Physiological, subjective and reinforcing effects of oral and intravenous cocaine in humans.
BACKGROUND
There is little comparative information on the qualitative similarity, relative potency and reinforcing effects of oral cocaine versus cocaine administered via other routes.


METHODS
The present study used a within-subject, double-blind, double-dummy design to compare the physiological, subjective and reinforcing effects of placebo and oral (62.5, 125, 250 mg/70 kg) and intravenous (IV) (12.5, 25, 50 mg/70 kg) cocaine in volunteers with histories of cocaine abuse.


RESULTS
Cocaine produced dose-dependent increases on heart rate and blood pressure, with effects lasting longer after oral than IV cocaine. Subjective ratings (e.g., "rush," "drug effect," "liking") were qualitatively similar and dose-dependently increased after oral and IV administration, and the duration of effects was similar under both routes. On a money versus drug choice measure of reinforcement, the monetary amounts at which participants chose drug over money increased as a function of cocaine dose under both routes of administration. At doses that produced comparable subjective, physiological, and reinforcing effects, oral cocaine was not identified as cocaine as frequently as IV cocaine. Across measures, the data suggested that IV cocaine was approximately 10 times more potent than oral cocaine.


CONCLUSIONS
Overall, the results of this study support qualitatively similar effects of oral and IV cocaine and suggest that oral cocaine may be an effective tool for studying cocaine's effects in human laboratory studies.
Smith
B J
BJ
Department of Psychiatry and Behavioral Science, Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Suite 3000, Baltimore, MD 21224, USA. smithbrandi@missouri.edu
Jones
H E
HE
Griffiths
R R
RR
D000284:Administration, Oral; D000328:Adult; D000339:Affect / Q000187:drug effects* / Q000502:physiology; D000704:Analysis of Variance; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D003042:Cocaine / Q000008:administration & dosage*; D019970:Cocaine-Related Disorders / Q000523:psychology; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D012054:Reinforcement, Psychology
D018765:Dopamine Uptake Inhibitors; D003042:Cocaine