Question

In a graph of renal clearance versus plasma drug concentration, which kind of drug will give the below shown curve?

(a) Drug excreted only by filtration

(b) Drug filtered and actively reabsorbed

(c) Drug filtered as well as actively secreted

(d) Drug reabsorbed actively

This question was addressed to me in an interview for internship.

My question is from Drugs Excretion in chapter Prodrugs & Excretion of Drugs of Drug Biotechnology

Answer 1

Right answer is (a) Drug excreted only by filtration

The best explanation: Glomerular filtration and reabsorption from the further tubules are directly affected by plasma drug concentration. A drug that will not be bound to the plasma proteins and excreted by only filtration will have linear relationship between the rate of excretion and plasma drug concentration.