Concentration-response relationships for dihydropyridine compounds with Nav1.8 activity determined using automated patch clamp. Nicardipine (CPI1073) and nilvadipine (CPI1076) were found to be the most potent with IC50 = 0.6 μM, followed by nimodipine (CPI1075, 1.2 μM), benidipine (CPI1074, 4.4 μM) and nifedipine (CPI1077, 16.7 μM).