An inhibitor of Kir4.1 (IC50 = 5.2 µM in a thallium flux assay); selective for Kir4.1 over Kir2.3, Kir7.1, and SUR1/Kir6.2 (IC50s = 13.2, 34.2, and 11.4 µM, respectively), as well as Kir1.1, Kir2.1, and Kir2.2 at 30 µM; inhibits Kir4.2, heteromeric GIRK1/GIRK2, and heteromeric GIRK1/GIRK4 (IC50s = 8.1, 2.5, and 3.1 µM, respectively); reduces polymyxin B-induced decreases in cell viability in HK-2 cells and prevents polymyxin B-induced increases in apoptosis in mouse embryonic kidney explant cultures at 5 µM; increases urine volume and urinary sodium and potassium levels in rats at 50 and 100 mg/kg