Description: IC50 Value: 0.43 ± 0.15 μM (Na+/K+-ATPase activity from dog kidney) [1] Istaroxime is a positive inotropic agent that mediates its action through inhibition of sodium/potassium adenosine triphosphatase (Na+/K+ ATPase). Istaroxime is an investigational drug originally patented and developed by the italian pharmaceutical company Sigma-Tau. Istaroxime is now under development for treatment of acute decompensated heart failure by CVie Therapeutics. in vitro: PST2744 inhibited the Na+/K+-ATPase activity from dog kidney with an IC50 value of 0.43 ± 0.15 μM [1]. The transient inward current (I(TI)) induced by a Ca(2+) transient in the presence of complete Na(+)/K(+) pump blockade was inhibited (-43%) by PST2744 but not by digoxin [2]. in vivo: Intravenous infusion of 0.2 mg/kg/min PST2744 in anesthetized guinea pigs exerted an immediate and long-lasting inotropic effect (ED(80) of 1.89 +/- 0.37 mg/kg) without causing lethal |