Topamax (Topiramate) for Weight Loss
Medically reviewed by Lindsay Cook, PharmD
Topamax (topiramate) is an anticonvulsant or a drug used to treat seizures. It is also approved to prevent migraine headaches.
While Topamax is not approved by the Food and Drug Administration (FDA) as a weight loss drug, it can be used off-label for this purpose. Multiple clinical trials have demonstrated that Topamax may help people lose weight when taken in addition to making lifestyle changes like regular exercise and a reduced-calorie diet.
This article explores the use of Topamax for weight loss, how it works, how to take it, potential side effects, and more.
Getty Images / Grace Cary
Uses of Topamax
The FDA approved Topamax for:
Treatment alone or in combination with other drugs for partial-onset or primary generalized tonic-clonic seizures in people 2 years and older
Prevention of migraines in people 12 years and older
The drug topiramate is also available in combination with the medication phentermine as one drug product called Qsymia, which is FDA-approved to treat obesity.
Qsymia is meant to be used in people with a body mass index (BMI) of 30 kilograms per square meter or greater, or a BMI of 27 or higher if the individual also has an obesity-related condition such as type 2 diabetes, high blood pressure, or high cholesterol.
Topamax alone is not FDA-approved to treat obesity. However, a healthcare provider may still prescribe it instead of Qsymia when they want the benefits that topiramate brings without the effects of phentermine, either because an individual can’t take phentermine or if they are experiencing side effects.
Furthermore, topiramate may be enough to help some people lose weight and avoid the use of extra medication they don’t need.
About BMI
BMI is a dated, biased measure that doesn’t account for several factors, such as body composition, ethnicity, race, gender, and age.
Despite being a flawed measure, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes.
Research on Topamax’s Use for Weight Loss
Multiple clinical trials have shown that Topamax can lead to significant weight loss when combined with a reduced-calorie diet and exercise regimen.
One study organized 385 people into groups by BMI and then were randomized to receive a placebo (nontherapeutic substance) or topiramate at different dose levels, including:
60 milligrams (mg) daily
96 mg daily
192 mg daily
384 mg daily
All participants also had similar lifestyle plans, including diet adjustments and regular exercise.
After 24 weeks, the placebo group lost an average of 2.6% of their body weight. The topiramate groups saw their weight drop from 4.8% to 6.3%, depending on their dosage.
Another study consisted of 854 people ages 18 to 75 years with a BMI of 27 to 50. All participants were assigned to weight loss programs involving diet and exercise adjustments as well as either placebo or varying doses of Topamax for a full year.
At 60 weeks, the placebo group lost 1.7% of their baseline body weight, while the Topamax groups lost 7 to 9.7%. The Topamax group also showed improved blood pressure and insulin requirements.
What Is “Off-Label” Use?
When a healthcare provider uses an FDA-approved drug for an unapproved use, that use is considered off-label. When the FDA approves a drug for any use, they deem it safe for its intended uses. This doesn’t mean that the drug has no side effects but that its benefits outweigh side effects risks based on clinical trials for certain diseases or conditions.
However, providers are generally able to use their medical expertise to prescribe FDA-approved drugs for unapproved uses as long as they judge that the drug is medically appropriate for you. They may do this because another drug is unavailable or you have tried other medications for a condition or disease, and they have not worked well enough.
How Does Topamax Work for Weight Loss?
Topamax treats seizures by acting on calcium and sodium channels and GABA receptors, which help to lower the seizure threshold.
These actions also help suppress your appetite, resulting in lower calorie intake, and make you feel more full by changing the way your body uses energy.
Topamax may also help with binge eating tendencies by changing the reward pathway associated with food, which can make cravings or the idea of overeating less appealing.
Dosage: How Much to Take for Weight Loss
The most common doses of Topamax used in clinical trials associated with significant weight loss were 96 mg or 192 mg per day, but some doses used were higher or lower.
It may also be necessary to start with a lower dose of Topamax and slowly increase (or titrate) to a higher level based on your tolerance and possible side effects.
Your healthcare provider will use their best judgment and work with you to determine the best starting dose and titration schedule for Topamax.
Is There a Best Time of Day to Take Topamax?
What time of day and how often you take Topamax will depend on whether you're taking the regular or extended-release (ER) formulation. Regular tablets and capsules may need to be taken up to twice a day, once in the morning and once at night. ER formulations only need to be taken once a day, ideally at the same time each day.
