Drug Levels and Effects:

Summary of Use during Lactation:

Granulocyte colony-stimulatingfactor(G-CSF) is a normal component of breastmilk. However, the excretion of exogenous filgrastim in breastmilk or its effects on breastfed infants have not been studied. Limited data indicate that the closely relatedrecombinantG-CSF product, lenograstim, is poorly excreted into breastmilk. Because filgrastim has been safely given orally to neonates and is not orally absorbed by neonates, any filgrastim that is excreted into milk is unlikely to adversely affect the breastfed infant.

Drug Levels:

Granulocyte colony-stimulatingfactor(G-CSF) is a normal component of breastmilk. In the United States, the biosynthetic form that is available for exogenous administration is filgrastim. Other biosynthetic forms of G-CSF are available in other countries. Lenograstim is a glycosylatedrecombinantG-CSF whereas filgrastim is not glycosylated.

Maternal Levels.

A nursing mother who was 4 months postpartum was given therecombinantG-CSF product lenograstim in order to donate peripheral blood stem cells. She was given lenograstim subcutaneously in doses of 300 mcg on day 1,600 mcg daily on days 2 to 4 and 300 mcg daily on days 5 and 6 of therapy. G-CSF concentration in milk was less than 5 ng/L before therapy. G-CSF milk levels increased during therapy with levels of about 58 ng/L on day 4, 78 ng/L on day 5 and 85.7 ng/L on day 6. Sampling times were not stated.[1] The maximum amount in milk represents an infant dosage of about 0.013 mcg/kg which is 13% of an infant subcutaneous dose of exogenous G-CSF and 0.13% of the maternal weight-adjusted dosage.

A woman received subcutaneous injections of filgrastim in the following doses: 600 mcg on day 1,300 mcg twice daily on days 2 to 5, and 300 mcg once on day 6 prior to harvesting white cells for donation. She was nursing her 25-day-old infant and milk G-CSF levels were measured once daily just before the first dose of the day. G-CSF was first detectable (>10 ng/L) in whole milk 12 hours after the start of the regimen, had a peak milk concentration of 188 ng/L at 22 hours after the start of the regimen, and then after 43 hours, slowly declined until G-CSF was undetectable (<10 ng/L) in breastmilk 70 hours after the last dose.[2]

Infant Levels.

Published information on absorption of filgrastim from breastmilk was not found as of the revision date. However, a study in which an oral dose of 100 mcg/kg of filgrastim (10 times the subcutaneous dose) was given to preterm infants found that filgrastim was not absorbed.[3]

Effects in Breastfed Infants:

Published information on the effects of filgrastim in breastmilk was not found as of the revision date. However, oral filgrastim 20 mcg daily for 5 days has been given to preterm infants with stage I necrotizing enterocolitis (NEC). Filgrastim appeared to halt progression to more severe stages of NEC in this small study.[4]

Possible Effects on Lactation:

Relevant published information was not found as of the revision date.


1. Shibata H, Yamane T, Aoyama Y et al. Excretion of granulocyte colony-stimulatingfactorinto human breast milk. Acta Haematol. 2003;110:200-1. PMID:14663166
2. Kaida K, Ikegame K, Fujioka T et al. Kinetics of granulocyte colony-stimulatingfactorin the human milk of a nursing donor receiving treatment for mobilization of the peripheral blood stem cells. Acta Haematol. 2007;118:176-7. PMID:17914246
3. Calhoun DA, Maheshwari A, Christensen RD.Recombinantgranulocyte colony-stimulatingfactoradministered enterally to neonates is not absorbed. Pediatrics. 2003;112:421-3. PMID:12897302
4. Canpolat FE, Yurdakok M, Korkmaz A et al. Enteral granulocyte colony-stimulatingfactorfor the treatment of mild (stage I) necrotizing enterocolitis: a placebo-controlled pilot study. J Pediatr Surg. 2006;41:1134-8. PMID:16769348

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Colony-Stimulating
  • Factors
  • Hematopoietic Cell Growth
  • Factors

    Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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