The study will compare Repetitive Transcranial Magnetic Stimulation (rTMS) with placebo rTMS in reducing Cocaine and/or Methamphetamine use. Study participants will be adults who currently use Cocaine and/or Methamphetamine. Eligible participants will receive multiple sessions of repetitive Transcranial Magnetic Stimulation (rTMS) or placebo rTMS over the course of an 8-week treatment period and will complete follow-up assessments for 8 weeks post-treatment. Participants will be compensated for participating.

This proposed project is to investigate the role of cocaine use in B cell dysfunctions and poor immune recovery from antiretroviral therapy in HIV.

This pilot study is to research whether or not the investigational drug clavulanic acid, along with medication management, can help people with cocaine use disorder who are interested in quitting. Participants who are eligible after screening visits are randomly assigned to take clavulanic acid or placebo for twelve weeks and will meet with study staff three times a week for urine drug screens.

HIV infected cocaine users have uncontrolled viral levels and impaired immunity to control infection compared to HIV infected non-drug users. We ask the questions why cocaine use makes HIV infected cocaine users more sick than other patients. The goal is to improve immunity to control HIV infection in cocaine users. Both uninfected cocaine users and HIV-infected cocaine users are especially needed in this study.