The primary goal of the study is to estimate the difference, if one exists, between XR-NTX and BUP-NX in the distribution of the time to relapse (i.e.., loss of persistent abstinence) during the 6-month trial. Secondary objectives are to: (1) compare outcome on XR-NTX versus BUP-NX across a range of clinical safety and secondary efficacy domains, and (2) explore demographic and, clinical, and genetic predictors of successful treatment and moderators of differential effectiveness (i.e., what variables may help clinicians choose which of these treatments is best for a given patient), and (3) collect a limited dataset to permit analyses of economic costs and benefits of the two treatments. The study is conducted in 8 NIDA Clinical Trials Network affiliated community based treatment programs. Up to 600 eligible participants will be randomized to treatment with XR-NTX or BUP-NX for 24 weeks (sufficient to include 350 participants who are randomized more than 72 hours after their last opioid).

The primary study objective is to assess the safety of disulfiram as a putative cocaine treatment agent by increasing our understanding of how disulfiram alters the cocaine response and how the addition of small doses of ethanol may alter this cocaine response. Satisfaction of this objective is required before the FDA will consider approval of further clinical trials with disulfiram treatment for cocaine dependence.

The primary aims of this study are to determine if there are significant safety interactions between oral modafinil and intravenous methamphetamine. Safety will be assessed by measuring adverse events and cardiovascular responses of heart rate (HR), blood pressure (BP), and electrocardiogram (ECG) and stroke distance (ICG).

The primary objective of this study is to assess the efficacy of cabergoline in reducing cocaine use in subjects with cocaine dependence (DSM-IV criteria). The hypothesis is that cabergoline will increase the weekly mean proportion of cocaine non-use days over the treatment period as compared to placebo as determined by self-report of cocaine use confirmed with urine assays for BE.

The primary outcome measure is the Modified Himmelsbach Opiate Withdrawal Scale (MHOWS), an objective assessment of the severity of opiate withdrawal symptoms, obtained on the second opiate detoxification day. It is hypothesized that the MHOWS scores will be significantly lower in the lofexidine as compared with the placebo group. Subjects will be medically discharged on the morning of the 11th day.