Digitalis glycoside is a type of medication used to treat heart-related conditions, such as heart failure, atrial fibrillation and flutter. This medication works by slowing down the heart rate and increasing its strength in pumping blood. The most common type of digitalis glycoside is digoxin. Other synonyms for digitalis glycoside include cardiac glycosides, digitalis medications, digitalis preparations, and cardenolides. These words are often used interchangeably to refer to medications that contain digitoxin or digoxin as their active ingredient. Though these medications are effective in treating heart-related issues, they must be used with caution as they can cause serious side effects if not taken as prescribed by a doctor.