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LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-.

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LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet].

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Last Update: May 20, 2019.



Lorcaserin is a selective serotonin agonist that is approved as a weight loss agent. Lorcaserin has been in clinical use for a short time only, but has not been linked to serum enzyme elevations during therapy or to instances of clinically apparent liver injury.


Lorcaserin (lor ka' ser in) is a serotonin agonist that is relatively selective for the serotonin 2C (5-HT2C) receptor, that is located almost exclusively in the brain. Activation of this receptor activates pathways important in hunger and satiety, including those that induce proopiomelanocortin which decreases appetite. In several premarketing controlled trials, lorcaserin was found to lead to greater weight loss than placebo. Lorcaserin was officially approved for use in the United States in 2012, but was recommended only for patients who are obese (BMI ≥30) or who are overweight (BMI ≥27-30) and have a significant obesity related condition. Lorcaserin is available in 10 mg tablets under the commercial name Belviq. The recommended dose is 10 mg twice daily. An extended release formulation, available as 20 mg tablets (Belviq XR), has been developed which is administered once daily. Commonly reported side effects are headache, dry mouth, nausea, fatigue and dizziness which rarely require discontinuation or dose adjustment. Severe side effects are rare and possibly included depression, serotonin syndrome and cardiac valvulopathy, although side effects were not appreciably increased among lorcaserin treated patients in pre-licensure clinical trials.


In premarketing clinical trials, serum aminotransferase elevations were no more common among patients receiving lorcaserin than placebo. Clinically apparent liver injury due to lorcaserin has not been reported, but the numbers of patients treated has been limited.

Likelihood score: E (unlikely cause of clinically apparent liver injury).

Outcome and Management

No instances of acute liver failure or chronic liver injury have been linked to lorcaserin, but it has had limited general clinical use.

