Maternal PPI therapy during lactation: pantoprazole levels in human milk and possible neonatal implications

Proton pump inhibitors (PPIs) are widely used for acid-related disorders, but limited data exist regarding their excretion into human breast milk. This study aimed to quantify pantoprazole levels in plasma and breast milk of lactating women and to assess potential infant exposure. Sixteen mothers who had discontinued breastfeeding and were prescribed 40 mg pantoprazole once daily participated. Blood and breast milk samples were collected on days 1 and 7 at 0, 1.5, 3, 4.5, and 6 h post-dose. Pantoprazole was quantified using a validated high-performance liquid chromatography (HPLC) method with omeprazole as the internal standard. Samples were extracted via liquid-liquid extraction, and the method was validated over a linear range of 0.03-1 µg/mL (LOQ 0.03 µg/mL). Pantoprazole was detected in 46% (69/150) of plasma samples and 17.4% (26/149) of breast milk samples. Plasma levels peaked at ~ 4.5 h, whereas breast milk concentrations peaked at 3-4.5 h on day 1 and at 3 h on day 7. The low detectability and consistently lower breast milk concentrations suggest limited transfer into breast milk. Pantoprazole levels in breast milk were consistently lower than plasma and infrequently detectable. CONCLUSION: This study, representing the largest series to date examining pantoprazole excretion during lactation, suggests that infant exposure via breast milk is low. These findings suggest that breastfeeding may be compatible with pantoprazole therapy, although caution is warranted. The data provide supportive evidence for clinical decision-making. WHAT IS KNOWN: • Proton pump inhibitors (PPIs) are widely prescribed during lactation, but robust safety and pharmacokinetic data for pantoprazole transfer into breast milk remain limited. • Current breastfeeding recommendations for PPIs are based largely on expert opinion and isolated case reports with limited milk sampling. WHAT IS NEW: • Peak concentrations occurred 3-4.5 hours post-dose, and milk levels were consistently much lower than plasma levels. • Pantoprazole was detected in few milk samples and at concentrations markedly lower than plasma levels, indicating negligible infant exposure and supporting breastfeeding compatibility during therapy.