Lack of effects of ethanol pretreatment on the abuse liability of nitrous oxide in light and moderate drinkers.

Neither a history of light or moderate alcohol use nor acute doses of ethanol (0.35 or 0.7 g/kg) altered the abuse liability of 30% nitrous oxide in healthy light and moderate drinkers. Choice of nitrous oxide was similar across groups and ethanol doses, averaging about 3.3 out of 6 choices. Subjective effects like liking and desire to inhale the drug again were positively correlated with choice, but these effects were also unaffected by ethanol history or pretreatment. The findings suggest that, under these experimental conditions, ethanol does not modulate the reinforcing or subjective effects of nitrous oxide.

Study at a glance

Abstract

To determine effects of ethanol-use history and ethanol pretreatment on abuse liability of nitrous oxide (N(2)O). Placebo-controlled, double-blind, cross-over design evaluating effects of N(2)O, 0% (100% O(2), placebo) and 30% (in O(2)), in the presence of three doses of ethanol: 0 g/kg (placebo), 0.35 g/kg and 0.7 g/kg. Subjects sat in a reclining chair in a hospital laboratory. Eight healthy light drinkers (one drink or less/week) and eight healthy moderate drinkers (seven or more drinks/week) with no history of drug dependence completed the study. On three sessions (1, 3, 5) subjects drank a beverage that contained one of the three ethanol doses, then sampled for 10 minute each 0% and 30% N(2)O. During choice sessions (2, 4, 6), subjects received the same ethanol dose as in the previous session, then chose six times, once every 5 min, between 0% and 30% N(2)O. Subjective (self-reported) drug effects, reinforcing effects of N(2)O as assessed by choice, and psychomotor effects were measured. Choice of N(2)O did not differ between light (mean = 3.4 choices) and moderate (mean = 3.2 choices) drinkers and was not influenced by ethanol dose (0 g/kg: 3.3 choices, 0.35 g/kg: 3.5 choices, 0.7 g/kg: 3.1 choices). Subjective effects of N(2)O also did not depend on ethanol-use history or ethanol dose. N(2)O liking and desire to inhale the drug again were positively correlated with N(2)O choice. Ethanol pretreatment and ethanol-use history had no effect on the abuse liability of N(2)O as assessed in the present study.