drug affects you. 

Heat Exposure

Avoid unnecessary heat exposure, stay hydrated, and call your doctor if you have ongoing diarrhea, upset stomach, headache, fever, or muscle cramps. Qsymia can prevent your body temperature from cooling down through sweating. 

Alternatives to Topamax for Weight Loss

Other FDA-approved prescription weight loss drugs include:

• Orlistat 120 mg (Xenical)

• Phentermine/topiramate ER (Qsymia)

• Phentermine (Adipex, Lomaira)

• Naltrexone/bupropion (Contrave)

• Liraglutide (Saxenda)

• Semaglutide (Wegovy)

• Tirzeptide (Zepbound)

Is Topamax Better Than Metformin for Weight Loss?

Studies show that Topamax tends to cause slightly more weight loss than metformin, a prescription medicine used to treat type 2 diabetes. Though both have benefits, Topamax may be more effective at reducing waist size.

Healthy Lifestyle Tips to Support Topamax Weight Loss

• Eat a balanced, healthy, reduced-calorie diet.

• Exercise regularly.

• Stay well hydrated.

• Control portion sizes.

• Lose weight gradually at a steady pace of about 1 to 2 pounds a week.

• Manage stress.

• Join support groups such as social networks, exercise clubs, or counseling groups.

• Reduce screen time and sedentary behaviors and increase physical activity.

Topamax Drug Interactions

Certain medicines, including Monoamine oxidase inhibitors (MAOIs) such as isocarboxazid (Marplan), selegiline (Eldepryl, Emsam, Zelapar), phenelzine (Nardil), and tranylcypromine (Parnate), can interact with topiramate and phentermine.