An Nav1.8 sodium channel blocker (IC50 = 0.19 μM for human Nav1.8); selective for Nav1.8 over Nav1.1, Nav1.2, Nav1.5, and Nav1.7 channels (IC50s = 13, 12.8, 9, and 19 μM, respectively) as well as ERG potassium channels (IC50 = 30 μM); blocks Nav1.8 channels in a VSP-FRET assay using HEK293 cells (IC50 = 2.6 μM); reduces phase 2 flinching in a rat model of formalin-induced persistent pain at 100 mg/kg; increases latency to lift the inflamed paw and latency to paw withdrawal in rat models of carrageenan-induced thermal hyperalgesia and CFA-induced mechanical hyperalgesia, respectively