CONCURRENT PHARMACOKINETIC ANALYSIS OF PLASMA COCAINE AND ADRENOCORTICOTROPIC HORMONE IN MEN

The purpose of this study was to determine the covariance between plas ma cocaine and ACTH pharmacokinetics. Twelve healthy male occasional c ocaine users participated in a double blind study. Intravenous cocaine (0.2 mg/kg) or placebo was infused over 1 min, and samples for cocain e, ACTH and cortisol analysis were collected at 2, 4, 8, 12, 16, 20, 3 0, 40, 60, 80, 120, 180, and 240 min. Peak cocaine plasma levels avera ged 101.2 +/- 14.6 ng/mL. ACTH increases were significantly correlated (P < 0.0001) with increases in plasma cocaine levels (r = 0.67; r(2) = 0.44). Pharmacokinetic analysis showed that the t(max) (observed tim e to maximum concentration) values for cocaine (6.0 +/- 1.4 min) and A CTH (7.3 +/- 1.2 min) were almost identical. The area under the curve was calculated using the trapezoidal rule. The area under the curve fo r plasma cocaine was 6463 +/- 1070 ng/min.mL, and the area under the c urve for ACTH was 1873 +/- 188 pmol/min.L. The mean half-life for plas ma cocaine was 46.7 +/- 4.0 min, and that for ACTH was 35.8 +/- 5.1 mi n. Cardiovascular and subjective effect measures were correlated with concurrent increases in plasma cocaine and ACTH levels.