An inhibitor of heteromeric Kir4.1/5.1 channels (IC50 = 0.24 µM); selective for Kir4.1/5.1 channels over a variety of homomeric Kir channels, including Kir4.1 (IC50 = >10 µM), as well as heteromeric Kir3.1/3.2, Kir3.1/3.4, Kir6.2/SUR1, and Kir6.1/SUR2b channels at 30 µM but does inhibit the voltage-gated potassium channel Kv1.1 (IC50 = 6.4 µM); does not inhibit diuresis in mice at 30 and 100 mg/kg due to low oral bioavailability and high hepatic clearance