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If you’re trying to lose weight, chances are you’ve traveled down the interweb’s rabbit holes researching any and allover-the-counter supplements and prescription medications for weight loss. It’s easy to get lost in Google—you’ve likely read about and tried every diet out there. You may have come across the prescription drug topiramate (or recognize its brand name, Topamax®).
Topiramate is an anticonvulsant medication used to treat certain seizures, epilepsy, and migraines. Ongoing research is also being done on its efficacy in treating alcoholism, post-traumatic stress disorder (PTSD), and binge-eating disorder. In research, topiramate has been shown to increase serotonin levels in children 2 to 12 years of age. And according to the National Alliance on Mental Health (NAMI), topiramate works in the brain to treat bipolar disorder, also known as manic depression.
The drug was first synthesized in 1979 and received approval from the U.S. Food and Drug Administration (FDA) in 1996 as an antiepileptic drug.
As more and more patients started taking topiramate, the medical community began noticing weight loss as a side effect of topiramate. They were intrigued by the idea topiramate might help treat conditions like overweight and obesity and asked: Could topiramate help reverse this growing epidemic?
In 2012, after years of clinical trials, the FDA approved Qsymia®—a controlled-release combo of phentermine and topiramate—for chronic weight management in adults with a body mass index (BMI) of 30 or greater or a BMI of 27 or above with at least one weight-related issue like high blood pressure or type 2 diabetes. Phentermine (another medication you may be familiar with) helps activate the sympathetic nervous system and may suppress appetite. Combined with topiramate, the duo may also increase satiety and help the body burn more calories .
So: Does topiramate cause weight loss, and what are the possible side effects? Let’s get to it and find out what topiramate weight loss is all about.
Obesity has almost tripled since 1975, according to the World Health Organization, and excess weight has been linked to an estimated 3 million deaths annually worldwide. It’s one of the leading contributors to preventable deaths in the United States. These numbers explain why drugs like topiramate are being prescribed off-label to support weight loss—in addition to diet and exercise.
Topiramate by itself can be prescribed off-label as a weight-loss drug. A paper on the first clinical trial for the use of the drug for obesity, published in 2003, found that topiramate produced significant weight loss in participants. Among 385 healthy obese participants, those on the two higher doses of topiramate lost an average of 6.3 percent of their body weight over 24 weeks, compared to the placebo group who dropped an average of only 2.6 percent.
Perhaps even more intriguing: The people in the study taking topiramate didn’t plateau during the study, which suggests that the weight-management benefits would continue. (However, it may mean taking the medication for an extended period of time to get the maximum results).
Even more, in 2013, the results of a 32-week clinical trial of 69 patients who had a BMI of between 27 and 50 in the Journal of Research in Medical Sciences: The Official Journal of Isfahan University of Medical Sciences revealed that topiramate helped with glycemic control in patients with type 2 diabetes. This finding suggests that topiramate helped to control blood sugar levels. What’s more, almost 50 percent of subjects had a body weight loss of at least five percent.
With any medication you take, there are risks of side effects. Truth be told, weight loss is a side effect of the topiramate in and of itself. So when taking this medication, if you suffer from overweight or obesity, losing weight is one of the most common side effects you’ll experience while on it.
But, although rare, there are other serious side effects we want you to be aware of when taking topiramate for weight loss. Contact your health care provider immediately if you experience any serious topiramate side effects. Here’s what to watch-out for:
Common topiramate side effects
temporary blurred vision
paresthesia (burning, prickling, or tingling sensations)
speech or language problems
drowsiness
memory problems
loss of appetite
generalized slowing of mental and physical activity
nervousness
dry mouth
fatigue
Serious topiramate side effects
suicidal thoughts
dizziness
eye redness or pain
increased eye pressure
menstrual changes or pain
kidney stones
trouble concentrating or paying attention
unusual tiredness or weakness
Current studies on topiramate (Topamax) show that it decreases appetite and may potentially stimulate your metabolism. A 2011 meta-analysis published in Obesity Review analyzing ten randomized controlled studies with 3320 participants found that those treated with topiramate lost an average of about 12 pounds more than the placebo group. Additionally, topiramate works to lower cravings and reduce appetite, aiding in weight loss.
