Istaroxime hydrochloride(PST2744) is a novel inhibitor of Na+/K+-ATPase with IC50 value of 0.43±0.15μM [1].
In vitro studies show that Istaroxime can inhibit the activity of Na+/K+-ATPase from dog kidney without significant interaction with other several receptors. It demonstrates the selectivity of Istaroxime. Ex vivo studies show the inotropic effect can be achieved up to 60% for Istaroxime. Istaroxime can also increase the force of contraction of guinea pig paced left atria in the range 0.3 to 30μM. In vivo assays prove Istaroxime is consistently safer than digoxin [1].
Istaroxime is a steroidal drug unrelated to cardiac glycosides that improves cellular calcium cycling. The inhibition of Na+/K+-ATPase induces cytosolic calcium accumulation during systole (inotropism). Clinical studies has been done with istaroxime in phase II. Istaroxime could be a promising alternative for patients with acute heart failure syndrome for whom the therapeutic options are currently limited [2].
References:
[1] R. Micheletti, G. G. Mattera, M. Rocchetti, A. Schiavone, M. F. Loi, A. Zaza, R. J. P. Gagnol, S. De Munari, P. Melloni, P. Carminati, G. Bianchi, and P. Ferrari. Pharmacological profile of the novel inotropic agent (e,z)-3-((2-aminoethoxy)imino)androstane-6,17-dione hydrochloride (PST2744). The journal of pharmacology and experimental therapeutics. 2002, 303 (2): 592-600.
[2] Suruchi Aditya, Aditya Rattan. Istaroxime: A rising star in acute heart failure. Journal of Pharmacology and Pharmacotherapeutics. 2012, 3(4): 353-355.