Digitoxin is a medication derived from the leaves of the foxglove plant, specifically Digitalis lanata. It is primarily used to treat heart conditions, particularly heart failure and certain types of arrhythmias. Digitoxin works by increasing the force of heart contractions and regulating heart rhythm. As a cardiac glycoside, digitoxin affects the sodium-potassium ATPase enzyme, leading to increased intracellular calcium levels. This enhances the heart's pumping ability. However, digitoxin has a narrow therapeutic window, meaning that the difference between a therapeutic dose and a toxic dose is small, necessitating careful monitoring during treatment.