Ursodeoxycholic acid markedly promotes the absorption of microemulsion-formulated cyclosporine A: A case report.

What is known and objective Cyclosporine A (CyA) causes intrahepatic biliary stasis via inhibition of bile acid excretion through the bile salt export pump. We report a case of a patient in whom ursodeoxycholic acid (UDCA) markedly promoted the absorption of microemulsion-formulated CyA. Case summary The patient was a 22-year-old Japanese man diagnosed with stage 3 aplastic anaemia. He was treated with CyA, and 2 h post-dose (C2) was increased by UDCA. What is new and conclusion A remarkable interaction was observed between CyA and UDCA. This is a valuable finding for improving the treatment strategies for haematological disorders.