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
In congestive hea failure patients 
Select and explain. 
A. Volume of distribution is increased, B. Hepatic clearance of drugs is not changed, C. Orally administered diuretics may not be effective, may work parenterally, D. Inotropic action of digoxin is attenuated
C: Orally administered diuretics may not be effective, may work parenterally
Answer: C: Orally administered diuretics may not be effective, may work parenterally 
Explanation: Diuretics are given orally in hypeension, given slow iv in CCF for rapid onset of action. Diuretics although donot treat the pathologic changes in HF they are used as main stay for symptomatic treatment to remove excess fluid.Switching to iv or infusion bypasses the GI tract and helps in over coming diuretic resistance. Ref: Goodman and Gillman 13th ed. kidney.