Cocaine
During three drug administration sessions, participants orally ingested, with water, a size 00 opaque capsule containing either 0 (placebo), 125 mg/70 kg, or 250 mg/70 kg of cocaine hydrochloride. Across sessions, the capsules appeared identical and were each filled completely with a combination of cellulose and/or cocaine hydrochloride. Drug administration was double-blind. Administration order was randomized across participants.