Question

In a graph of rate of excretion versus plasma drug concentration, which kind of drug will give the below shown curve? (x axis- rate of excretion, y axis – plasma drug concentration)

(a) Drug excreted only by filtration

(b) Drug filtered and actively reabsorbed

(c) Drug filtered as well as actively secreted

(d) Drug reabsorbed actively

I got this question in quiz.

This interesting question is from Drugs Excretion in portion Prodrugs & Excretion of Drugs of Drug Biotechnology

Answer 1

The correct answer is (b) Drug filtered and actively reabsorbed

Best explanation: The drugs which are secreted or reabsorbed, the rate increases with an increase in plasma concentration to a point where saturation occurs. Drugs which are actively reabsorbed, excretion is negligible at low plasma concentration. These agents are excreted in urine when their glomerular filtrate concentration exceeds the active reabsorption capacity e.g. glucose.