Oseltamivir

Drug Levels and Effects:




Summary of Use during Lactation:


Limited data indicate that oseltamivir and its active metabolite are poorly excreted into breastmilk. Maternal dosages of 150 mg daily produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. Infants over 1 year of age can receive oseltamivir directly in doses much larger than those in breastmilk.


Drug Levels:


Maternal Levels.

A nursing mother who was 9 months postpartum was given oseltamivir 75 mg by mouth twice daily for 5 days. She

Maternal Levels.

A nursing mother who was 9 months postpartum was given oseltamivir 75 mg by mouth twice daily for 5 days. She collected 8 milk samples within 30 minutes of taking an oseltamivir dose and 2 after the last dose. Milk was analyzed for oseltamivir and its carboxylate metabolite. Oseltamivir milk concentrations fluctuated depending on the time of the milk sample, but oseltamivir carboxylate concentrations were generally higher and reached a steady-state between 37 to 39 mcg/L after 3 days of therapy. The authors calculated that at worst, the infant would receive 0.012 mg/kg daily, compared to the dosage for infants over 1 year of 4 mg/kg daily. The dose in milk corresponded to 0.5% of the mother's weight-adjusted dosage.[1]

Seven postpartum women who were bottle feeding their infants donated milk samples at the time of and 0.5, 1, 2, 4, 8, 12, and 24 hours after a single 75 mg oral dose of oseltamivir. Both oseltamivir and its metabolite, oseltamivir carboxylate were measured in milk samples. The average peak milk level of oseltamivir of 26.9 mcg/L occurred at an average of 3.4 hours after the dose and the average peak milk level of oseltamivir carboxylate of 41.9 mcg/L occurred at an average of 18.9 hours after the dose. Using area under the curve (AUC) data reported in the paper and thestandardizedmilk intake of 150 mL/kg daily, a fully breastfed infant would receive daily dosages of about 0.9 mcg/kg of oseltamivir and 3.6 mcg/kg of oseltamivir carboxylate. These values would be doubled with the usual dosage of 75 mg twice daily, but the sum of these entities is far below the dose reportedly used in infants of 1 to 7 mg/kg daily.[2]

Infant Levels.

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


Effects in Breastfed Infants:


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


Possible Effects on Lactation:


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


Alternate Drugs to Consider:


Oseltamivir


References:


1. Wentges-van Holthe N, van Eijkeren M, van der Laan JW. Oseltamivir and breastfeeding. Int J Infect Dis. 2008;12:451. PMID:18243025
2. Greer LG, Leff RD, Rogers VL et al. Pharmacokinetics of oseltamivir in breast milk and maternal plasma. Am J Obstet Gynecol. 2011;204:524.e1-4. PMID:21457910



Substance Identification:




Substance Name:

Oseltamivir

CAS Registry Number:

196618-13-0

Drug Class:


  • Antiinfective Agents

  • Antiviral Agents

  • Neuraminidase Inhibitors


  • Administrative Information:




    LactMed Record Number:


    605


    Last Revision Date:


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