Is Natalizumab safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Natalizumab. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
In a multi-center study of women with inflammatory bowel disease in pregnancy (the PIANO registry), 8 women received natalizumab while breastfeeding their infants. Among those who received natalizumab or another biologic agent while breastfeeding, infant growth, development or infection rate was no different from infants whose mothers received no treatment. An additional 68 women received a biologic agent plus a thiopurine. Infant outcomes were similar in this group.[ 2 ] A retrospective cohort study from the German Multiple Sclerosis and Pregnancy Registry database identified 17 mothers who received natalizumab during breastfeeding. The first natalizumab infusion was administered after a median of 14 days (range 1 124 days) postpartum. Thirteen of the infants had also been exposed to natalizumab during the third trimester of pregnancy. More infants with third-trimester natalizumab exposure had a low birthweight and were hospitalized than unexposed children. Infants were followed up for 1 year. Among the infants exposed only during breastfeeding, the mothers of 2 received the drug every 4 weeks and 2 received it every 6 weeks postpartum. They were breastfed for between 0.6 and 9.2 months. One of the 4 infants was a preterm infant who developed a respiratory syncytial virus infection, and the others had no infections. Two of the infants had normal blood counts postpartum and the two others were not tested.[ 4 ] One hundred eighty-three patients with multiple sclerosis or a related condition who received an anti-inflammatory monoclonal antibody were compared to 183 control patients. No differences were found in the annual rates of hospitalization, annual antibiotic use, or development of their breastfed (extent not stated) infants. Of the 183 patients, 125 received natalizumab.[ 13 ] Ten women with multiple sclerosis received natalizumab during pregnancy through the second trimester and then postpartum. They breastfed (extent not stated) their infants starting after t
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. A woman was started on natalizumab 300 mg intravenously while nursing her 11.5-month-old infant. Multiple milk levels were obtained almost daily over the 50 days after she received a dose on day 1 and another on day 29. Natalizumab was undetectable ( 250 mcg/L) in breastmilk until day 14 when a concentration of 333 mcg/L was measured. A peak level of 1.01 mg/L was detected on day 20. On day 29, the natalizumab milk level was 491 mcg/L when the second dose was given. Milk levels increased to a maximum of 2.83 mg/L on day 50 when breastmilk collection ceased.[ 8 ] Natalizumab was detected in the breastmilk in one of two mothers of newborn infants at a concentration of 1.89 mg/L just prior to a dose. The previous maternal dose had been given during pregnancy, but the maternal dose and time since the previous dose were not reported in the abstract. The other mother had no detectable natalizumab in breastmilk.[ 9 ] Four women who were receiving natalizumab for multiple sclerosis donated breastmilk samples at various times after infusion of 300 mg of the drug up to 5.5 months postpartum. Concentrations of free natalizumab in breastmilk ranged from 2 to 412 mcg/L. One mother had no detectable natalizumab at any time and another had only trivial amounts at 6 time points. Variability in milk levels was considerable but inversely correlated with the time since the infusion. Regression indicated that on average, natalizumab was cleared from milk at about 35 days after a dose, although it was detectable at very low levels beyond this time in 2 samples.[ 10 ] In a multi-center study of women with inflammatory bowel disease in pregnancy (the PIANO registry), 2 women receiving natalizumab provided milk samples at 1, 12, 24, and 48 hours after drug administration. One woman had natalizumab in breastmilk at 12 hours and 24 hours in concentrations of 0.26 and 0.46 mg/L, respectively.[ 2 ] Three mothers provided milk samples at different time points during natalizumab
Alternatives LactMed lists
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.