It is an active metabolite of Amitriptyline. Excreted into breast milk in a clinically non-significant amount (Wisner 1997,Matheson 1988, Brixen1982) with no problems observed in breastfed infants from treated mothers (Wisner 2002, 1997 y 1991,Brixen1982). Levels found in the plasma of those infants were very low or undetectable Wisner 2006 y 1991). It is considered one of the safest antidepressants during lactation (Gentile 2014, Nielsen 2012, Hübner 2012, Pringsheim 2012, Davanzo 2011, Lanza 2009, ABM 2008, Weissman 2004).