This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
The half-life of Digoxin is 
Select and explain. 
A. 24hours, B. 40hours, C. 48hours, D. 60hours
B: 40hours
Answer: B: 40hours 
Explanation: Digoxin is not extensively metabolized in humans; almost two-thirds is excreted unchanged by the kidneys. Its renal clearance is propoional to creatinine clearance, and the half-life is 36-40 hours in patients with normal renal functionReference: Katzung Pharmacology; 13th edition; Chapter 13; Drugs Used in Hea Failure