digitoxine

Digitoxine is a cardiac glycoside found in the leaves of the foxglove plant (Digitalis spp.). It is a potent medication used to treat certain heart conditions, primarily heart failure and atrial fibrillation. Digitoxine works by increasing the force of contraction of the heart muscle and slowing the heart rate, which can improve symptoms and exercise tolerance in patients with heart failure. In atrial fibrillation, it helps to control the rapid heart rate.

The mechanism of action of digitoxine involves inhibiting the sodium-potassium ATPase pump in heart cells. This leads to an increase in intracellular sodium, which in turn promotes calcium influx. The increased intracellular calcium enhances myocardial contractility.

Digitoxine has a narrow therapeutic index, meaning that the difference between an effective dose and a toxic dose is small. This requires careful monitoring of blood levels and close observation for side effects. Symptoms of digitoxine toxicity can include nausea, vomiting, diarrhea, visual disturbances (such as blurred or yellow vision), and cardiac arrhythmias. Electrolyte imbalances, particularly low potassium levels, can increase the risk of toxicity.

Due to its narrow therapeutic window and potential for toxicity, digitoxine is used less frequently now compared to other cardiac glycosides like digoxin, which has a shorter half-life and is generally considered safer and easier to manage. Digitoxine is typically administered orally. Its metabolism is primarily hepatic, and it is excreted in the urine. The long half-life of digitoxine means that it can persist in the body for a prolonged period.