Zoniporide hydrochloride is a potent and selective inhibitor of Na+/H+ exchanger isoform 1 (NHE-1), which is mostly expressed in the heart. Zoniporide inhibits NHE1-dependent Na+ uptake (IC50: 14 nM) and protects from cardiac ischemia-reperfusion injury (EC50 = 0.25 nM).