Nelfinavir and its active metabolite, hydroxy-t-butylamidenelfinavir (M8), are transferred in small quantities to breast milk and do not reach biologically significant concentrations in breast-feeding infants whose mothers are taking nelfinavir.

Antiretroviral drugs cross from maternal plasma to breast milk and from breast milk to the infant in different concentrations. We measured concentrations of nelfinavir and its active metabolite (M8) in maternal plasma and breast milk from women and in dried blood spots collected from their infants at delivery and postnatal weeks 2, 6, 14, and 24 in the Kisumu Breastfeeding Study, Kisumu, Kenya. Nelfinavir-based antiretroviral regimens given to mothers as prevention of mother-to-child HIV transmission (PMTCT) do not expose the breast-feeding infant to biologically significant concentrations of nelfinavir or M8.