Last update April 15, 2024

Losartan Potassium

Likely Compatibility

Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.

It is an angiotensin II receptor antagonist with antihypertensive action It is indicated in the treatment of hypertension and heart failure. Oral administration once daily. 

At the time of the last update, we found no published data on its excretion in breast milk. 

Its high binding to plasma proteins makes its passage into milk unlikely, and its low oral bioavailability makes passage into infant plasma from ingested breast milk difficult (Kearney 2018), except in premature infants and the immediate neonatal period, where there may be greater intestinal permeability. 

Until more data on this drug are known, safer known alternatives are preferable (Rowe 2013), especially in the neonatal period and in case of prematurity.


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.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

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.

José María Paricio, founder of e-lactancia.

Other names

Losartan Potassium in other languages or writings:


Main tradenames from several countries containing Losartan Potassium in its composition:


Variable Value Unit
Oral Bioavail. 33 %
Molecular weight 461 daltons
Protein Binding 99 %
VD 0.5 l/Kg
Tmax 1 - 3 hours
2 - 9 hours


  1. Kearney L, Wright P, Fhadil S, Thomas M. Postpartum Cardiomyopathy and Considerations for Breastfeeding. Card Fail Rev. 2018 Abstract Full text (link to original source) Full text (in our servers)
  2. Rowe H, Baker T, Hale TW. Maternal medication, drug use, and breastfeeding. Pediatr Clin North Am. 2013 Feb;60(1):275-94. Abstract
  3. Merck. Losartan. Drug Summary 2013 Full text (in our servers)
  4. AEMPS. Losartan. Ficha técnica. 2011 Full text (in our servers)
  5. Tamargo j, Caballero R, Gómez R, Núñez L, Vaquero M y Delpón E. Características farmacológicas de los ARA-II. ¿Son todos iguales?. Rev Esp Cardiol Supl. 2006;6:10C-24C. 2006 Full text (in our servers)

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