The digoxin tablet is usually taken once a day. Digoxin is derived from the leaves of a digitalis plant. Digoxin helps make the heart beat stronger and with a more regular rhythm. Digoxin is used to treat heart failure. The tablet is a prescription medication that's used to treat atrial fibrillation (an irregular heart rhythm) and heart failure. It's a type of drug called an antiarrhythmic. Digoxin tablet is also used to treat certain types of irregular heartbeat (such as chronic atrial fibrillation ).