Plasma and Breast Milk Pharmacokinetics of Tenofovir Disoproxil Fumarate in Nursing Mother with Chronic Hepatitis B-Infant Pairs.

Objective: Tenofovir use is associated with lower risk of mother-to-infant transmission of the virus and discontinuation of the treatment is not safe. However, the safety of the drug during pregnancy and breast-feeding is not clear. In this study, we aimed to determine of tenofovir concentration in plasma of mother-infant pairs along with breast milk in chronic hepatitis B patients during lactation period. Patients and Method: A total of eleven mother-infant pairs were enrolled in the study. All the mothers received tenofovir disoproxil fumarate (TDF) 245 mg/day for at least one month because of chronic hepatitis B infection. Maternal blood, breast milk and infant blood samples were obtained concomitantly. Tenofovir concentrations were determined by liquid chromatography tandem mass spectrometry method. Results: The median concentrations of tenofovir in maternal plasma and breast milk samples were 88.44 (IQR: 62.47-116.17) ng/mL, 6.69 (IQR: 4.88-7.03) ng/mL, respectively. Tenofovir concentrations were undetectable (<4 ng/mL) in all of the infant plasma samples. The ratio of tenofovir concentration in breast milk/maternal plasma was 0.07. Conclusion: Tenofovir disoproxil fumarate passes through the breast milk in a small amount. Infants had no detectable tenofovir level in their plasma. Our study suggests that tenofovir disoproxil fumarate treatment is safe during breastfeeding period in chronic hepatitis B patients.