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

Abstract

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 (IV) alcohol administration techniques, and any differences attributable to the route employed should be understood. Our objective was 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 IV administration.Methods: We conducted a 2-session, within-subject study in 44 young adult, healthy, nondependent 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 IV alcohol infusion rate profile, precomputed 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.Conclusions: The route of alcohol administration has a minimal effect on subjective responses to alcohol when an individual's BrAC exposure profiles are similar.

Relationship between level of response to alcohol and acute tolerance

“…Similar to the data on sleepiness, while low LR subjects tended to demonstrate lower body sway data than high LR subjects, our data did not reveal evidence of acute tolerance for standing steadiness for either LR group. Finally, also consistent with the bulk of the literature (Morzorati et al, 2002; Plawecki et al, 2019), we did not find sex differences or level of response by sex interaction effects (Eng et al, 2005) in the development of acute tolerance or sensitization to alcohol's effects.…”

“…Notably, the SHAS‐7 score correlates highly with the complete 13‐item measure that the Schuckit laboratory has used widely in their research and it uses the same visual analog marking scales to measure an individual's subjective responses to alcohol (Eng et al, 2005; Schuckit et al, 2000). To compare our results more directly with reports from other human laboratories that measure subjective responses to alcohol and that use the Biphasic Alcohol Effects Scale (BAES) (Martin & Moss, 1993; Plawecki et al, 2019), we also analyzed the feeling Sleepy subscale of the SHAS which corresponds best with the Sedation subscale of the BAES. BrACs were also obtained every 30 min.…”

“…The following paradigm was used to compare low and high LR participants on their patterns of within‐session acute tolerance. Using the methods of Plawecki et al, (2019) (Plawecki et al, 2019), the half‐peaks on the ascending and descending BrAC arms, as well as the peak of the individual's BrAC curve, were calculated. Specifically, we used the Spline function in MATLAB ® to determine the latencies corresponding to a session's peak BrAC and to the same half‐peak BrAC on the ascending and descending arms of the BrAC curve.…”

“…Our Hypothesis 1 is that low LR individuals, who have been shown to demonstrate less intense subjective feelings and body sway during the alcohol challenge, will also demonstrate greater levels of acute tolerance (the Mellanby effect) than their sex‐ and age‐matched high LR counterparts. In addition, Hypothesis 2 predicts that the relationship of LR to acute tolerance will be similar across the sexes (Morzorati et al, 2002; Plawecki et al, 2019).…”

To Infuse or Ingest in Human Laboratory Alcohol Research

“…In this study, BrAC curves for participants were nearly identical for ingestion and infusion routes of alcohol administration, and likewise, their subjective responses to alcohol were also nearly identical regardless of the route of administration. This finding suggests a negligible impact of the route of alcohol administration on the experience of intoxication (Plawecki et al, 2019).…”