Last update July 16, 2022

Vincristine sulfate

High Risk

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

Vinca alkaloid, used in the treatment of several types of cancer. It is administered intravenously weekly.

Vincristine was not detected in any of the milk samples from a treated mother. (Codacci 2019)

In spite of a pharmacokinetic data (large molecular weight, high plasma protein binding and large volume of distribution) that would make it unlikely the passage to milk of significant amounts along with a low bioavailability that would hinder the passage to infant plasma, most experts advise against the use of anti-neoplastic drugs during lactation due to a potential harmful effect on the infant (Anderson 2016, Koren 2013, Pistilli 2013, Pentheroudakis 2010) until safety data with relation to breastfeeding are provided.

It is known from pharmacokinetics that after 3 elimination half-lives (T½), 87.5% of the drug is eliminated from the organism; after 4 T½ it is 94%, after 5 T½, 96.9%, after 6 T½, 98.4% and after 7 T½, 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 published T½ of all the active metabolites (155 hours) as a reference, these 5 T½ would correspond to 32 days.

Due to major side effects, it would be advisable to wait 7 T½, which would correspond to 45 days. Meanwhile, express and discard milk from the breast regularly to maintain production.

The pattern of administration and the long elimination half-life make it very difficult to continue breastfeeding during treatment.

When it is possible to do so, milk detections of each patient to determine the total elimination of the drug would be the best indicator to resume breastfeeding between two cycles of chemotherapy.

Chemotherapy does not affect milk production during or after treatment.

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

If the mother wishes, production of milk can be maintained by regularly expressing breastmilk, being able to resume breastfeeding in the periods in which no significant traces of the drug remain in the milk (Anderson 2016) or at the end of the treatment. (Pistilli 2013).

A mother with non-Hodgkin's lymphoma treated with 4 cycles of 21 days of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone expressed and discarded milk the first 10 days of each cycle (3 T½ vincristine) and breastfed the next 10 days before of the next treatment, without problems for the infant. (Hersey 2020)

Some chemotherapeutic agents with an antibiotic effect can alter the composition of the microbiota (bacterial set or bacterial flora) of the milk and the concentration of some of its components (Urbaniak 2014). This possibly occurs temporarily with subsequent recovery, although no harmful effects are assumed or have been reported in breastfed infants.

Women undergoing chemotherapy during pregnancy have lower rates of breastfeeding because they experience difficulties in breastfeeding (Stopenski 2017), needing more support to achieve it.

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 Vincristine sulfate.

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

Vincristine sulfate is also known as

Vincristine sulfate in other languages or writings:


Vincristine sulfate belongs to this group or family:


Main tradenames from several countries containing Vincristine sulfate in its composition:


Variable Value Unit
Oral Bioavail. 0 %
Molecular weight 923 daltons
Protein Binding 99.9 %
VD 8.4 - 10.8 l/Kg
pKa 10.85 -
85 ( 19 – 155) hours


  1. Hersey AE, Giglio P, Kurt H, Tarabulsi G, Chen KK. Diffuse Large B-Cell Lymphoma During Third-Trimester Pregnancy and Lactation. Obstet Gynecol. 2020 Feb;135(2):383-386. Abstract
  2. Codacci-Pisanelli G, Honeywell RJ, Asselin N, Bellettini G, Peters GJ, Giovannetti E, Peccatori FA. Breastfeeding during R-CHOP chemotherapy: please abstain! Eur J Cancer. 2019 Sep;119:107-111. Abstract
  3. Stopenski S, Aslam A, Zhang X, Cardonick E. After Chemotherapy Treatment for Maternal Cancer During Pregnancy, Is Breastfeeding Possible? Breastfeed Med. 2017 Mar;12:91-97. Abstract
  4. Anderson PO. Cancer Chemotherapy. Breastfeed Med. 2016 May;11:164-5. Abstract Full text (link to original source) Full text (in our servers)
  5. Urbaniak C, McMillan A, Angelini M, Gloor GB, Sumarah M, Burton JP, Reid G. Effect of chemotherapy on the microbiota and metabolome of human milk, a case report. Microbiome. 2014 Jul 11;2:24. Abstract Full text (link to original source) Full text (in our servers)
  6. 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
  7. 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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