Correct Answer: C

Rationale:
Choice C is correct because drugs with a significant first-pass effect undergo extensive liver metabolism after oral administration, reducing bioavailability and often leaving minimal active drug for systemic effects.
Choice A is incorrect as these drugs can be given IV to avoid first-pass metabolism, not just orally.
Choice B is wrong because they pass through hepatic circulation, not bypass it.
Choice D is incorrect since first-pass typically inactivates drugs, not converts them to more active forms.

Correct Answer: C

Rationale:
Choice C is correct because receptor antagonists, like beta blockers, block agonist effects, partially inhibiting their action without activating the receptor themselves.
Choice A is incorrect as downregulation isn't typical; antagonists may cause upregulation.
Choice B is wrong because abrupt discontinuation may cause rebound effects, but it's not their defining property.
Choice D is incorrect since antagonists reduce, not exaggerate, responses to agonists.

Correct Answer: B

Rationale:
Choice B is correct because steady state occurs when drug input (absorption) equals output (excretion), maintaining constant levels over time.
Choice A is incorrect as absorption exceeding excretion describes initial dosing, not steady state.
Choice C is wrong because steady state can be therapeutic or toxic, not just below toxicity.
Choice D is incorrect since only B defines steady state accurately.

Correct Answer: A

Rationale:
Choice A is correct because sodium bicarbonate, a basic substance, is absorbed more in the intestines' neutral-to-alkaline environment than the stomach's acidic pH, where it's neutralized.
Choice B is incorrect as ascorbic acid (vitamin
C) is acidic and better absorbed in the stomach.
Choice C is wrong because salicylic acid, also acidic, favors stomach absorption.
Choice D is incorrect since glucose absorption occurs throughout the gut, not predominantly intestines.

Correct Answer: C

Rationale:
Choice C is correct because the WHO's prescribing process begins with diagnosing the patient's problem, ensuring treatment is based on an accurate assessment.
Choice A is incorrect as choosing treatment follows diagnosis.
Choice B is wrong because education comes after prescribing.
Choice D is incorrect since starting treatment is the final step, not the first.