by Dimitri Gitelmaker, MD

As a physician board certified in obesity management, I understand the importance of evidence-based information when it comes to prescribing medications for weight loss. In this blog post, I will provide a comprehensive comparison of five popular weight loss medications – topiramate, bupropion, naltrexone, phentermine, and GLP-1 agonists – supported by clinical studies that demonstrate their effectiveness.

Topiramate

Topiramate’s (brand name Topamax) weight loss potential was first observed in patients treated for epilepsy. A study by Kramer et al. (2010) found that topiramate led to a mean weight loss of 7.3% over 56 weeks in patients with obesity (BMI ≥ 35 kg/m²) [1]. However, side effects such as paresthesia, taste disturbance, and memory impairment may limit its use in some patients. Reference: [1] Kramer, C. K., Leitão, C. B., Pinto, L. C., Canani, L. H., Azevedo, M. J., & Gross, J. L. (2010). Efficacy and safety of topiramate on weight loss: a meta-analysis of randomized controlled trials. Obesity Reviews, 12(5), e338-e347.

Bupropion

Bupropion (brand name Welbutrin) has been shown to promote weight loss through its effects on dopamine and norepinephrine levels. A study by Anderson et al. (2002) found that patients receiving bupropion experienced a mean weight loss of 7.2% over 24 weeks [2]. Common side effects include insomnia, dry mouth, and increased heart rate. Reference: [2] Anderson, J. W., Greenway, F. L., Fujioka, K., Gadde, K. M., McKenney, J., & O’Neil, P. M. (2002). Bupropion SR enhances weight loss: a 48-week double-blind, placebo-controlled trial. Obesity Research, 10(7), 633-641.

Naltrexone/Bupropion (Contrave)

The combination of naltrexone and bupropion has shown increased effectiveness compared to either drug alone. A study by Greenway et al. (2010) found that patients treated with naltrexone/bupropion experienced a mean weight loss of 5.0-9.3% over 56 weeks [3]. Common side effects include nausea, constipation, and headache. Reference: [3] Greenway, F. L., Fujioka, K., Plodkowski, R. A., Mudaliar, S., Guttadauria, M., Erickson, J., … & Dunayevich, E. (2010). Effect of naltrexone plus bupropion on weight loss in overweight and obese adults (COR-I): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet, 376(9741), 595-605.

Phentermine

Phentermine’s, commonly known as Adipex, short-term effectiveness for weight loss is well-established. A meta-analysis reported a mean weight loss of 3.6 kg (95% CI: 3.0–4.2 kg) more than placebo after 3 months of treatment. However, its use is limited to 12 weeks due to the potential for addiction and side effects such as increased heart, malnutrition, and more.

GLP-1 Agonists

GLP-1 agonists have demonstrated significant weight loss potential in clinical trials. A notable example is liraglutide (Saxenda), which was found to induce a mean weight loss of 5.6-8.0% over 56 weeks in a study by Pi-Sunyer et al. Semaglutide has shown even more promising results, with a mean weight loss of 14.9% over 68 weeks. Common side effects of GLP-1 agonists include gastrointestinal issues such as nausea, vomiting, and diarrhea.

As a medically trained physician, my goal is to provide evidence-based information to help patients make informed decisions about their weight loss journey. Topiramate, bupropion, naltrexone, phentermine, and GLP-1 agonists have varying degrees of effectiveness and side-effect profiles. It’s essential to discuss your options with your healthcare provider and consider your medical history, potential side effects, and individual preferences when choosing the most suitable medication for your weight loss goals.

Dr. Dimitri Gitelmaker, M.D. is board certified in internal medicine, obesity management and preventive medicine and practices internal medicine in Hollywood, FL. Dr. Dimitri provides functional medicine in a direct primary care setting to those who wish to receive a modern day approach to traditional medicine standards. His philosophies are based on preventive and proactive measures with special focus on proper nutrition and dieting, fitness and lifestyle modifications to improve, reverse and prevent common chronic medical conditions.