Which of the following is the correct definition of first-pass effect of a drug?
A)The point when the total amount of drug in a human does not change over multiple loading does intervals
B)The time it takes for the plasma concentration of drug in the body to be reduced by 50%
C)When a drug is metabolized in the gut wall and liver before it reaches the systemic circulation
D)When a drug is excreted into the urine
Answer: When a drug is metabolized in the gut wall and liver before it reaches the systemic circulation