Last update Nov. 6, 2022

Lapatinib Tosilate / Ditosylate

High Risk

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

It is a dual tyrosine kinase inhibitor directed against two human epidermal growth factor receptors. It is used in the treatment of some types of breast cancer, associated with capecitabine or with an aromatase inhibitor. 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 elevated molecular weight) make it very unlikely its excretion into breast milk in significant amounts.

Although oral bioavailability is low, it is greatly increased when administered with food, so it could have a systemic action in the infant.

The most common side effects of the drug are gastrointestinal disorders (diarrhoea), dermatological reactions and fatigue.

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 (24 hours), these 5 T½ would correspond to 120 hours (5 days). Meanwhile, express and discard milk from the breast regularly. This does not allow breastfeeding during treatment.

Abrupt weaning can be psychologically traumatic for both the mother and the infant. (Pistilli 2013). 

If used during lactation, it is advisable to monitor growth and appetite and the possible appearance of diarrhea in the infant, as well as monitor liver function periodically.

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)

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 Lapatinib Tosilate / Ditosylate.

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

Lapatinib Tosilate / Ditosylate in other languages or writings:


Lapatinib Tosilate / Ditosylate belongs to these groups or families:


Main tradenames from several countries containing Lapatinib Tosilate / Ditosylate in its composition:


Variable Value Unit
Oral Bioavail. baja / poor %
Molecular weight 944 daltons
Protein Binding > 99 %
VD 31 l/Kg
pKa 16.44 -
Tmax 4 hours
14 - 24 hours


  1. Novartis. Lapatinib. Drug Summary. 2022 Full text (in our servers)
  2. EMA. Lapatinib. Ficha técnica. 2019 Full text (in our servers)
  3. Anderson PO. Cancer Chemotherapy. Breastfeed Med. 2016 May;11:164-5. Abstract Full text (link to original source) Full text (in our servers)
  4. Pistilli B, Bellettini G, Giovannetti E, Codacci-Pisanelli G, Azim HA Jr, Benedetti G, Sarno MA, Peccatori FA. Chemotherapy, targeted agents, antiemetics and growth-factors in human milk: how should we counsel cancer patients about breastfeeding? Cancer Treat Rev. 2013 May;39(3):207-11. Abstract
  5. Koren G, Carey N, Gagnon R, Maxwell C, Nulman I, Senikas V; Society of Obstetricians and Gynaecologists of Canada. Cancer chemotherapy and pregnancy. J Obstet Gynaecol Can. 2013 Mar;35(3):263-278. Abstract Full text (link to original source) Full text (in our servers)

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