Cocaine plasma concentration: relation to physiological and subjective effects in humans

Area of Science:

• Pharmacology
• Neuroscience
• Addiction Research

Background:

• Cocaine hydrochloride is a potent stimulant with significant abuse potential.
• Understanding cocaine pharmacokinetics is crucial for addiction treatment and harm reduction.
• Previous studies indicate dose-dependent effects, but route-specific pharmacokinetics require further elucidation.

Purpose of the Study:

• To investigate the relationship between cocaine hydrochloride plasma concentrations and physiological/subjective responses.
• To compare the pharmacokinetic profiles of intravenous versus intranasal cocaine administration.
• To determine the duration of drug effects in relation to plasma cocaine levels.

Main Methods:

• Volunteer subjects with prior cocaine use history participated.
• Cocaine hydrochloride was administered via intravenous and intranasal routes.
• Plasma concentrations, physiological measures (e.g., heart rate, blood pressure), and subjective effects were monitored.

Main Results:

• A positive correlation was observed between peak plasma cocaine concentration and both physiological and subjective responses.
• The decline in physiological and subjective effects after intravenous administration mirrored the rate of cocaine disappearance from plasma.
• Intranasal cocaine administration resulted in prolonged elevated plasma cocaine levels compared to intravenous administration.

Conclusions:

• Cocaine's physiological and subjective effects are directly related to plasma concentration.
• Intravenous administration leads to rapid onset and offset of effects, closely following plasma levels.
• Intranasal administration provides a slower absorption and longer duration of action, potentially influencing abuse liability and treatment strategies.