ouabain

Ouabain is a plant-derived cardiac glycoside traditionally extracted from the seeds of Strophanthus gratus and related species. It has been used medically for the treatment of congestive heart failure, atrial fibrillation, atrial flutter, and other supraventricular arrhythmias. Ouabain acts by inhibiting the sodium/potassium-transporting ATPase (Na^+/K^+-ATPase) membrane pump in cardiac myocytes. This inhibition leads to increased intracellular sodium concentration which reduces the activity of the sodium-calcium exchanger (NCX), resulting in elevated intracellular calcium levels. The increase in calcium enhances myocardial contractility (positive inotropic effect) and can affect cardiac electrical activity by increasing phase 4 depolarization slope and shortening action potential duration[1][5][6]. Due to its high toxicity and narrow therapeutic window, ouabain is rarely used clinically today except experimentally or in specific regions such as Taiwan and Germany[7]. It has also been studied for its effects on cellular processes beyond cardiology, including modulation of integrins in cancer cells and as an adjunct therapy against drug-resistant tuberculosis[4][9].

Brand names

Ouabain

Other names

g-strophanthingamma-strophanthin