The effects of escalating doses of smoked cocaine in humans

This study examined the effects of escalating doses of smoked cocaine in non-treatment-seeking cocaine users. Cocaine sessions were conducted twice per day for 3 consecutive days. During each session, one group of participants smoked a 12 mg cocaine dose, followed by a 25 mg dose, followed by four 50 mg doses at 14 min intervals (escalating-dose group); another group of participants smoked six 50 mg cocaine doses at 14 min intervals (fixed-dosing group). Cocaine produced dose-dependent increases in heart rate (HR), blood pressure, ratings of positive drug effect, e.g., "good drug effect", and ratings of cocaine dose, e.g., "liking", in the escalating-dose group. The 50 mg dose also increased these measures in the fixed-dosing group to a level that was not different than that observed following the initial 50 mg dose in the escalating-dose group. The largest effects of 50 mg cocaine were observed following the initial dose, with the latter 50 mg doses maintaining but not increasing these effects in both groups. The effects of cocaine in both groups were consistent for most measures within a day and between days. Resting baseline heart rate, blood pressure and cocaine craving were lower during the first session and higher thereafter. These results demonstrate that increasing the dose of cocaine during a bout, i.e., "binge", of cocaine use can increment the effects of cocaine, but administering the same cocaine dose maintains, but does not increment the effects of cocaine. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.