cardiac glycoside

Cardiac glycosides inhibit the Na⁺,K⁺ pump. These chemicals are potent poisons that have been used for centuries to induce vomiting.Cardioactive glycosides (such as digoxin, structure shown) have been used to treat congestive heart failure (CHF). Their treatment value is limited by a low therapeutic index: the toxic dose overlaps with the therapeutic dose.

Common source: Foxglove (Digitalis purpurea). There are many other plant sources of cardiac glycosides, including Convallaria majalis (lily of the valley, convallaria), Helleborus niger (black hellebore), Nerium oleander (oleander), Plumeria rubra (frangipani), Strophanthus hispidus and S. kombe (strophanus), Thevetia peruviana (yellow oleander), and Urginea maritima (squill), to name but a few, and the venom of the cane toad (Bufo marinus) also contains cardiac glycosides. The skin and venom glands of the Chinese toads Bufo gargarizans and B. melanostictus is used in a TCM called chansu.

The use of digoxin in heart failure has gradually declined since the Digitalis Investigation Group study showed that digoxin did not reduce overall mortality in heart failure patients (The Digitalis Investigation Group 1997). (source)