Lorcaserin represents a new serotonergic medication used as an adjunct to a reduced-calorie diet and increased physical activity treatment plan for chronic weight management in adult patients with an initial body mass index ≥ 30 kg/m 2 or in adult patients with an initial body mass index ≥ 27 kg/m 2 who have ≥ 1 comorbid condition associated with weight (eg, hypertension, dyslipidemia, or type 2 diabetes mellitus). In 2012, lorcaserin became the first obesity treatment medication to gain US Food and Drug Administration (FDA) approval since 1999. Lorcaserin is a centrally acting, selective serotonin C (5-HT2C) receptor full agonist that is associated with increased satiety and decreased food consumption in patients. The selectivity of lorcaserin for 5-HT2C receptors should reduce patient risk for the serious adverse complications that are associated with nonselective 5-HT agonist therapies, such as cardiac valvulopathy and pulmonary hypertension. The safety and efficacy of lorcaserin (10 mg twice daily) for ≥ 52 weeks has been evaluated in 3 separate Phase 3 trials. The primary outcome of patient weight loss in the 3 trials satisfied the FDA categorical benchmark but patient outcomes in the trials failed to achieve the FDA mean benchmark of patient weight loss. Secondary patient outcomes after lorcaserin therapy were favorable. Lorcaserin appears to be well tolerated in patients and the most common adverse events reported did not include serious complications. The incidence of FDA-defined valvulopathy in patients after 1 year of treatment was low and nonsignificant, but the statistical analysis of this safety endpoint was limited due to the small size of the study populations and high patient dropout rates. Continued post-marketing surveillance of patients taking lorcaserin is warranted.