Quantification of infant exposure to celecoxib through breast milk

To determine the milk-to-plasma (M/P) concentration ratio of celecoxib, and estimate likely infant exposure.

Blood and milk were sampled for 48 h after oral administration of celecoxib 200 mg to six lactating volunteers. The M/P ratio was derived from the area under the concentration-time curves (0-infinity) and the infant 'dose' estimated from celecoxib concentrations in milk.

The median (range) M/P ratio was 0.18 (0.15-0.26). The median (range) infant 'dose' was 0.23% (0.17-0.30%) of the maternal dose, adjusted for weight.

The relative 'dose' of celecoxib to which infants are exposed via milk is very low, suggesting that breastfeeding during routine dosing would pose minimal risk.