Doxazosin treatment of phaeochromocytoma during pregnancy: placental transfer and disposition in breast milk.

Information on transfer of drugs and metabolites into placental blood and breast milk is based on modelling, animal experiments and clinical observations due to lack of experimental evidence in humans. We describe the use of doxazosin in a pregnant woman with a phaeochromocytoma. Treatment of a phaeochromocytoma in pregnancy consists of α‐adrenergic receptor blockade followed by surgical excision either during pregnancy or directly after delivery. We measured doxazosin concentrations before and after delivery in maternal and umbilical cord blood sampled from the umbilical vein and breast milk using a validated toxicology liquid chromatography‐mass spectrometry method. The patient approved these additional tests and publication of her case.