List of products in the National Drug Code with proprietary name . Digoxin is used to treat heart failure, usually along with other medications. It is also used to treat certain types of irregular heartbeat (such as chronic atrial fibrillation). Treating heart failure may help maintain your ability to walk and exercise and may improve the strength of your heart. Treating an irregular heartbeat can also improve your ability to exercise. Digoxin belongs to a class of medications called cardiac glycosides. It works by affecting certain minerals (sodium and potassium) inside heart cells. This reduces strain on the heart and helps it maintain a normal, steady, and strong heartbeat.