Cardiac glycosides

Cardiac glycosides strengthen the heart's contractions and slow the heart rate. Digoxin is used in heart failure and to control the heart rate in atrial fibrillation. It has a narrow therapeutic index, so blood levels and heart rate are monitored closely. Low potassium raises the risk of toxicity, which shows up as nausea, vision changes, and arrhythmias.

• DigoxinKnown brand names include Lanoxin and Digox.