Fostemsavir and Breastfeeding

Summary of use during lactation

No information is available on the use of fostemsavir during breastfeeding. Because the drug and its active metabolite temsavir are over 80% protein bound, the amounts in milk are likely to be low. Achieving and maintaining viral suppression with antiretroviral therapy decreases breastfeeding transmission risk to less than 1%, but not zero. Individuals with HIV who are on antiretroviral therapy with a sustained undetectable viral load and who choose to breastfeed should be supported in this decision. If a viral load is not suppressed, banked pasteurized donor milk or formula is recommended.[1,2]

Drug levels in milk and infant serum

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

Effects on lactation and breastmilk

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

References

1. World Health Organization. Consolidated guidelines on HIV prevention, testing, treatment, service delivery and monitoring: Recommendations for a public health approach. 2021. https://www.who.int/publications/i/item/9789240031593 PubMed
2. Department of Health and Human Services. Recommendations for the use of antiretroviral drugs during pregnancy and interventions to reduce perinatal HIV transmission in the United States. 2024. https://clinicalinfo.hiv.gov/sites/default/files/guidelines/documents/perinatal-hiv/guidelines-perinatal.pdf