A novel index for expressing exposure of the infant to drugs in breast milk.
1. We present a novel index for expressing the exposure of the infant to drugs in breast milk, which unifies two independent factors: a pharmacokinetic parameter, drug clearance, and a physiochemical parameter, i.e. milk-to-maternal plasma drug concentration ratio (M/P ratio). 2. During breast-feeding by a woman receiving therapeutic doses of a drug at steady state this index is given by: Exposure index = A x (M/P ratio)/CLI where A is a coefficient (10 ml kg-1 min-1) and CLI is drug clearance in the infant (ml kg-1 min-1). 3. This equation indicates a hyperbolic relationship between drug clearance and the exposure level of the breast-fed infant at a given M/P ratio of drug, emphasizing the importance of drug clearance as a determinant of infant exposure.
Ito
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S
Department of Pediatrics, Hospital for Sick Children, Toronto, Canada.
Koren
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G
D001942:Breast Feeding; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008657:Metabolic Clearance Rate; D008895:Milk, Human / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D010599:Pharmacokinetics; D012044:Regression Analysis; D018570:Risk Assessment
D004364:Pharmaceutical Preparations