Minimal Transfer of Atorvastatin and Its Metabolites in Human Milk: A Case Series

Statins are historically contraindicated during breastfeeding due to theoretical concerns of disruptions in infant development from drug exposure and nutritional changes in milk. Breastfeeding mothers requiring statins often discontinue statins or postpone treatment until breastfeeding cessation, contributing to delays in treatment up to 14 years. This study aims to determine the transfer of atorvastatin and its active metabolites into human milk and evaluate the infant's risk of drug exposure. Milk samples and health information were released from the InfantRisk Human Milk Biorepository for three women taking 20 mg, 40 mg, and 80 mg of atorvastatin daily at steady state conditions. The concentration of atorvastatin (AT) and its active metabolites, ortho-hydroxy AT (2OH AT) and para-hydroxy AT (4OH AT), was quantified in timed milk samples using liquid chromatography-mass spectrometry. The highest absolute infant dose of AT was 0.00027 mg/kg/day, and the highest weight-adjusted relative infant dose of the combined analytes was 0.09%, far below established thresholds for infant safety. Milk cholesterol levels were within previously established norms in the range of 10 mg/dL. The mothers reported no adverse outcomes in the two exposed infants. The transfer of atorvastatin and its metabolites was exceedingly low. While the impact on milk composition in states of hyperlipidemia (whether treated or untreated) is not well understood, it is unlikely that the drug in the milk would be present in clinically significant levels to adversely affect a breastfed infant.