Comparison of Subjective Responses to Oral and Intravenous Alcohol Administration under Similar Systemic Exposures

Abstract

Objective To test whether an individual's subjective responses to alcohol are similar when the breath alcohol concentration (BrAC) trajectory resulting from oral administration is matched by intravenous administration. Background Individuals perceive the effects of alcohol differently, and the variation is commonly used in research assessing the risk for developing an alcohol use disorder. Such research is supported by both oral and intravenous alcohol administration techniques, and any differences attributable to the route employed should be understood. Methods We conducted a 2‐session, within‐subject study in 44 young adult, healthy, non‐dependent drinkers (22 females and 22 males). In the first session, subjects ingested a dose of alcohol which was individually calculated, on the basis of total body water, to yield a peak BrAC near 80 mg/dl, and the resulting BrAC trajectory was recorded. A few days later, subjects received an intravenous alcohol infusion rate profile, pre‐computed to replicate each individual's oral alcohol BrAC trajectory. In both sessions, we assessed 4 subjective responses to alcohol: SEDATION, SIMULATION, INTOXICATION, and HIGH; at baseline and frequently for 4 hours. We compared the individuals’ baseline‐corrected responses at peak BrAC and at half‐peak BrAC on both the ascending and descending limbs. We also computed and compared Pearson‐product moment correlations of responses by route of administration, the Mellanby measure of acute adaptation to alcohol, and the area under the entire response curve for each subjective response. Results No significant differences in any measure could be attributed to the route of alcohol administration. Eleven of 12 response comparisons were significantly correlated across the routes of alcohol administration, with 9 surviving correction for multiple measures, as did the Mellanby effect and area under the response curve correlations. Conclusion The route of alcohol administration has a minimal effect on subjective responses to alcohol when an individual's BrAC exposure profiles are similar.