Written on May 23, 2023 by Sendra Yang, PharmD, MBA. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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Over 40% of United States adults are obese, and more than two-thirds are considered overweight, based on data from the Centers for Disease Control and Prevention (CDC). Obesity is a common chronic disease impacting overall health and healthcare costs, and it is a contributing factor to serious health conditions such as heart disease, stroke, type 2 diabetes, and certain types of cancer.[2,3] The annual estimated medical cost of obesity was close to $173 billion in 2019.
Many people start their weight loss journey every year. Almost half of US adults have tried to lose weight in the last year. Losing 5% to 10% of your total body weight can positively improve blood pressure, cholesterol, and glucose levels. Therapies for obesity can include lifestyle changes, diet modifications, increased physical activity, medications, and in some cases, surgery. Medication options are gaining in popularity, making it even more important to understand how to manage weight loss drug side effects.
Weight loss medications and drug classes
The recommendation to add a medication to a weight loss plan includes a history of failing to achieve and maintain a weight loss of more than 5% of total body weight in the overweight or obese. Weight loss medications are generally used with lifestyle change support. Here are seven weight loss drugs that have been approved by the US Food and Drug Administration (FDA) for use in treating overweight and obesity.[6-8]
- Phentermine (Adipex-P®): Phentermine is part of the sympathomimetic amines drug class used short-term (up to 12 weeks) for weight loss with diet and exercise in obese and overweight people.[7,9] Sympathomimetic amine medications work by binding to hypothalamic receptors to stimulate epinephrine release and reduce hunger.
- Orlistat (Alli®): Orlistat is a lipase inhibitor and studies show its use results in an average weight loss of 2.5 to 3.2 kg in 1-4 years. It is used for weight loss in overweight adults with diet and exercise.
- Lorcaserin (Belviq XR®): Lorcaserin is in the serotonin 2C receptor agonist drug class. The serotonin receptors are found mainly in the brain and help to reduce appetite.[7,11] The medication should be discontinued if a 5% or more weight loss is not seen within 12 weeks.
- Bupropion-naltrexone (Contrave®): Bupropion and naltrexone is a combo medication with an opioid receptor antagonist (naltrexone) and a selective serotonin reuptake inhibitor (bupropion). Bupropion stimulates neurons in the hypothalamus to decrease appetite and is enhanced by naltrexone. The medication should be discontinued if weight loss of 5% or more is not seen within 12 weeks.
- Phentermine-topiramate (Qsymia®): Phentermine and topiramate is a combination drug consisting of a sympathomimetic amine (phentermine) and topiramate originally approved for epilepsy and migraine headache prevention. Topiramate is not used alone for weight loss therapy.
- Liraglutide (Saxenda®): Liraglutide is the first glucagon-like peptide-1 (GLP-1) receptor agonist approved by the US FDA for weight loss in overweight and obesity.
- Semaglutide (Wegovy®): Semaglutide is also a GLP-1 receptor agonist indicated for weight loss in overweight and obese individuals and is the first oral option in the GLP-1 class.
Weight loss common side effects based on drug class
Weight loss medications and drug classes work differently and have various side effects. Common side effects based on drug classes are [6,8]:
- Sympathomimetic amines: Anxiety, tachycardia, hypertension, xerostomia, insomnia, and constipation
- Lipase inhibitors: Oily spotting, flatus, fecal urgency and incontinence, abdominal discomfort
- Serotonin 2C receptor agonist: Common side effects include nausea, dizziness, and headache
- Combinations (based on the individual drugs): Dysgeusia, xerostomia, insomnia, paresthesia, constipation, headache, dizziness, nausea, and vomiting
- GLP-1 receptor agonist: Diarrhea, constipation, nausea, vomiting, dyspepsia, fatigue, dizziness, abdominal pain, anorexia, hypoglycemia
How to manage drug side effects
Managing side effects in weight loss medications is part of a comprehensive approach to weight loss plans. You can experience different adverse effects based on the medication class recommended to you by your healthcare provider. General factors to consider when managing drug side effects include the following :
- Consult with your healthcare provider on the potential side effects of the weight loss drug that is recommended for you.
