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Lorcaserin is a selective serotonin agonist that has been recently 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 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.  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 included depression, serotonin syndrome and cardiac valvulopathy, which was 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.


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


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Lorcaserin – Belviq®


Weight Loss Agents



Product labeling at DailyMed, National Library of Medicine, NIH


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Lorcaserin 616202-92-7 C11-H14-CI-N Lorcaserin Chemical Structure


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References updated: 20 February 2014


  1. 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).

  2. 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 Citation  (Randomized controlled trial of 12 weeks of lorcaserin vs placebo in 469 obese subjects; no mention of ALT levels or hepatotoxicity).

  3. 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 Citation  (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).

  4. Astrup A. Drug management of obesity--efficacy versus safety. N Engl J Med 2010; 363: 288-90. PubMed Citation  (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).

  5. Hurren KM, Berlie HD. Lorcaserin: an investigational serotonin 2C agonist for weight loss. Am J Health Syst Pharm 2011; 68: 2029-37. PubMed Citation  (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).

  6. 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 Citation  (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").

  7. 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 Citation  (Randomized controlled trial of lorcaserin vs placebo in 604 overweight or obese patients with diabetes; no mention of ALT levels or hepatotoxicity).

  8. 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 Citation  (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).

  9. 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 Citation  (Review of the mechanism of action, efficacy and safety of lorcaserin as therapy of obesity; no mention of liver injury or ALT elevations).

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  1. PubMed logoRecent References on Lorcaserin

  2. Clinical Trials logoTrials on Lorcaserin

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