抄録
Maternal milk volume safely given to the infant was estimated when the mother takes Phenobarbital (PB) or Phenytoin (PHT) or Valproic acid (VPA) or Carbamazepin (CBZ) or Theophylline (TP). To calculate the milk volume given to the infant, it was assumed that these drugs given to the mother and those transferring from maternal milk to the infant are at a steadystate and that the infant takes a constant volume of milk each time, every 6 hours, 4 times a day, and that the infant's body weight is 4 kg. The calculated milk volume by using the pharmacokinetic parameters of the infant and milk-to-plasma drug concentration ratio (M/P ratio) are respectively 65, 547, 589, 968, and 100ml/day when the infant's Cmax a steady state which is less than 5% of maternal serum level is considered to be safe. This result indicates that maternal milk can be given to the infant safely when the mother takes CBZ and must not be given when the mother takes PB or TP and should be given to the infant carefully within the limits of permitted volume when the mother takes PHT or VPA since the infant is evaluated to take 600 to 840ml/day volume of milk.
TP secretion into breast milk was investigated. The measured M/P ratio was larger than the calculated M/P ratio according to pH-partitioing theory. This result suggests that some other factor influences TP secretion into breast milk to increase the M/P ratio.
