Drug-alcohol flush reaction and breath acetaldehyde concentration: no interference with an infrared breath alcohol analyzer.

Human volunteers were given a small dose of ethanol (0.25 g/kg body weight) after pretreatment with either calcium carbimide (50 mg) or a placebo according to a crossover design. Calcium carbimide, an inhibitor of aldehyde dehydrogenase, caused intense facial flushing and a pronounced rise in the concentration of acetaldehyde in breath. At 15-min intervals throughout the experiment, breath-ethanol concentrations were determined both by gas chromatography (GC) (specific method) and by infrared (IR) spectrometry with an Intoxilyzer model 4011 breath-alcohol analyzer. The results with these two independent methods of analysis were compared in experiments with and without calcium carbimide pretreatment. The regression equations relating breath-ethanol determinations by GC and IR methods in the two test situations were not significantly different. The elevated breath concentrations of acetaldehyde associated with a drug-alcohol flush reaction do not invalidate the use of infrared breath-alcohol devices for evidential purposes.