Last update May 11, 2019
Very Low Risk
An antineoplastic, antimetabolite and immunosuppressant. It interferes with the synthesis of nucleic acid by inhibiting the metabolism of purines, with actions similar to mercaptopurine.
Its active metabolite, 6-Thioguanine (6-TGN) or thioguanylic acid, is a metabolite of mercaptopurine, which in turn is metabolized by azathioprine (Jorquera 2012, Gearry 2005).
It is administered orally every 24 hours in the treatment of leukemia.
Very low or undetectable levels of in 6-TGN have been found in breastmilk (Pavlidis 2014, Kane 2004), and in plasma of infants breastfed by mothers who were taking azathioprine (Zelinkova 2009, Bernard 2007, Gardiner 2006).
Experts and scientific associations consider the use of mercaptopurine or azathioprine (which are metabolized in the same active form, 6-Thioguanine) as low risk during breastfeeding (Noviani 2016, Nguyen 2016, Mottet 2016, van der Woude 2015 and 2010, Huang 2014, Nielsen 2014, Yarur 2013, Meij 2013, Habal 2012, Ye 2012, Selinger 2012, Van Assche 2010, Gisbert 2010, Raj 2010, Christensen 2008, Mottet 2007).
Given the strong evidence that exists regarding the benefits of breastfeeding for the development of babies and the health of mothers, it is advisable to evaluate the risk-benefit of any maternal treatment, including chemotherapy, individually advising each mother who wishes to continue with breastfeeding (Koren 2013).
We do not have alternatives for Thioguanine since it is relatively safe.
Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.
Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.
Thank you for helping to protect and promote breastfeeding.