Open-label pilot of lorcaserin (a serotonin 2C-receptor agonist) for cannabis use disorder

Background and ObjectiveCannabis Use Disorder (CUD) has no FDA-approved treatment. Serotonin-2c (5HT2c) agonists have preclinical and human laboratory evidence for their potential efficacy for CUD. We assessed the tolerability and effects of lorcaserin (5HT2c agonist) on CUD.MethodsIn a 10-week, open label, uncontrolled trial, the tolerability of lorcaserin was tested in outpatients with CUD. Adverse events (AE) were assessed weekly. Cannabis use was assessed twice weekly by the Timeline follow-back and quantitative urine metabolites.ResultsSeventeen participants enrolled, and 14 received medication. Participants' average age was 35 years; majority were male (N = 12). The medication was well tolerated in males. There were no serious adverse events (SAE). The most common AE's were headache/migraine (N = 4, all females), anorexia (N = 3), and irritability (N = 2). Participants decreased their frequency of cannabis use significantly (p < 0.001), adjusted for baseline use. By the end of the trial, participants decreased by 1.76 (SE = 0.47) cannabis using days/week. Average daily amount of cannabis and urine THC metabolite levels did not change significantly.ConclusionsLorcaserin was well tolerated in males but not females, suggesting possible sex differences. Future trials of other 5HT2c agonists (lorcaserin was withdrawn at the request of the FDA) should consider longer dose titration phases.