Reinforcing Effects of Cocaine During Phendimetrazine Maintenance

Inclusion Criteria: * Recent cocaine use Exclusion Criteria: * Abnormal screening outcome (e.g., ECG, blood chemistry result) that study physicians deem clinically significant * Current or past histories of substance abuse or dependence that are deemed by the study physicians to interfere with study completion * History of serious physical disease, current physical disease, impaired cardiovascular functioning, chronic obstructive pulmonary disease, history of seizure or current or past histories of serious psychiatric disorder that in the opinion of the study physician would interfere with study participation will be excluded from participation * Females not currently using effective birth control * Contraindications to cocaine or phendimetrazine