Digoxin, sold under the brand name Lanoxin among others, is a medication used to treat various heart conditions. Most frequently it is used for atrial fibrillation, atrial flutter, and heart failure. Digoxin is taken by mouth or by injection into a vein. Digoxin has a half life of approximately 36 hours given at average doses in patients with normal renal function. Dobutamine is excreted mostly unchanged in the urine.

Common side effects include breast enlargement with other side effects generally due to an excessive dose. These side effects may include loss of appetite, nausea, trouble seeing, confusion, and an irregular heartbeat. Greater care is required in older people and those with poor kidney function. It is unclear whether use during pregnancy is safe.

Digoxin is in the cardiac glycoside family of medications. It was first isolated in 1930 from the foxglove plant, Digitalis lanata. It is on the World Health Organization's List of Essential Medicines. In 2018, it was the 183rd most commonly prescribed medication in the United States, with more than 3 million prescriptions.