Quick Takes: What You Need to Know About The 5 FDA-Approved Obesity Drugs

Scott Kahan, MD, MPH


March 02, 2017

Lorcaserin (Belviq®)

Type of drug/actions: Selective serotonin 2c (5HT-2c) receptor agonist; stimulates 5HT-2c receptors (not other serotonin receptors) in the appetite center of the brain.

Effects: Average weight loss 8%; improved blood pressure, lipids, glycemic control.

Dosing: 10 mg twice daily; does not require titration. Discontinue if the patient does not lose 5% of weight after 12 weeks.

Adverse effects: Headache, dizziness, fatigue, nausea, dry mouth, constipation; hypoglycemia with concomitant antidiabetic agents.

Precautions: Risk for serotonergic syndrome/neuroleptic malignant syndrome if the patient is taking serotonergic or antidopaminergic agent. Caution in patients with valvular heart disease, congestive heart failure, psychiatric disorders; priapism risk.

Contraindications: Pregnancy.

Naltrexone SR/Bupropion SR (Contrave®)

Type of drug/actions: Bupropion (a dopamine and norepinephrine reuptake inhibitor used to treat depression and smoking cessation) and naltrexone (an opioid receptor antagonist used to treat addiction). Effects may occur in the hypothalamic appetite center or the mesocorticolimbic dopamine system and other brain areas related to reward-driven behaviors.

Actions: Long-term use; combination produces > 8% weight loss (diminished appetite and cravings); > 12% weight loss when combined with intensive lifestyle intervention. Also improves glycemic control.

Dosing: Week 1: one pill (8 mg naltrexone/90 mg bupropion) daily; escalate weekly to target dose of two pills twice daily (total, 32/360 mg) by week 4. Evaluate response after 12 weeks on target dose; stop treatment if weight loss < 5%.

Adverse effects: Nausea, constipation, diarrhea, headache; most resolve in days to weeks and do not recur.

Precautions: Warning about suicidal thoughts in patients < 24 years.

Contraindications: Uncontrolled hypertension; seizure disorders; chronic opioid use; MAOI use; pregnancy.

Other considerations: May be a good choice for patients with comorbid depression, as well as those who wish to quit smoking.

Liraglutide 3.0 mg (Saxenda®)

Type of drug/actions: Glucagon-like peptide 1 receptor agonist.

Effects: Achieved 9% weight loss; 71% maintained at 3 years. Reduced progression to diabetes by 80%.

Dosing: Requires daily subcutaneous injection (abdomen, arm, or thigh; rotate injection site). Start with 0.6 mg; titrate by 0.6 mg/week for 5 weeks to target dose of 3.0 mg. Evaluate response after 16 weeks; stop treatment if weight loss < 4%.

Adverse effects: Nausea; gastrointestinal symptoms.

Precautions: Hypoglycemia can occur in patients on antidiabetic medications; may be severe in patients concomitantly treated with sulfonylureas or insulin.

Contraindications: History of medullary thyroid carcinoma, multiple endocrine neoplasia type 2, acute pancreatitis, pregnancy, breastfeeding.

Other considerations: May be a good choicer for patients with or at risk for diabetes or prediabetes and those unlikely to become pregnant.

An expanded discussion of the clinical trial findings and case studies in pharmacologic obesity management can be found in Using Anti-obesity Drugs: Which Drug for Which Patient?


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