Elimination kinetics of ethanol and acetaldehyde in healthy men during the calcium carbimide-alcohol flush reaction.

In a crossover design experiment, we investigated the elimination kinetics of ethanol and acetaldehyde during the calcium carbimide (CC)-alcohol flush reaction. Ten healthy men swallowed a tablet of calcium carbimide (50 mg) or placebo and about 2 hours later drank 0.25 g/kg ethanol within 5 min. The pulmonary blood concentrations of ethanol and acetaldehyde were estimated indirectly by analysis of end-expired alveolar air. The onset of facial flushing and associated cardiovascular response coincided with the peak concentrations of ethanol and acetaldehyde in blood. The speed of absorption of alcohol was faster in subjects treated with CC. A smaller volume of distribution of ethanol was evident after pretreatment with CC; 0.636 L/kg compared with 0.675 L/kg after placebo. The rate of elimination of ethanol from blood was about 5% slower in subjects given the CC tablet. The disposition kinetics of acetaldehyde were markedly different when aldehyde dehydrogenase (ALDH) was inhibited. The maximum blood-levels of acetaldehyde ranged from 40-242 microM compared with 1.7-6.5 microM in the placebo control experiments. The elimination half-life of acetaldehyde after CC treatment ranged from 18-31 min. Our results do not support a significant role of acetaldehyde in regulating in-vivo metabolism of ethanol in humans.