This randomized, double-blind dose study will compare the effectiveness of three active medication doses of dextro-amphetamine sulfate to placebo in the treatment of cocaine dependence. Participants will be randomly assigned to one of the four following dosages of dextro-amphetamine sulfate: 0 mg, 40 mg, 60 mg, or 80 mg. Participants will undergo a 2-week stabilization period followed by a 25-week study period. The study period will include administration of the stable medication dose for 21 weeks, followed by 1 week of dose reduction, and then 3 weeks without medication. All participants will receive weekly cognitive behavioral therapy and electrocardiograms. Participants will be given the option to participate in a voluntary plasma blood draw during Weeks 4, 8, and 20 and will be scheduled for follow-up assessments at Months 1 and 3 post-treatment.
