Last update June 14, 2023


Very High Risk

Very unsafe. Contraindicated. Use of an alternative or cessation of breastfeeding. Read the Comment.

It is an antineoplastic, tyrosine kinase inhibitor, used in the treatment of certain types of lung cancer.. Oral administration once daily.

Since the last update we have not found published data on its excretion in breastmilk.

Its pharmacokinetic characteristics (very high plasma protein binding, very large volume of distribution and moderately elevated molecular weight) make it very unlikely its excretion into breast milk in significant amounts.

Its long half-life could facilitate excretion in breast milk and due to its high bioavailability, it would have systemic action in the infant.

It has potentially very serious side effects.

It is known from pharmacokinetics that after 3 elimination half-lives (T½) 87.5% of the drug is eliminated from the body; after 4 T½ it is 94%, after 5 T½, 96.9%, after 6 T½, 98.4% and after 7 T½ it is 99%. From 7 T½ the plasma concentrations of the drug in the body are negligible. In general, a period of at least five half-lives can be considered a safe waiting period before breastfeeding again.(Anderson 2016).

Taking the longest T½ published as a reference (48 hours), these 5 T½ would correspond to 10 days. Meanwhile, breast milk must be expressed and discarded regularly. This does not allow breastfeeding during treatment.

See below the information of this related product:

  • Maternal Cancer ( Poorly safe. Evaluate carefully. Use safer alternative or interrupt breastfeeding 3 to 7 T ½ (elimination half-lives). Read the Comment.)


We do not have alternatives for Osimertinib.

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

Osimertinib is also known as

Osimertinib in other languages or writings:


Osimertinib belongs to these groups or families:


Main tradenames from several countries containing Osimertinib in its composition:


Variable Value Unit
Oral Bioavail. 70 %
Molecular weight 500 daltons
Protein Binding 95 %
VD 13.11 l/Kg
pKa 13.64 -
Tmax 6 hours
48 hours


  1. Astra Zeneca. Osimertinib. Drug Summary. 2023 Full text (in our servers)
  2. EMA. Osimertinib. Ficha técnica. 2022 Full text (in our servers)

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