Extended absorption, implications: Rethinking alcohol pharmacokinetics in forensic calculations

Forensic toxicologists routinely perform pharmacokinetic calculations for alcohol, such as retrograde extrapolation calculations that rely on assumptions about when alcohol absorption is complete. However, examination of current practice reveals a uniformity in applying standardised timing assumptions despite well-documented individual variation in alcohol pharmacokinetics. This paper highlights factors that can influence alcohol absorption and cause the absorption of alcohol to extend beyond the conventional 2-hour timeframe since the last drink. Various physiological conditions, including the presence of food, certain medications, medical conditions and other factors, can prolong alcohol absorption beyond 2 hours. Toxicologists performing pharmacokinetic calculations for alcohol should disclose that population averages regarding the absorption of alcohol may not apply to individual cases.