Medications Approved by the FDA for Long-Term Use for Weight Management

Medication (Trade Names)Mechanism of ActionFive Most Common Side EffectsPossible Safety Concerns*Mean 1-Year Weight Loss Compared to Placebo (Dose)A1C Change in Patients With Diabetes (%)
Decreases absorption
Orlistat (Alli, Xenical)Lipase inhibitorAbdominal pain, flatulence, fecal urgency, back pain, and headacheFat-soluble vitamin deficiencies, altered absorption of medications, cholelithiasis, nephrolithiasis3.4 kg, 4.0% (120 mg TID)–0.7
Suppresses appetite
Lorcaserin (Belviq)Serotonin receptor agonistHeadache, nausea, dizziness, fatigue, and nasopharyngitisSerotonin syndrome, hypertension, edema, avoid in liver and renal failure3.3 kg, 3.6% (10 mg BID)–1.1
Phentermine/Topiramate (Qsymia)Norepinephrine release, GABA receptor modulationConstipation, paresthesia, insomnia, nasopharyngitis, and xerostomiaBirth defects, cognitive impairment, acute angle-closure glaucoma, lactic acidosis with metformin, avoid in renal failure6.7 kg, 6.6% (7.5/46 mg daily) 8.9 kg, 9.0% (15/92 mg daily)–0.4
Naltrexone/Bupropion (Contrave)Opiate antagonist, decreased re-uptake of norepinephrineConstipation, nausea, headache, xerostomia, and insomniaDepression, anxiety, acute angle-closure glaucoma, avoid in patients with uncontrolled hypertension and renal failure4.1 kg, 5.2% (16/80 mg BID)–0.6
Liraglutide (Saxenda)GLP-1 receptor agonistHypoglycemia, constipation, nausea, headache, and indigestionGastroparesis, suicidal ideation, increased heart rate, caution in pancreatitis and cholelithiasis4.5 kg, 5.6% (3 mg daily)–0.6 to –1.8
  • * A comprehensive list of safety concerns can be found in each medication’s package insert, which is available from the manufacturing pharmaceutical company.

  • A1C change has only been assessed in patients with prediabetes (66).

  • BID, twice daily; GABA, gamma-aminobutyric acid; TID, three times daily.