The effect of administering ethanol as single vs. divided doses on blood alcohol levels in the rat.

The magnitude of peak blood alcohol levels (BALs) and duration of exposure are critical determinants of alcohol's effects. This technical report provides BAL data for different doses (2, 3, 4, 5, or 6 g/kg) administered as single (at 12:00 h) or dual doses (at 07:00 and 12:00 h) of alcohol when administered by intubation at several time points (0.5, 1, 2, 4, 6, and 24 h after the 12:00 h intubation) in male rats. Administration of the highest dose in a single intubation resulted in the highest peak BALs, a later peak in BAL, and a longer latency to return to 0 mg% ethanol in the blood. Other combinations resulted in different profiles. The differences are explained in terms of "first-pass" effects relating to alcohol's elimination via the liver. These findings should be of practical use to researchers using intubation as their method of alcohol administration, especially when the timing and magnitude of peak BAL are critical.