Effects of menstrual cycle and female sex steroids on ethanol pharmacokinetics

This study investigated the influence of menstrual cycle and female sex ste roid levels on ethanol pharmacokinetics. In a within-subjects design, 24 fe male volunteers each consumed 0.67 g.kg(-1) ethanol during the menstrual an d luteal phases of their menstrual cycle. On each test day, we collected bl ood samples before ethanol administration to determine estradiol (E-2) and progesterone (P) levels and to confirm ovulation, We took 20 or more postdr ink breath ethanol concentration readings and examined pharmacokinetic diff erences between the two phases, using classical pharmacokinetic measures, a s well as Michaelis-Menten measures. Despite highly significant differences in measured E-2 as well as P levels on the 2 test days, and despite exclud ing subjects with anovulatory cycles from the analysis, there were no signi ficant differences between menstrual and luteal phases for any of the pharm acokinetic variables. We found no correlation between E-2 or P levels and a ny of the pharmacokinetic measures. In summary, we found no evidence that t he tested menstrual cycle phases or varying E-2 and progesterone levels sig nificantly influence ethanol pharmacokinetics, Because previous studies abo ut the topic have used few subjects and revealed controversial results, we consider our negative findings based on 24 subjects meaningful.