- Adhere to the instructions on how to take the medication.
- Familiarize yourself with the common side effects so you know what to look for.
- Adjust the dose and timing of the drug, in consultation with your healthcare provider
- Regularly monitor and follow up with your healthcare provider so they can help assess how the medication is working for you.
- Report any concerns you have with your weight loss drug to your healthcare provider. If you experience any side effects, promptly notify your clinician so they can help take appropriate action, including discontinuation of the medication if warranted.
Weight loss with Everlywell
Everlywell offers you access to a telehealth option for online weight loss. You can get one-on-one assistance from a certified clinician for lifestyle support and medication recommendations, if appropriate. Medication and virtual clinical support can assist you in losing weight and reduce the risk of long-term health conditions. Losing weight is hard, but with the proper help, you can reach your weight loss goals and achieve overall health.
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- FastStats - overweight prevalence. Centers for Disease Control and Prevention. https://www.cdc.gov/nchs/fastats/obesity-overweight.htm. Published January 5, 2023. Accessed May 15, 2023.
- About overweight and obesity. Centers for Disease Control and Prevention. https://www.cdc.gov/obesity/about-obesity/index.html. Published February 24, 2023. Accessed May 15, 2023.
- Adult obesity facts. Centers for Disease Control and Prevention. https://www.cdc.gov/obesity/data/adult.html. Accessed May 15, 2023.
- Attempts to lose weight. Centers for Disease Control and Prevention. NCHS data briefs - number 313. July 12, 2018. https://www.cdc.gov/nchs/products/databriefs/db313.htm. Accessed May 15, 2023.
- Losing weight. Centers for Disease Control and Prevention. https://www.cdc.gov/healthyweight/losing_weight/index.html. Published September 19, 2022. Accessed May 15, 2023.
- Bray GA, Frühbeck G, Ryan DH, Wilding JP. Management of obesity. Lancet. 2016;387(10031):1947-56. doi: 10.1016/S0140-6736(16)00271-3. https://pubmed.ncbi.nlm.nih.gov/26868660/.
- Mordes JP, Liu C, Xu S. Medications for weight loss. Curr Opin Endocrinol Diabetes Obes. 2015;22(2):91-7. doi: 10.1097/MED.0000000000000140. https://pubmed.ncbi.nlm.nih.gov/25692921/.
- Pros and cons of weight-loss drugs. Mayo Clinic. October 29, 2022. https://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/weight-loss-drugs/art-20044832. Accessed May 15, 2023.
- DailyMed - ADIPEX-P®- phentermine hydrochloride tablet ADIPEX-P®- phentermine hydrochloride capsule. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f5b2f9d8-2226-476e-9caf-9d41e6891c46. Accessed May 15, 2023.
- DailyMed - Alli®- Orlistat capsule. U.S. National Library of Medicine. https://www.dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a2d3bd73-f3af-4ea5-a57c-66b0004cfe4f. Accessed May 15, 2023.
- DailyMed - Belviq XR® extended release extended release- lorcaserin hydrochloride tablet, film coated, extended release. U.S. National Library of Medicine. https://www.dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5b42e05f-33dd-49a0-ae24-a316f07a4b8d.Accessed May 15, 2023.
- FDA approves new drug treatment for Chronic Weight Management, first since 2014. U.S. Food and Drug Administration. https://www.fda.gov/news-events/press-announcements/fda-approves-new-drug-treatment-chronic-weight-management-first-2014. Accessed May 15, 2023.
- Learning about side effects. U.S. Food and Drug Administration, Center for Drug Evaluation and Research. https://www.fda.gov/drugs/information-consumers-and-patients-drugs/finding-and-learning-about-side-effects-adverse-reactions. Accessed May 15, 2023.