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British Journal of Clinical Pharmacology logoLink to British Journal of Clinical Pharmacology
. 1994 Aug;38(2):99–102. doi: 10.1111/j.1365-2125.1994.tb04331.x

A novel index for expressing exposure of the infant to drugs in breast milk.

S Ito 1, G Koren 1
PMCID: PMC1364853  PMID: 7981020

Abstract

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.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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