Is Ritonavir safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Ritonavir. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
Relevant published information was not found as of the revision date.
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.[ 10 - 12 ] Some case reports and in vitro studies have suggested that protease inhibitors might cause hyperprolactinemia and galactorrhea in some male patients,[ 13 , 14 ] although this has been disputed.[ 15 ] 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. One study measured ritonavir in breastmilk samples from nursing mothers who had been randomized to receive the drug as part of a clinical trial to evaluate maternal-to-child transmission of HIV infection. The dosages, dosage regimens and times of breastmilk sample collection times were not reported. Ritonavir was not detected in any of 60 breastmilk samples.[ 3 ] Nine mothers who were receiving lopinavir 400 mg plus ritonavir 100 mg twice daily as part of a combination antiretroviral regimen provided a total of 23 milk samples at birth, 1 month, 3 months and/or 6 months postpartum. Milk samples were collected at a median of 4.5 hours (range 3.5 to 6 hours) after the previous dose. The median breastmilk ritonavir concentration was 79 mcg/L (range 31 to 193 mcg/L).[ 4 ] Thirty women were studied at 6, 12 or 24 weeks postpartum (10 at each time). Each mother was taking zidovudine 300 mg, lamivudine 150 mg, lopinavir 400 mg, and ritonavir 100 mg twice daily by mouth starting at delivery. On the study day, at a median of 14.9 hours after the previous evening's dose, maternal plasma and breastmilk samples were obtained prior to the morning dose and 2, 4 and 6 hours after the dose. One hundred twelve of the 121 breastmilk samples contained detectable quantities (10 mcg/L or greater) of ritonavir, with a median breastmilk concentration of 79 mcg/L over the 6 hours.[ 5 ] Nine HIV-positive women about to undergo cesarean section received 3 doses of lopinavir 200 mg, ritonavir 150 mg, zidovudine 300 mg, lamivudine 50 mg at 3 hour intervals before the procedure. Breastmilk samples were collected at a mean of 25 hours postpartum. In the 8 women where it was quantified, the average milk concentration of ritonavir was 240 mcg/L (range 98 to 402 mcg/L).[ 6 ] Eight women who were taking nirmatrelvir-ritonavir and had donated milk samples to a breastmilk repository had their milk analyzed for nirmatrelvir. All were taking a ritonavir dose of 100 mg twice daily and re
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.