I am a nursing student from the University of North Dakota. I have a question regarding the use of oral antidiabetic agents while breastfeeding. It is noted that blood glucose levels of breastfeeding mothers may often be lower then they usually are. This is because the serum glucose is transferred to the breast, converted to lactose, and excreted in the breast milk. Because of this fact, some lactating mothers with diabetes will often have a decreased need for oral hypoglycemics or insulin (Olds, London, & Ladewig, 1996, p. 445). However, if a breastfeeding mother could benefit from the use of oral antidiabetics, the risks versus the benefits would have to be carefully weighed. There are many factors that determine how easily a drug will pass from maternal circulation into the breast milk. Fat-soluble drugs easily gain access to human milk. In contrast, highly protein-bound medications are restricted from leaving the maternal plasma. Other factors include maternal weight, pKa (helps determine the ionization of a drug at certain plasma and milk pHs), and the difference in pH between maternal plasma and the breast milk (Sagraves, 1997, p. 232). Julie Everett (1997) noted that there is still a great deal of controversy on whether or not oral antidiabetic agents can be used on the breastfeeding woman. There is limited information on the extent of distribution of these agents into the breast milk. The sulfonylureas are the only class of antidiabetic agents in which there is published data about their effect on breast milk and the infant. Tolbutamide (first-generation sulfonylurea) is considered to be the only safe sulfonylurea while breastfeeding. The infant should be monitored for hypoglycemia and any other unexpected signs when using any type of sulfonyurea. In theory, it is thought that acarbose (Alph-glucosidase inhibitor) is most likely the safest of the newer agents to use in a breastfeeding woman. Acarbose has a large molecular size and limited systemic absorption. Metformin (Biguanide) is another agent that could be adequate because it does not cause hypoglycemia. However, this agent could increase the risk of the infant developing lactic acidosis. There is not much information on the newest antidiabetic agent, troglitazone (Thiazolidinedione). This agent could possibly be used safely in the breastfeeding woman (Everett, 1997, p. 319-321). Taking all this information into consideration, I am interested to know what antidiabetics, if any, are commonly used in breastfeeding women. Additionally, when these agents are used, are there any infant reactions that are commonly observed? I would appreciate your thoughts on this issue and any other comments you may have. Thank you, Jessica Hafey, College of Nursing (University of North Dakota). Everett, J. (1997). Use of Oral Antidiabetic Agents During Breastfeeding. Journal of Human Lactation, 13(4), p. 319-321. Olds, S. B., London, M. L., & Ladewig, P. W. (1996). Maternal Newborn Nursing. Addison-Wesley Nursing, A Division of The Benjamin/Cummings Publishing Company, Inc: Menlo Park, CA. Sagraves, R. (1997). Pediatric Pharmacology, Drugs in Breast Milk; a Scientific Explanation. Journal of Pediatric Health Care, 11(5), p. 230-237.