Is Atazanavir safe while breastfeeding?

Summary of use during breastfeeding

Amounts of atazanavir in milk appear to be low based on limited data. The combination product, which also contains the CYP3A inhibitor cobicistat, has not been studied during breastfeeding, but would be expected to have similar or greater levels of atazanavir in milk. 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]

Effects on the breastfed infant

Fourteen exclusively breastfeeding women with HIV were receiving ritonavir 100 mg and atazanavir 300 mg daily, as part of a multi-drug regimen. Thirteen of fourteen infants received nevirapine-based prophylaxis. No infant experienced a Grade 3 or higher event or serious adverse event. Three infants (21%) experienced Grade 2 adverse events: one with viral rhinitis (16.6 weeks), one with a chest abscess (7.4 weeks), and one with pruritus and papular rash (4.9 weeks). None of the reported events were considered to be related to atazanavir-ritonavir exposure via breastmilk.[4]

Effects on milk supply

Gynecomastia has been reported among men receiving highly active antiretroviral therapy. Gynecomastia is unilateral initially, but progresses to bilateral in about half of cases. No alterations in serum prolactin were noted and spontaneous resolution usually occurred within one year, even with continuation of the regimen.[5-7] Some case reports and in vitro studies have suggested that protease inhibitors might cause hyperprolactinemia and galactorrhea in some male patients,[8,9] although this has been disputed.[10] The relevance of these findings to nursing mothers is not known. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Levels in milk

Maternal Levels. Three women taking atazanavir (dose not stated, but presumably 300 mg daily) as part of their highly active antiretroviral regimen had sampling of breastmilk and plasma on postpartum days 5 and 14 at 0, 2, 5, 8 and 24 hours after a dose. Median breastmilk levels over 24 hours were 212 mcg/L on day 5 and 265 mcg/L on day 14. Median peak breastmilk levels of 419 mcg/L occurred at 5 hours after the dose.[3]

Fourteen breastfeeding women with HIV were receiving ritonavir 100 mg and atazanavir 300 mg daily, as part of a multi-drug regimen. Milk samples were collected at three postpartum visits: 5 to 9 days postpartum, 2 to 12 weeks postpartum, and 16 to 24 weeks postpartum. The median breastmilk atazanavir concentrations were 432 mcg/L (IQR 126, 633 mcg/L) at a median time of 17.2 hours (IQR 14.5, 18.9 hours) between the dose and sample collection. The median atazanavir RID was 1.27% (maximum 6.43%).[4]

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