What is digitalis?

   Digitalis is a drug prepared from the dried leaves of the common foxglove (Digitalis purpurea). Digitalis is one of a series of related cardiac glycosides that are used primarily for the treatment of congestive heart failure. The drug acts by increasing the contractile strength of the heart muscle and by allowing the heart to work more efficiently. It increases the rate of entry of calcium ions into the individual muscle fibers, and this may account for its beneficial effects.
   As a result of the action of digitalis the failing heart beats more slowly and regularly and pumps an increased volume of blood. Digitalis is extremely toxic, and the doses, which are usually administered orally in powder or tincture form, must be individually determined.