Breast milk concentration of hydroxychloroquine in Chinese lactating women with connective tissue diseases

Considering the very limited while varying information about the excretion of hydroxychloroquine (HCQ) into human milk, we sought to determine the breast milk concentrations of HCQ in Chinese lactating patients with connective tissue diseases to assess the safety of HCQ in infants of this population.

Breastfeeding women who had been on HCQ for at least 1 year were recruited. Milk samples were collected at five time points over 12 h. Breast milk HCQ levels were measured by a validated high-performance liquid chromatography (HPLC) assay. According to the general daily milk consumption of 0.15 L/kg for an infant, the dose of HCQ received by the infants via breastfeeding was calculated.

Thirty-three patients completed the study who received HCQ treatment with the following regimens: 0.1 g bid (n = 3), 0.2 g qd (n = 8), 0.2 g bid (n = 21), and 0.2 g qod (n = 1). The mean breast milk HCQ levels (μg/mL) over the 12-h sampling period for each dosage regimen group were 0.4, 0.7, 1.4, and 0.4, respectively. The dose of HCQ (mg) received by the infants via breastfeeding would be 0.4, 0.4, 0.9, and 0.2, which were 0.26%, 0.26%, 0.29%, and 0.26% of the daily maternal doses, respectively. The infant's weight-adjusted relative dose (mg/kg) was 0.1, 0.1, 0.2, and 0.1, respectively, equivalent to 1.9%, 3.0%, 3.0%, and 3.2% of the maternal dose per kilogram body weight, respectively.

Our study found that HCQ has very low concentrations in breast milk. It is probably safe for the patients to give breastfeeding during HCQ therapy period.