Gamma-hydroxybutyrate (GHB) produces dose-related changes in subjective effects, showing a mixed stimulant-sedative pattern: initial feelings of euphoria, high, and liking, followed by mild-to-moderate sedation with impaired performance and balance. Single oral doses of 40, 50, 60, and 72 mg/kg were given to eight volunteers. Mean peak plasma concentrations ranged from 79.1 to 130.1 μg/L. Physiological and subjective effects were dose-dependent and related to plasma concentrations. Urinary excretion was mainly related to dose. The results suggest high abuse liability at the doses typically consumed.
A single oral dose of gamma-hydroxybutyric acid (GHB) at 40 or 60 mg/kg produces euphoria and pleasurable effects with slightly higher ratings than those from flunitrazepam (1.25 mg) or ethanol (0.7 g/kg) in healthy male recreational club drug users. GHB shows a biphasic time profile: an initial stimulant-like effect as plasma concentrations rise, followed by a later sedative effect unrelated to its kinetics. GHB increases blood pressure and pupil diameter, while flunitrazepam produces marked sedation. Both GHB and flunitrazepam impair psychomotor performance, including digit symbol substitution and balance tasks, whereas ethanol only mildly affects balance. The findings suggest a high abuse liability of GHB and flunitrazepam in this population.