Clinical pharmacokinetics of lofexidine, the alpha 2-adrenergic receptor agonist, in opiate addicts plasma using a highly sensitive liquid chromatography tandem mass spectrometric analysis.
OBJECTIVES
The objective of this investigation was to characterize the pharmacokinetic profile of lofexidine. Lofexidine is an orally bioavailable alpha 2-adrenergic receptor agonist analogue of clonidine that acts centrally to suppress opiate withdrawal symptoms.


METHODS
During the detoxification period of a phase 3 placebo-controlled, randomized, double-blind trial, six subjects were entered in this preliminary pharmacokinetic study.


RESULTS
Pharmacokinetic analysis of plasma samples collected during study day 7 indicated that C(max) was 3242 +/- 917 ng/L. The mean trough levels between the study days were not significantly different (p > .05), suggesting that the subjects were at steady-state.


CONCLUSIONS
Although preliminary due to the limited number of subjects, these findings are the first to document lofexidine clinical pharmacokinetics in opiate addicts using a highly sensitive liquid chromatography tandem mass spectrometric analysis.