Question

The first-pass metabolism refers to:

• A. Drug metabolism in the liver before reaching systemic circulation
• B. Drug absorption in the gastrointestinal tract
• C. Drug excretion through the kidneys
• D. Drug distribution to tissues

Hint:

First-pass metabolism significantly reduces the bioavailability of orally administered drugs.

Answer 1

The Correct Option is A

The first-pass metabolism refers to the process where drugs are metabolized in the liver before they reach the systemic circulation. After absorption through the gastrointestinal tract, drugs are carried by the portal vein to the liver, where they may be metabolized, thus reducing the concentration of the drug before it reaches the bloodstream. Therefore, the correct answer is: \[ \boxed{(A) \, \text{Drug metabolism in the liver before reaching systemic circulation}} \]