Digoxins

Digoxins are a class of naturally occurring compounds found in plants, most notably in the Digitalis genus. These compounds, also known as cardiac glycosides, have been used for centuries in traditional medicine for their effects on the heart. The most well-known digoxin molecule, simply referred to as digoxin, is a specific cardiac glycoside derived from the foxglove plant.

The primary mechanism of action for digoxins involves inhibiting the sodium-potassium ATPase pump in cardiac muscle cells. This inhibition leads to an increase in intracellular sodium concentration, which in turn affects the sodium-calcium exchanger. The net result is an increase in intracellular calcium. Elevated calcium levels enhance the force of myocardial contraction, a phenomenon known as positive inotropy. Additionally, digoxins can slow the heart rate by increasing vagal tone and decreasing conduction through the atrioventricular node, acting as a negative chronotropic and dromotropic agent.

Clinically, digoxin has been used in the management of heart failure and certain types of arrhythmias, particularly atrial fibrillation. Its ability to improve cardiac output and control ventricular rate in atrial fibrillation has made it a valuable therapeutic agent. However, digoxin has a narrow therapeutic index, meaning the difference between an effective dose and a toxic dose is small. This necessitates careful monitoring of blood levels and clinical signs to avoid toxicity. Symptoms of digoxin toxicity can range from gastrointestinal disturbances and visual changes to severe cardiac arrhythmias. Due to the availability of newer and safer medications, the use of digoxin has become more restricted in recent years, often reserved for specific patient populations or refractory cases.