Digoxin is a cardiac glycoside obtained from foxglove plant. It is used to treat heart failure and regulate heart rate in some heart rhythm disorders.
In heart failure, digoxin helps the heart to contract more powerfully and pump more blood round the body. Although digoxin reduces the need for hospital admissions it has no effect on mortality. There are other heart failure drugs with proven mortality benefit, such as ACE inhibitors, beta-blockers and aldosterone antagonists, which should therefore be used before digoxin is considered.
In atrial fibrillation and to a limited extent in atrial flutter, digoxin slows down and regulates heart rate which helps in reducing symptoms of palpitations. However, digoxin works mainly in sedentary patients and has less effect on fast heart rate on exertion or stress, therefore beta-blockers or calcium channel blockers verapamil and diltiazem should be first choice in atrial fibrillation. The strongest indication for digoxin is in patients with both heart failure and atrial fibrillation.
Treatment with digoxin
At the start, you may be kept on somewhat high doses for about a week. Then, after a week, your GP or Consultant will adjust its dose in accordance with your condition. The dose of digoxin depends on your kidney function and size. Digoxin may interact with other medications, especially with verapamil and amiodarone which are also often used in treatment of arrhythmias and with the antibiotic erythromycin.
The side effects of digoxin are relatively frequent due to its narrow margin between effectiveness and toxicity. Common adverse effects are nausea, vomiting and diarrhea, confusion and drowsiness. Arrhythmias can occur especially in presence of low level of potassium in blood.