Drug Class: Weight Loss Agents



Lorcaserin – Belviq®


Weight Loss Agents


Product labeling at DailyMed, National Library of Medicine, NIH


Lorcaserin Chemical Structure


References updated: 20 May 2019

  • Zimmerman HJ. Hepatotoxicity: the adverse effects of drugs and other chemicals on the liver. 2nd ed. Philadelphia: Lippincott, 1999.
    (Review of hepatotoxicity published in 1999, well before the availability of lorcaserin).
  • Smith SR, Prosser WA, Donahue DJ, Morgan ME, Anderson CM, Shanahan WR; APD356-004 Study Group. Lorcaserin (APD356), a selective 5-HT (2C) agonist, reduces body weight in obese men and women. Obesity (Silver Spring) 2009; 17: 494-503. [PubMed: 19057523]
    (Randomized controlled trial of 12 weeks of lorcaserin vs placebo in 469 obese subjects; no mention of ALT levels or hepatotoxicity).
  • Smith SR, Weissman NJ, Anderson CM, Sanchez M, Chuang E, Stubbe S, Bays H, Shanahan WR; Behavioral Modification and Lorcaserin for Overweight and Obesity Management (BLOOM) Study Group. Multicenter, placebo-controlled trial of lorcaserin for weight management. N Engl J Med 2010; 363: 245-56. [PubMed: 20647200]
    (Randomized controlled trial of 52 weeks of twice daily lorcaserin vs placebo in 3182 obese or overweight patients; serious adverse events included "hepatobiliary disorder" in 0.3% of lorcaserin and 0.3% of placebo recipient; no mention of ALT levels and no clinical details given).
  • Astrup A. Drug management of obesity--efficacy versus safety. N Engl J Med 2010; 363: 288-90. [PubMed: 20647205]
    (Editorial in response to Smith [2010] reviewing history of weight loss agents used in the United States, many having been withdrawn because of issues of safety of long term use).
  • Hurren KM, Berlie HD. Lorcaserin: an investigational serotonin 2C agonist for weight loss. Am J Health Syst Pharm 2011; 68: 2029-37. [PubMed: 22011982]
    (Review of safety and efficacy of lorcaserin for weight loss based upon 3 phase III trials; most common side effects were nausea [8.3%], headache [16.8%], and dizziness [8.5%], but discontinuations for side effects were rare; no mention of ALT levels or hepatotoxicity).
  • Fidler MC, Sanchez M, Raether B, Weissman NJ, Smith SR, Shanahan WR, Anderson CM; BLOSSOM Clinical Trial Group. A one-year randomized trial of lorcaserin for weight loss in obese and overweight adults: the BLOSSOM trial. J Clin Endocrinol Metab 2011; 96: 3067-77. [PubMed: 21795446]
    (Randomized controlled trial of two doses of lorcaserin vs placebo for an average of 20 weeks in 4008 obese or overweight patients: "No lorcaserin-associated changes in clinical laboratory parameters... were identified").
  • O'Neil PM, Smith SR, Weissman NJ, Fidler MC, Sanchez M, Zhang J, Raether B, et al. Randomized placebo-controlled clinical trial of lorcaserin for weight loss in type 2 diabetes mellitus: the BLOOM-DM study. Obesity (Silver Spring) 2012; 20: 1426-36. [PubMed: 22421927]
    (Randomized controlled trial of lorcaserin vs placebo in 604 overweight or obese patients with diabetes; no mention of ALT levels or hepatotoxicity).
  • Chan EW, He Y, Chui CS, Wong AY, Lau WC, Wong IC. Efficacy and safety of lorcaserin in obese adults: a meta-analysis of 1-year randomized controlled trials (RCTs) and narrative review on short-term RCTs. Obes Rev 2013; 14: 383-92. [PubMed: 23331711]
    (Systematic review of results from 5 randomized controlled trials of lorcaserin, only 3 of which used the agent for more than 12 weeks; no mention of hepatotoxicity or ALT elevations).
  • Nigro SC, Luon D, Baker WL. Lorcaserin: a novel serotonin 2C agonist for the treatment of obesity. Curr Med Res Opin 2013; 29: 839-48. [PubMed: 23574263]
    (Review of the mechanism of action, efficacy and safety of lorcaserin as therapy of obesity; no mention of liver injury or ALT elevations).
  • Yanovski SZ, Yanovski JA. Long-term drug treatment for obesity: a systematic and clinical review. JAMA 2014; 311: 74-86. [PMC free article: PMC3928674] [PubMed: 24231879]
    (Systematic review of the long term efficacy of drug therapies for obesity including lorcaserin, orlistat and phentermine plus topiramate).
  • Lorcaserin. In obesity: unacceptable risks. Prescrire Int 2014; 23: 117-20. [PubMed: 24926508]
    (Review of the efficacy and safety of lorcaserin concludes that its weight loss effects are minimal and short-lived, and that its costs and risks of adverse events do not warrant its use as therapy of obesity).
  • Halpern B, Halpern A. Safety assessment of FDA-approved (orlistat and lorcaserin) anti-obesity medications. Expert Opin Drug Saf 2015; 14: 305-15. [PubMed: 25563411]
    (Review of the safety and efficacy of FDA approved medications for obesity including lorcaserin).
  • Chalasani N, Bonkovsky HL, Fontana R, Lee W, Stolz A, Talwalkar J, Reddy KR, et al.; United States Drug Induced Liver Injury Network. Features and outcomes of 899 patients with drug-induced liver injury: The DILIN Prospective Study. Gastroenterology 2015; 148: 1340-52.e7. [PMC free article: PMC4446235] [PubMed: 25754159]
    (Among 899 cases of drug induced liver injury enrolled in a US prospective study between 2004 and 2013, none of the cases were attributed to a weight loss product such as lorcaserin).
  • Smith SR, Garvey WT, Greenway FL, Zhou S, Fain R, Pilson R, Fujioka K, et al. Coadministration of lorcaserin and phentermine for weight management: A 12-week, randomized, pilot safety study. Obesity (Silver Spring) 2017; 25: 857-65. [PMC free article: PMC5518190] [PubMed: 28440045]
    (Among 235 overweight or obese, non-diabetic adults treated with lorcaserin alone or wiht phentermine [once or twice daily], weight loss was greater with the combination but so were side effects, but "there was no evidence of hepatic or renal toxicity").
  • Bohula EA, Scirica BM, Inzucchi SE, McGuire DK, Keech AC, Smith SR, Kanevsky E, et al; CAMELLIA-TIMI 61 Steering Committee Investigators. Effect of lorcaserin on prevention and remission of type 2 diabetes in overweight and obese patients (CAMELLIA-TIMI 61): a randomised, placebo-controlled trial. Lancet 2018; 392 (10161): 2269-79. [PubMed: 30293771]
    (Among 12,000 overweight or obese adults treated with lorcaserin or placebo for a median of 3.3 years, weight loss was greater with lorcaserin by approximately 2.6 kg; no mention of ALT elevations or other adverse events).
  • Bohula EA, Wiviott SD, McGuire DK, Inzucchi SE, Kuder J, Im K, Fanola CL, et al; CAMELLIA–TIMI 61 Steering Committee and Investigators. Cardiovascular safety of lorcaserin in overweight or obese patients. N Engl J Med 2018; 379: 1107-17. [PubMed: 30145941]
    (Further analysis of trial of lorcaserin in 12,000 overweight or obese adults focusing upon safety and adverse events mentions adverse events "possible" to include dizziness, fatigue, headache, diarrhea and nausea; no mention of ALT elevations or hepatotoxicity).
  • Diet, drugs, devices, and surgery for weight management. Med Lett Drugs Ther 2018; 60 (1548): 91-8. [PubMed: 29913463]
    (Concise review of the medical and surgical therapies for obesity mentions that lorcaserin is a schedule IV controlled substance and only modestly effective for weight loss and that adverse effects include headache, nausea, dizziness, euphoria and impairment of attention and cognition and possibly serotonin syndrome and cardiac valvulopathy; no mention of ALT elevations or hepatotoxicity).
  • Tuccinardi D, Farr OM, Upadhyay J, Oussaada SM, Mathew H, Paschou SA, Perakakis N, et al. Lorcaserin treatment decreases body weight and reduces cardiometabolic risk factors in obese adults: A six-month, randomized, placebo-controlled, double-blind clinical trial. Diabetes Obes Metab 2019; 21: 1487-92. [PMC free article: PMC6504613] [PubMed: 30724455]
    (Among 48 obese adults treated with lorcaserin or placebo for 6 months, weight loss was greater with lorcaserin [-2 vs -0.4 kg] as were decreases in hepatic fat index, while ALT and AST levels were normal and remained normal with therapy).


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