Interferon Alfa

Drug Levels and Effects:

Summary of Use during Lactation:

Because of the low levels in milk, poor oral absorption by the infant, it is unlikely that interferon use by a nursing mother presents any serious risk to the breastfed infant. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of endogenous interferon-gamma by an average about 10%.[1]

Drug Levels:

Two mothers taking interferon alfa had milk levels measured. One mother taking 8 million units three times a week had a milk level of 1400 units/L and another taking 8 million units/day had a milk level of 6000 units/L. Both levels were apparently measured immediately postpartum (in colostrum), but the time since the previous dose was not stated.[2]

An intravenous dose of 30 million units of interferon alfa-2B in one woman resulted in a peak milk level of 1551 International Units/L which was a slight increase over two baseline levels prior to the dose which averaged 1072 International Units/L . By 12 hours after the dose, milk interferon levels were lower than baseline.[3]

Effects in Breastfed Infants:

One infant was born to a mother who received 3 million units of interferon alfa subcutaneously 3 times weekly during pregnancy and postpartum for essential thrombocytopenia. Her infant was breastfed for 2 weeks postpartum before bilateral mastitis caused the mother to terminate nursing. The infant reportedly thrived, although specific measures were not mentioned.[4]

Possible Effects on Lactation:

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

Alternate Drugs to Consider:

Dependent on the condition being treated.


1. Ewaschuk JB, Unger S, O'Connor DL et al. Effect of pasteurization on selected immune components of donatedhumanbreast milk. J Perinatol. 2011;31:593-8. PMID:21330996
2. Haggstrom J, Adriansson M, Hybbinette T et al. Two cases of CML treated withalpha-interferon during second and third trimester of pregnancy with analysis of the drug in the new-born immediately postpartum. Eur J Haematol. 1996;57:101-2. Letter. PMID:8698119
3. Kumar AR, Hale TW, Mock RE. Transfer of interferon alfa intohumanbreast milk. J Hum Lact. 2000;16:226-8. PMID:11153157
4. Williams JM, Schlesinger PE, Gray AG. Successful treatment of essential thrombocythaemia and recurrent abortion withalphainterferon. Br J Haematol. 1994;88:647-8. PMID:7819084

Substance Identification:

Substance Name:

Interferon Alfa

CAS Registry Number:


Drug Class:

  • AntiInfective Agents

  • Antiviral Agents

  • Antineoplastic Agents

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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