Intervention: Lorcaserin
Trial phase: Phase 2
ATC code: A08AA11
SMILES: C[C@H]1CNCCc2ccc(Cl)cc21
Sex: Male
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 16
Group description: lorcaserin, extended release

lorcaserin: lorcaserin 20 mg tablet
Eligibility criteria:
Inclusion Criteria:

Male gender assigned at birth and transgender men;
self-reported anal intercourse with men in the prior six months while under the influence of cocaine;
cocaine use disorder by (Diagnostic and Statistical Manual of Mental Health Disorders (DSM-V) and Structured clinical interviews (SCID) criteria;
current cocaine use confirmed by urinalysis and cocaine use at least 15 days in the past 30 days;
HIV-negative by rapid test or HIV-positive with a medical record of HIV infection;
no current acute illnesses requiring prolonged medical care;
no chronic illnesses that are likely to progress clinically during trial;
able and willing to provide informed consent and adhere to visit schedule;
age 18-65 years;
baseline complete blood count (CBC), total protein, albumin, glucose, alkaline phosphatase, creatinine, Blood Urea Nitrogen (BUN), and electrolytes without clinically significant abnormalities as determined by study clinician in conjunction with symptoms, physical exam, and medical history

Exclusion Criteria:

Any psychiatric condition (e.g., depression with suicidal ideation, schizophrenia) or medical condition that would preclude safe study participation;
HIV-positive test result at screening visit but previously unaware of HIV infection (i.e., newly diagnosed with HIV infection at screening; those with a medical record of HIV infection are eligible);
any moderate to severe alcohol or substance use disorders (other than cocaine use disorders), according to DSM-V criteria;
known allergy or previous adverse reaction to lorcaserin;
current T-cell count (CD4) count < 200 cells/mm3 ;
moderate/sever liver disease (Aspartate Transferase (AST), Alanine Transaminase (ALT) > 3 times upper limit or normal);
severely impaired renal function (creatinine clearance £ 30 ml/min);
use of medications that affect the serotonergic neurotransmitter system (e.g., selective serotonin reuptake inhibitors (SSRIs), selective serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs));
predisposition to priapism;
currently participating in another longitudinal intervention research study;
body mass index (BMI) < 15; or ≥ 30 with desire to use weight management medication, or BMI > 35;
anticipated use of agents that are associated with valvulopathy and/or pulmonary hypertension
Are currently treated with an opiate-substitute (buprenorphine or methadone) maintenance treatment or received therapy with any opiate-substitute within 30 days preceding screening
Currently in court-mandated cocaine use treatment;
Had previous history of suicidal behavior in the last 12 months ("yes" answer to the suicidal behavior question 6 of the Columbia-Suicide Severity Rating Scale (C-SSRS)); or currently have suicidal ideation as determined by 'yes' answers to questions 4 or 5 on the C-SSRS administered by a study clinician;
Any physical condition affecting drug absorption (e.g., gastrectomy);
12-lead Electrocardiogram (ECG) demonstrating Corrected QT interval (QTc) > 450 or a Q wave, R wave and S wave (QRS) interval > 120 msec at screening. If Fridericia (QTcF) exceeds 450 msec, or QRS exceeds 120 msec, the ECG should be repeated two more times and the average of the three QTc values should be used to determine the subject's eligibility.

(Note: Participants newly diagnosed with HIV at screening who consent to be contacted for re-screening will be called in the subsequent month, or later, depending on participant preference).