Dextro-amphetamine sulfate is a central nervous system stimulant that increases the release of the neurotransmitter dopamine in the brain. The purpose of this study is to further examine dose ranges of dextro-amphetamine sulfate as a treatment for cocaine dependence.

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.

Inclusion Criteria:

• DSM-IV diagnosis of cocaine dependence, as determined by the Structured Clinical Interview for DSM-IV
• Agreement to use an adequate method of contraception for the duration of the study
• Electrocardiogram confirmation by a cardiologist
• Cocaine-positive urine test prior to study entry

Exclusion Criteria:

• High blood pressure
• Significant heart disease
• Clinically significant cardiovascular abnormality
• Angina
• Kidney, liver, or gastrointestinal disorder
• Current Axis I disorder not related to drug use
• Current dependence on any drug other than nicotine
• Attention deficit disorder (ADD) or attention deficit hyperactivity disorder (ADHD)
• On probation or parole for reasons other than those related to drug abuse charges
• Pregnant or breastfeeding
• Sought treatment for drug dependence within 3 months prior to study entry
• Currently taking prescribed medications