DIGOXIN (Lanoxin)

Cardiac glycosides; Used to treat HF

Strengthens heart contractions (Inhibits Na+/K+ pump so more Ca2+ can enter cardiac cells --> stronger contractions) + inotropic effect (stronger contractions) -chrono tropic effects (slows HR) -dromo tropic effects=slows conduction Increases SV

PO: 0.5-1mg initially, then 0.125-0.5mg/ day IV: give same dose over 5 minute span.

Certain drugs may increase the serum level of digoxin (quinidine, verapamil due to receptor site competition and enzyme pathways). Certain drugs lower serum level of digoxin (anatacids and colestipol decrease absorption) Certain drugs increase risk for digoxin toxicity (thiazide, loop diuretics). Risk for toxicity if hypokalemia, hypomagnesemia, or hypercalcemia ** LOW K+ ENHANCES ACTION OF DIGOXIN** Herbs can also have interactions

Digoxin toxicity: bradycardia, AV block, dysrhythmias, n/v, blurry vision, illusions, h/a, confusion, delirium. More at risk for toxicity if elderly.