Immunoglobulin A nephropathy is a common autoimmune nephropathy. A growing body of research suggests that immunoglobulin A nephropathy may be associated with dysfunction of the mucosal immune system. Immunoglobulin A nephropathy is characterized by thylakoid deposition of galactose-deficient IgA1 immune complexes, which are thought to originate from mucosal B-cells, which are abundantly present in the distal ileum, which is rich in Pyle's collecting lymph nodes. A novel targeted release formulation of budesonide has been shown to deliver the drug to the distal ileum with the aim of minimizing adverse events in patients with immunoglobulin A nephropathy. This article reviews the mechanism of action, dosage form characteristics, clinical studies, drug interactions and adverse events, and limitations of budesonide extended-release capsules.