Enzymes in this class are ATPases that are involved in catalyzing transmembrane movement of substances, e.g. the exchange of extracellular potassium (K⁺) for cytoplasmic ions, being either Na⁺ and/or Ca²⁺ (EC 3.6.3.9) in order to maintain the resting potential avail transport, and regulate cellular volume, or H⁺ (EC 3.6.3.10) in order to promote gastric acid secretion. Digoxin (Axon 1649) and its active metabolite (Axon 1695) for example, are known to be a unique medication with pharmacological effects resulting in hemodynamic, sympatholytic, and electrophysiologic changes. Their primary mechanism of action is inhibition of the Na⁺/K⁺ ATPase pump, thereby promoting Na⁺/Ca²⁺ exchange, which results in an influx of intracellular Ca²⁺ and increased myocardial contraction[1]. Besides this, recent studies revealed that digoxin also targets the transcription factor Hypoxia inducible factor HIF-1 by potently inhibiting HIF-1α mRNA translation. As a result, Digoxin administration increased latency and decreased growth of tumor xenografts, whereas treatment of established tumors resulted in growth arrest within one week[2].