Your healthcare provider may suggest taking Topamax in the morning when you wake up to prevent trouble sleeping at night. However, the drug tends to make some people sleepy, in which case taking it at night before bed would be a better option.
You can take Topamax with or without food. Studies have shown that taking Topamax with food may extend the time needed for the drug to reach peak concentration in your blood, but it does not affect how much of the drug your body absorbs. So, you'll be able to take it without regard to meals and snacks.
Side Effects
Topamax can cause a range of side effects. One important note is that your prescriber should take a baseline serum bicarbonate blood level before starting you on Topamax, as the drug can affect acid-base levels. This measurement is available as part of an electrolyte or metabolic lab panel.
If you have any kidney disease or are at risk for kidney disease, your healthcare provider should also take a baseline glomerular filtration rate (GFR), This is a measure of kidney function against which they can compare future readings to monitor whether Topamax affects your kidneys.
Other potential side effects include:
Paresthesia, or “pins-and-needles” sensations
Fatigue
Dizziness
Sleepiness
Mood changes
Suicidal ideation
Taste disturbance or loss of appetite
Impaired memory or concentration, such as difficulty finding certain words or slowed mental processing
Precautions: Who Should Not Take Topamax?
Topiramate is not appropriate for every population. You may need to avoid taking it if you have:
Persistent electrolyte disorders such as metabolic acidosis
Glaucoma, specifically a certain type called angle closure glaucoma, has been rarely associated with taking Topamax
Alcoholism or if you drink frequently, as alcohol can significantly increase your risk of side effects from topiramate, plus extended-release topiramate (Trokendi XR) cannot be used within six hours before or after taking due to altered levels of the medication in your body
Hyperthyroidism
Other Options for Obesity Treatment
Lifestyle interventions without using medication should typically be the first weight loss choice for people with obesity. Many of these intervention programs exist within a variety of treatment settings, with a variety of providers and protocols, but in general, they aim to:
Add physical activity to your life in convenient ways that you enjoy and that are shown to be effective for weight loss
Provide education on how to deal with stress in healthy ways
Cope with challenges that can derail your hard work—like how to choose healthy food when eating out
Learn about healthy eating and how you can incorporate it into your lifestyle
Although responses and success rates will vary greatly from person to person, these programs are generally shown to be successful.
Pharmacotherapy, or using medication to treat obesity, is indicated for people who have a BMI of 30 or greater or 27 or greater with weight-related comorbidity if they have not had enough success with weight loss after trying lifestyle interventions alone.
However, take note that antiobesity medications are indicated as add-ons to healthy lifestyle habits, not replacements. Current FDA-approved obesity drugs include:
Xenical or Alli (orlistat)
Belviq (lorcaserin)
Saxenda (liraglutide)
Wegovy (semaglutide)
Qsymia (phentermine/topiramate)
Contrave (naltrexone/bupropion)
Zepbound (tirzepatide)
Weight loss achieved with these drugs ranges from 3% to 9% of initial body weight.
For individuals with a BMI of 40 or greater, or 35 or greater with weight-related comorbidity, who have tried both lifestyle interventions and medication therapies without sufficient weight loss success, bariatric surgery is another treatment choice. The two most common types are Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy.
Both can lead to fast and stable weight loss for many people. Some people, however, fail to achieve their weight loss goal even with a successful surgery. For others, weight loss tends to plateau after about one year, or people begin to regain weight after one to two years due in part to nutritional and exercise habits following surgery.
The best chance at a successful bariatric surgery is to go into it with realistic expectations, readiness for behavior changes, knowledge about nutritional and exercise requirements to keep weight off, and to plan on utilizing a team of healthcare providers after surgery for continued support.
Summary
Topamax is one option in a long list of medications and other treatment options for the obesity epidemic. It works to suppress your appetite, resulting in lower calorie intake. It can also make you feel more full by changing how your body uses energy.
Side effects can be a limiting factor in taking Topamax. They may include paresthesias, impaired memory or concentration, mood changes, and sleepiness.
Weight loss as a percentage of baseline body weight ranged from a 4.8% to a 9.7% decrease in multiple clinical trials that included Topamax. Therefore, it may be a good option for many people trying to lose weight as a drug treatment option along with dietary and exercise lifestyle interventions.
Read the original article on Verywell Health.
