Discriminative stimulus, self-reported and cardiovascular effects of orally administered cocaine in humans.
This study evaluated whether an oral dose of cocaine can serve as a discriminative stimulus in humans. Four male and one female cocaine-abusing volunteers (ages 26-41 years) were trained to discriminate between cocaine HCl (80 mg/70 kg p.o.) and placebo. Once the criterion for discrimination was met (i.e., > or = 80% correct responding for four consecutive sessions), dose-effect curves were determined for orally administered cocaine (20, 40, 80 and 120 mg/70 kg), intranasally administered cocaine (20, 40, 80 and 120 mg/70 kg) and the benzodiazepine triazolam (0.25 and 0.50 mg/70 kg p.o.). All five subjects met the criterion for the cocaine-placebo discrimination within four to seven sessions. Novel cocaine doses by either the oral or intranasal route of administration generally produced dose-related increases in cocaine-appropriate responding, whereas triazolam produced predominantly placebo-appropriate responding. Cocaine by both routes produced qualitatively similar increases in stimulant-like self-reports, blood pressure and heart rate, whereas triazolam produced increases in sedative-like ratings and no changes in cardiovascular measures. Throughout dose-effect curve determinations, the training dose of cocaine and placebo continued to be identified correctly in four of five subjects (range, 75-100% correct responding). These results suggest that orally administered cocaine (80 mg/70 kg) is discriminable from placebo, has behavioral effects that are qualitatively similar to intranasal cocaine and does not show cross-generalization to a pharmacologically dissimilar compound.
Oliveto
A H
AH
Division of Substance Abuse, Connecticut Mental Health Center, Yale School of Medicine, New Haven.
Rosen
M I
MI
Woods
S W
SW
Kosten
T R
TR
D000281:Administration, Intranasal; D000284:Administration, Oral; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D003042:Cocaine / Q000008:administration & dosage*; D004193:Discrimination Learning / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D014229:Triazolam / Q000494:pharmacology
D014229:Triazolam; D003042:Cocaine