In addition, studies performed on mice show that when they are given topiramate, their metabolic rate increases—meaning the number of calories burned at rest.But we prefer to focus on studies with human results because, after all, that’s what we are. That said, these rodent studies may also be promising for us in terms of weight loss if it has the same effect. We need more studies on how topiramate affects our metabolism, but we know that it causes weight loss in other ways.
Rekha Kumar, MD, Chief Medical Officer at Found, says, “Topiramate is used for many medical conditions such as migraines, seizures, and nerve pain but also is a helpful off-label option for weight loss which works by reducing hunger and cravings. Topiramate can be prescribed alone, in combination with other medication, or sometimes to counteract the weight gain potential of certain medicines.”
As mentioned above, weight loss is a side effect of topiramate. But, how exactly does it work to cause weight loss?
Great question. Scientists aren’t totally clear on what causes topiramate weight loss, but they hypothesize that, “topiramate most likely causes weight loss by appetite suppression through modulation of gamma-aminobutyric acid (GABA) receptors, causing glutamate inhibition, as well as increased dopamine release,” according to a 2019 review of weight-loss medications in Frontiers in Endocrinology.
Glutamate is the most abundant excitatory neurotransmitter in the brain. That means glutamate increases the possibility that a neuron will fire its “message” and carry it to the nextcell. Those with obesity may have higher than normal levels of glutamate and it needs to be regulated to induce weight loss. Even more, obesity is also linked to fewer dopamine receptors and topiramate works to facilitate the dopamine response in your body. Essentially, topiramate works both to manage glutamate levels and helps dopamine uptake in obese patients which may help with chronic weight management.
We totally get it; after reading the side effects, you may think ehhhh is this drug right for me? The best person to consult may be your Found health care provider. They’ll be able to cover the side effects of using topiramate for weight loss in-depth. They’ll also be able to talk about what other medications and supplements you shouldn't take when on topiramate. In addition, here are some lifestyle guidelines to keep in mind:
Don’t get dehydrated. The FDA cautions that in some cases during clinical trials, patients didn’t sweat normally, and their base temperature increased. Drink plenty of water. Also, if you feel warmer than usual, tell your doctor right away.
Steer clear of ketogenic (keto) diets. A keto plan is essentially high in fat and low in carbohydrates. Taking topiramate can cause metabolic acidosis—in other words, too much acid in the body—while a keto diet can cause ketoacidosis, leading to even more acid. And too much acid can cause kidney stones, kidney disease, or even kidney failure. Taking topiramate while following a keto diet could compound the problem and increase the risk of higher acid levels in the blood.
Avoid alcohol and illegal drugs. Alcohol and illegal drugs can decrease your benefits or worsen your symptoms if you take topiramate to treat a mental health disorder. And for patients taking topiramate either for its indicated use or off-label, alcohol and illegal drugs can increase negative side effects like dizziness and sedation, NAMI warns.
Reduce salt intake. The National Institute of Diabetes and Digestive and Kidney Diseases warns that sodium can increase the risk of developing kidney stones. (Check out the keto info above.) So it’s best to watch how much salt you’re getting in your diet to avoid upping your risk of kidney stones. The Dietary Guidelines for Americans recommends less than 2,300 mg of salt daily— about one teaspoon a day.
Watch out for certain birth control pills. A study published in 2023 in the international reproductive health journal, Contraception, looked at the efficacy of oral contraceptives among women taking topiramate. Researchers found that while the birth control pill was still just as effective when topiramate was taken at a low dose (equal to or lower than 200 mg), there were still 1.3 unintended pregnancies in every 100 women who were on hormonal birth control and topiramate. So, keep in mind this study suggests that topiramate may reduce the effectiveness of estrogen-containing contraceptives.
