Digoxin is one of the cardiac (or digitalis) glycosides, a closely related group of drugs having in common specific effects on the myocardium. These drugs are found in a number of plants. Digoxin is extracted from the leaves of Digitalis lanata. The term "digitalis" is used to designate the whole group of glycosides. The glycosides are composed of two portions: a sugar and a cardenolide (hence "glycosides"). Digoxin exists as odorless white crystals that melt with decomposition above 230°C. The drug is practically insoluble in water and in ether; slightly soluble in diluted (50%) alcohol and in chloroform; and freely soluble in pyridine.
Digoxin is a drug used to treat some heart problems. One of these problems, heart failure, results when the heart can't pump blood well enough to supply the body's needs. If you have heart failure, digoxin can improve your heart's ability to pump blood. Better pumping of the heart will often improve symptoms such as shortness of breath. Digoxin can also help a rapid or irregular heartbeat, such as atrial fibrillation (sometimes called "a-fib"). Digoxin helps by slowing down and controlling the heart rate.
Digoxin is extracted from the leaves of a plant called digitalis lanata. Digoxin increases the strength and vigor of the heart muscle contractions, and is useful in the treatment of heart failure. Digoxin also slows the electrical conduction between the atria and the ventricles of the heart, and is useful in treating abnormally rapid atrial rhythms such as atrial fibrillation, atrial flutter, and atrial tachycardia. Digoxin is used to treat congestive heart failure and the associated symptoms of shortness of breath when lying flat, wheezing, and ankle swelling. Digoxin is also used to slow heart rate in rapid atrial rhythm disturbances such as atrial fibrillation and atrial flutter.
Abnormally rapid atrial rhythms can be caused by heart attacks, excessive thyroid hormones, alcoholism, infections, and many other conditions. During rapid atrial rhythms, electrical signals from the atria cause rapid contractions of the ventricles. Rapid ventricle contractions are inefficient in delivering oxygen and nutrients to the body, causing symptoms of weakness, shortness of breath, dizziness, and even chest pain. Digoxin alleviates these symptoms by blocking the electrical conduction between the atria and ventricles, thus slowing ventricle contractions. Digoxin binds to and inhibits the sodium/potassium-ATPase (sodium pump) within the plasma membrane of cardiac myocytes. This inhibition increases the intracellular sodium content which in turn increases the intracellular calcium content which leads to increased cardiac contractility. Digoxin has other effects on the heart, particularly on its electrical activity. It also affects the contractile function of vascular smooth muscle and the activity of the autonomic nervous system.