Effect of the menstrual cycle in ethanol pharmacokinetics.

Differences in ethanol pharmacokinetics within the menstrual cycle have previously been reported and attributed to variations in body composition, hormonal influences and gastric emptying. To establish the role of the menstrual cycle in ethanol pharmacokinetics associated with changes in body composition, ethanol blood concentrations were measured in nine healthy women during the midfollicular (P1, days 8-10) and midluteal (P2, days 22-24) phases of the menstrual cycle after a postprandial oral ethanol dose (0.3 g kg(-1)). Total body water was assessed by dual-energy x-ray densitometry (DEXA) on both occasions. Median total body water did not vary during either phase of the menstrual cycle (P1 = 54.54%, P2 = 54.66%; P = 0.9296). Median area under the ethanol concentration-time curve (AUC) was lower during P1 (215.33 mg.h dl(-1)) than during P2 (231.33 mg.h dl(-1))(P = 0.8253). No significant differences were found on ethanol pharmacokinetics in either phase of the menstrual cycle.