One impediment to breastfeeding is the lack of information on the use of many drugs during lactation, especially newer ones. The principles of drug passage into breastmilk are well established, but have often not been optimally applied prospectively. Commonly used preclinical rodent models for determining drug excretion into milk are very unreliable because of marked differences in milk composition and transporters compared to those of humans. Measurement of drug concentrations in humans remains the gold standard, but computer modeling is promising. New FDA labeling requirements present an opportunity to apply modeling to preclinical drug development in place of conventional animal testing for drug excretion into breastmilk, which should improve the use of medications in nursing mothers.
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Area under the concentration-time curve
Total body drug clearance
Drug concentration in plasma
Cytochrome P450 2D6
U.S. Food and Drug Administration
Human immunodeficiency virus
Infant to maternal plasma concentration ratio
Milk to plasma concentration ratio
Physiologically based pharmacokinetic
Pregnancy and Lactation Labeling Rule
Quantitative structure-activity relationship
Relative infant dose
World Health Organization
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The author thanks Edmund Capparelli, Pharm. D. for his review of the manuscript and helpful suggestions. The author declares no competing financial interests.
Guest Editor: Sara Eyal
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Anderson, P.O. Drugs in Lactation. Pharm Res 35, 45 (2018). https://doi.org/10.1007/s11095-017-2287-z
- breast feeding
- drug excretion
- human milk