Transfer of Montelukast into Human Milk During Lactation.

AIM: The aim of this study was to determine levels of montelukast in human milk and to develop a simple, sensitive analytical method using mass spectrometry.

METHODS: Milk samples were collected from seven breastfeeding mothers, age 26-35 years, at 0, 1, 2, 4, 8, and 12 hours after oral ingestion of 10 mg montelukast. The samples were analyzed using a new Liquid Chromatography-Tandem Mass Spectrometry method. Area under the milk concentration time curve from zero to the time of the last sample (12 hours) was estimated by the linear trapezoidal rule.

RESULTS: Average montelukast levels (Cavg ) in milk were 5.3 ng/mL, and the relative infant dose was 0.68% of the maternal dose. The maximum concentration (Cmax ) observed at 4 hours (Tmax) was 9.7 ng/mL.

CONCLUSION: The exposure to the infant seems to be very low, far below therapeutic ranges in an infant. Our data suggest that montelukast is probably safe to use in a breastfeeding mother.