Effects of breast pumping on the pharmacokinetics and pharmacodynamics of ethanol during lactation

This study tested two hypotheses. First, that breast pumping contributes to the previously observed decrease in ethanol bioavailability in lactating women. Second, that the effects of breast pumping are more pronounced when ethanol is consumed after a meal. The within-subject factor was test condition (fed or fasted) and the between-subject factor was experimental group (pumped before, PB; pumped after, PA). Those randomly assigned to the PB group (N = 8) breast pumped 1 h before drinking, whereas those assigned to the PA group (N = 8) breast pumped 0.6 h after drinking. Pumping before drinking significantly decreased blood ethanol concentration (P < 0.05) and ethanol bioavailability (P = 0.05). Pumping after drinking sped up elimination (P = 0.008), attenuated ethanol-induced hypothermia (P = 0.002), and increased feelings of stimulation (P = 0.03). The effects were more pronounced when ethanol was consumed after a meal. Common neural/hormonal responses to food and suckling may contribute additive effects in altering the pharmacokinetics/pharmacodynamics of ethanol, and perhaps of other drugs, during lactation.