Reversible cholinesterase inhibitor used for treatment of Myasthenia gravis and as an analgesic adjuvant in epidural anesthesia (see specific info). It is not excreted into breastmilk (Fraser 1963, Wilson 1981).A breastfed neonate whose mother were treated with neostigmine suffered of abdominal colicky pain after a feeding, but the neostigmine plasma levels were undetectable (Fraser 1963). Because of a low oral bioavailability it seems even more unlikely the pass to the infant’s plasma through ingested breastmilk, except in preterm infants and immediate neonatal period, when there may be an increased intestinal permeability. On long-term treatments, because there is less published experience than with other drugs of the same group, a known safer alternative would be preferred during the neonatal period and/or in case of prematurity.