Lanoxin is a medication commonly prescribed for the treatment of heart failure and irregular heartbeats. The active ingredient in Lanoxin is digoxin. Synonyms for Lanoxin include digoxin, digitalis, and Lanoxicaps. These medications are derived from the leaves of the Digitalis purpurea plant and work to strengthen the contractions of the heart, regulating the heartbeat. Lanoxin is often prescribed to treat symptoms associated with atrial fibrillation and other heart conditions. As with any medication, it is essential to use Lanoxin only as prescribed and to follow all instructions from your healthcare provider to ensure proper dosage and avoid any potential side effects.