Cyclosporine and Lactation: When the Mother Is Willing to BreastfeedOsadchy, Alla MD; Koren, Gideon MD, FRCPTherapeutic Drug Monitoring: April 2011 - Volume 33 - Issue 2 - p 147-148 doi: 10.1097/FTD.0b013e318208e3a4 Grand Round Buy Abstract Author InformationAuthors Article MetricsMetrics We describe a woman treated with cyclosporine after renal transplantation who commenced breastfeeding of her newborn infant. The child had no apparent clinical adverse effects to cyclosporine. To confirm the safety of breastfeeding and guide the patient and her clinician, cyclosporine concentrations in maternal blood, breast milk, and infant blood were measured. Maternal cyclosporine concentration (1-hour postdose) was 49 μg/L, and the breast milk cyclosporine concentration (2-hour postdose) was 46 μg/L. Infant cyclosporine blood concentration shortly after breastfeeding was undetectable (<10 μg/L). Analysis revealed that the estimated infant exposure to cyclosporine via breast milk was minimal and provided reassurance to continue breastfeeding in this case. From the Motherisk Program, Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Toronto, Ontario, Canada. Received for publication July 21, 2010; accepted November 26, 2010. Correspondence: Alla Osadchy, MD, Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G1X8 (e-mail: email@example.com). © 2011 Lippincott Williams & Wilkins, Inc.