Cocaine dependence, particularly in combination with heroin dependence, poses serious and substantial public health, social, and economic problems (e.g., high medical costs, crime, lost productivity). Cocaine and heroin use disorders often co-occur, and this conjunction is associated with higher rates of medical and psychiatric problems and worse drug abuse treatment outcome.

Many medications have been tested, but have failed, for treating cocaine dependence alone or in cocaine abusers who also use heroin.

This clinical trial will test whether SR-AMP is more effective than placebo for preventing relapse to cocaine use, using SR-AMP for patients with only cocaine dependence, or in combination with buprenorphine (for those patients who are also dependent on heroin).

Participants will first be an outpatient and must come to the Jefferson Avenue Research Program three times per week (e.g. Monday, Wednesday, Friday) to measure drug use and drug-related symptoms. This phase will last at least 2 weeks.

Next, participants will live on an inpatient research unit at Detroit Receiving Hospital for seven (7) consecutive nights. During the weeklong inpatient stay, in addition to receiving SR-AMP or placebo capsules, participants will begin counseling treatment to help prepare to avoid relapse after they are discharged from the inpatient unit.

After the inpatient stay, participants will then be an outpatient and come to the Jefferson Ave. Research Program daily for eight (8) weeks. Throughout all eight weeks, three urine samples will be collected each week to assess illicit drug use, and questionnaires related to drug symptoms and to assess mood and risk behaviors will be given.