Medical Weight Loss

Prescription drugs approved by the FDA for chronic weight management are listed below. The FDA has approved six of these drugs—orlistat (Xenical, Alli), phentermine-topiramate (Qsymia), naltrexone-bupropion (Contrave), liraglutide (Saxenda), semaglutide (Wegovy), and tirzepatide (Zepbound)—for long-term use. Four of these drugs are approved for adults and children ages 12 and older. Another approved drug, setmelanotide (IMCIVREE), is limited to people who have been diagnosed with one of four specific rare genetic disorders, which must be confirmed by genetic testing. You can keep taking these medications as long as you are benefiting from treatment and not experiencing serious side effects.

Some weight management medications that curb appetite, such as phentermine, are approved by the FDA only for a few weeks. Although some healthcare professionals prescribe them longer, only a few research studies have examined their safety and effectiveness for long-term use.

These medications have side effects, some of which could be severe. Before taking any medication to treat obesity, discuss the possible risks and benefits with your healthcare professional.

• Ask your healthcare professional if you have medical conditions that could increase your risk of developing health problems when taking weight-loss medications.
• Weight-loss medications may have harmful interactions with other medicines you are taking. Discuss any prescribed medications, over-the-counter medications, or herbal products you take. Do not combine weight-loss medications with other products intended for weight loss unless prescribed by a health care professional.
• People taking certain weight-loss medications have reported having suicidal thoughts or actions, and the FDA continues to look into whether the medication causes this.
• People who are pregnant or planning to become pregnant should not take weight-loss medications, as they may harm the fetus. Weight-loss medications are not recommended for people who are breastfeeding.
• Before taking a weight-loss medication, tell your doctor about any allergies or sensitivities.

Semaglutide (Wegovy, Ozempic)

Wegovy is a brand name for semaglutide, a GLP-1 receptor agonist. It was FDA approved in 2021. It is administered as an injection and approved for use in adults and children aged 12 years or more with obesity (BMI ≥30 for adults, BMI ≥ 95th percentile for age and sex for children) or some adults with excess weight (BMI ≥27) (overweight) who also have weight-related medical problems. The dose must be gradually increased over 16 to 20 weeks to reach the 2.4 mg dosage. This progression can help to alleviate side effects, which include gastrointestinal symptoms, headache, dizziness, and fatigue. Ozempic is the same medication but is approved to treat type 2 diabetes.

Tirzepatide (Zepbound, Mounjaro)

Tirzepatide was previously approved to treat type 2 diabetes as Mounjaro. As Zepbound, it is approved to treat obesity in adults with a BMI of 30 or greater. It is both a GLP-1 and a GIP receptor agonist and, like semaglutide, works by reducing appetite and is meant to be combined with diet and exercise to lose weight. It is also administered as an injection.

Liraglutide (Saxenda)

Liraglutide is a daily injectable medication that acts on hormones from the gut that send signals to the brain to make the patient feel full quickly and decrease hunger signals. Doses start at 0.6 mg to 3 mg a day. Some patients may lose 5–10% of their body weight, especially with a higher dose of liraglutide. Side effects include nausea, diarrhea, constipation, vomiting, headache, decreased appetite, dyspepsia, fatigue, dizziness, abdominal pain, increased lipase, and renal insufficiency. It is contraindicated in patients with personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2.

Phentermine (Adipex, Suprenza)

Phentermine is the oldest and most widely used weight loss medication. It was initially used as a short-term medication to jump-start weight loss, but now newer medical guidelines have added it to long-term therapy. Some patients may lose about 5% of their body weight by taking phentermine. In the US, phentermine is almost exclusively available in the HCl formulation, with 15 and 30 mg strength. Side effects include headache, overstimulation, high blood pressure, insomnia, rapid or irregular heart rate, and tremor. Interactions may occur during or within 14 days following monoamine oxidase (MAO) inhibitors, sympathomimetics, alcohol, adrenergic neuron-blocking drugs, and possibly some anesthetic agents.

Phentermine-topiramate (Qsymia)

Topiramate can be combined with phentermine to decrease appetite and cravings. Having the combination of two drugs increases efficacy. Adults with migraines and obesity are good candidates for this weight-loss medication. Some patients may lose an average of 5–10% of body weight. If more than 5% weight loss is not achieved after 12 weeks of the maximum dose, the weight loss pill should be gradually discontinued. Daily doses with four strengths start at 3.75 mg/23 mg to 15 mg/92 mg. Side effects include abnormal sensations, dizziness, altered taste, insomnia, constipation, and dry mouth. Contraindications include uncontrolled hypertension and coronary artery disease, hyperthyroidism, glaucoma, and sensitivity to stimulants.

Naltrexone-bupropion (Contrave)

Naltrexone-bupropion combines an opioid receptor antagonist with an antidepressant to affect the pleasure-reward areas of the brain and thereby decrease cravings and appetite. Some patients may lose 5–10% of body weight. Start with a daily dose of one 8/90 mg tablet and gradually increase to four daily tablets. The most common side effects include nausea, constipation, headache, vomiting, dizziness, insomnia, dry mouth, and diarrhea. This medication should not be prescribed to a patient who has a seizure disorder or who takes opioids for chronic pain.

Setmelanotide (Imcivree)
Setmelanotide is a melanocortin-4 receptor agonist indicated for chronic weight management in adult and pediatric patients six years of age and older with obesity due to one of several specific rare genetic disorders. The condition must be confirmed by genetic testing demonstrating variants in POMC, PCSK1, or LEPR genes interpreted as pathogenic, likely pathogenic, or of a variant of uncertain significance (VUS).

Orlistat (Xenical and Alli)

Orlistat is a lipase inhibitor that comes in a capsule and works by blocking the enzyme that breaks down fats consumed through food. In this way, it inhibits the absorption of dietary fats. The undigested fat is then passed through the body. It is intended for use with a reduced-calorie diet and is also indicated to reduce the risk of weight regain. Some patients may lose about 5% of their body weight. The dosage is one 120 mg capsule three times a day, with each main meal containing fat (during or up to 1 hour after the meal). An over-the-counter formulation is available in 60 mg capsules, with each meal that contains fat. The most common adverse reactions to orlistat are oily discharge from the rectum, flatus with discharge, increased defecation, and fecal incontinence.
Side effects and other reactions to weight management medications are possible. For more information, visit the FDA drug database.