Armed with this information, you may want to consider progestin-only birth control or a non-hormonal method—like condoms. Similarly, if you’re pregnant or planning on becoming pregnant, in 2011, the FDA issued a warning that data showed an increased risk of cleft lip and/or palate in infants of women treated with topiramate.
Again, be sure to tell your health care provider your entire medical history and any medication or supplements you’re on for guidance on what not to take with topiramate.
Initially topiramate is taken in low doses—typically 25 mg to begin with to see how well your body tolerates it. Then, it can be bumped up to 50 mg daily. The doses are taken evenly, twice daily, and are typically increased weekly.
A study in the International Journal of Obesity found that 60 weeks of treatment led to an average of more than 9 percent loss in body weight while taking 192 mg of topiramate daily. Researchers concluded that lower doses of topiramate for weight loss may have a beneficial result over a longer period. As a note, when considering how to take topiramate for weight loss, this study looked at topiramate taken alone, finding people can lose weight on lower doses and in combination with behavior change. But, of course, the effective dose varies in individuals.
The medication is also offered in an extended-release form called topiramate XR. It comes in the same daily dose as but only needs to be taken once a day. So, like all of us, if life gets busy, it may be easier for you to remember to take that one dose daily instead of two times a day for topiramate weight loss.
Topiramate can take anywhere from a few days to several weeks to work. But, keep in touch with your health care provider over those first few weeks and let them know how you’re feeling. So the answer for how long it takes for topiramate to work can vary. Reviewing the research on topiramate, body weight reduction happens with time, and patients can continue to take it to manage their chronic obesity.
Remember, weight loss happens gradually—it’s a marathon, not a sprint—so if you’re not experiencing the results you’d like in the first couple of days, give it time. Topiramate isn’t a miracle diet pill; keep in mind you can always switch to a different med after topiramate to find what works best for you.
It’s clear topiramate weight loss is real and is worth considering when choosing what weight-loss medication is right for you. It’s been proven effective for long-term use and continues to be prescribed off-label for chronic obesity.
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GLP-1*
GLP-1 prescriptions, filled through your local pharmacy, are now available as part of Found's weight-loss toolkit. While GLP-1s are effective for weight loss, they are not clinically appropriate for everyone. Eligibility for a GLP-1 is based on a thorough evaluation of your medical history, eating behavior, lab work, and insurance coverage. If a GLP-1 is not appropriate for you, our providers will work with you to determine an effective medication for your health profile.
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SOURCES
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Bray, G.A., Hollander, P., Klein, S., Kushner, R., Levy, B., Fitchet, M. and Perry, B.H. (2003), A 6-Month Randomized, Placebo-Controlled, Dose-Ranging Trial of Topiramate for Weight Loss in Obesity. Obesity Research, 11: 722-733. https://onlinelibrary.wiley.com/doi/10.1038/oby.2003.102
The U.S. Food and Drug Administration. 4 Mar. 2011. FDA Drug Safety Communication: Risk of oral clefts in children born to mothers taking Topamax (topiramate). https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-risk-oral-clefts-children-born-mothers-taking-topamax-topiramate
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National Library of Medicine. 2022. TOPAMAX - topiramate. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=21628112-0c47-11df-95b3-498d55d89593
National Institute of Diabetes and Digestive and Kidney Disease. 2017. U.S. Department of Health and Human Services. https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-stones/eating-diet-nutrition
Rosenfeld WE, Doose DR, Walker SA, Nayak RK. Effect of topiramate on the pharmacokinetics of an oral contraceptive containing norethindrone and ethinyl estradiol in patients with epilepsy. Epilepsia. 1997 Mar;38(3):317-23. https://pubmed.ncbi.nlm.nih.gov/9070594/
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