Weight loss medications are an important component of a complete treatment plan for adults with obesity (BMI > 30) or overweight (BMI > 27) with increased adiposity complications. The benefits of weight loss medications include: appetite control, improvement of eating behavior, and slow progression of weight gain and regain.
Before 2012, there were few weight loss medications approved by the U.S. Food and Drug Administration (FDA). The top medications at that time were phentermine and orlistat.
Currently Available Weight Loss Medications
Phentermine (Adipex, Ionamin, Suprenza) and diethylpropion are the oldest medications for weight loss. Phentermine is available in daily doses of 37.5 mg, 30 mg,15 mg, and 8 mg (Lomaira). Phentermine is FDA-approved for short term use, and it is an adrenergic agonist that produces appetite suppression. Side effects include: dry mouth, insomnia, dizziness, and irritability. Caution should be used in patients with hypertension.
Orlistat is a weight loss pill that inhibits pancreatic and gastric lipase decreasing fat absorption in the gastrointestinal tract. It is available to be taken with meals in doses of 120 mg (Xenical) and 60 mg (Alli) OTC. Side effects include: flatulence with fatty discharge and fecal urgency after consumption of high-fat foods, side effects that lead to medication discontinuation.
Since 2012, the FDA has approved four safe weight loss medications for long-term weight management.
Lorcaserin (Belviq, Belviq XR) is a selective serotonin 5HT 2c receptor agonist that suppresses appetite. It is well tolerated but has modest weight loss results. Side effects include: headache, nausea, dizziness, euphoria, and impairment of attention-cognition. It is not recommended for patients taking other serotonin-modulating medications or those with known cardiac valvular disease.
Phentermine-Topiramate extended release (Qsymia) is the most effective weight loss drug available to date. It combines an adrenergic agonist with a neurostabilizer. Daily doses with four strengths start at 3.75/23mg to 15mg/92mg. Adults with migraines and obesity are good candidates for this weight loss medication. Side effects include: abnormal sensations, dizziness, taste alterations, insomnia, constipation, and dry mouth. Contraindications include: uncontrolled hypertension and coronary artery disease, hyperthyroidism, glaucoma, and sensitivity to stimulants. If more than 5% weight loss is not achieved after 12 weeks of the maximum dose, the weight loss pill should be gradually discontinued.
Bupropion/Naltrexone (Contrave) combines a dopamine/norepinephrine reuptake inhibitor and an opioid receptor antagonist. Start with a daily dose of 8/90 mg tablet to four tablets a day. It controls cravings and addicted behaviors related to food. Side effects include: constipation, headaches, insomnia, and dry mouth. Contraindications include: uncontrolled hypertension, history of seizures, and opioid use and dependence.
Liraglutide (Saxenda) is a glucagon-like peptide 1 (GLP-1) receptor approved for diabetes type 2 as Victoza and for weight loss injection as Saxenda. Doses start at 0.6 mg to 3 mg a day. Liraglutide delays gastric emptying and causes satiety. Good candidates are adults with diabetes and prediabetes. Side effects include: nausea, vomiting, diarrhea, constipation, and abdominal pain. It is contraindicated in patients with personal or family history of medullary thyroid carcinoma.
Obesity medications are intended for long-term use, as obesity is a chronic disease. They improve health, quality of life, and body weight in patients with overweight and obesity.
Medications for weight loss are only one component of a comprehensive treatment plan that also includes nutritional, physical activity, and behavioral therapies.
- Obesity Algorithm. 2017-2018. Obesity Medicine Association
- Saunders KH, Shukla AP, Igel LI, Aronne LJ. Obesity: When to consider medication. The Journal of Family Practice. 2017: 66:608-615.
- Diet, Drugs, Devices and Surgery for Weight Management. The Medical Letter, June 4 2018:60 (1548).
- Association of Pharmacological Treatments for Obesity With Weight Loss and Adverse Events: A Systematic Review and Meta-analysis. JAMA, 2016: 315(22):2424-2434.
This article was written by Doris Munoz-Mantilla, MD, FOMA. Dr. Munoz-Mantilla is an obesity medicine physician in Jupiter, FL. She discloses no financial affiliations with any of the pharmaceutical companies or products mentioned in this article.