Limited information indicates that trientine is not detectable in breastmilk, and no adverse effects have been reported among breastfed infants whose mothers were taking the drug. The effect of trientine on breastmilk copper and zinc concentrations in milk is somewhat conflicting,[1-4] but breastfed infants appear to have normal serum copper and zinc plasma levels. Based on available data, it appears that trientine is acceptable to use during breastfeeding.