Questions with Correct Verified Answers/ Rated A+
1. Pharmacokinetics is best defined as:
A) The study of the biological and therapeutic effects of drugs
B) The study of the absorption, distribution, metabolism, and
excretion of drugs
C) The study of the mechanisms of drug action
D) The study of drug interactions at receptor sites
Answer: B
Rationale: Pharmacokinetics is the study of what the body does to
the drug. It encompasses absorption, distribution, metabolism, and
excretion (ADME). Pharmacodynamics, in contrast, is the study of
what the drug does to the body .
2. Pharmacodynamics involves the study of:
A) Drug absorption and distribution
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,B) The mechanisms of drug action and the biological and
therapeutic effects of drugs
C) Drug metabolism and excretion
D) The chemical structure of medicinal agents
Answer: B
Rationale: Pharmacodynamics involves the study of the biological
and therapeutic effects of drugs and their mechanisms of action.
This includes receptor binding, signal transduction, and the resulting
physiological responses .
3. The main mechanism of absorption for most drugs in the GI
tract is:
A) Active transport
B) Filtration (aqueous diffusion)
C) Endocytosis
D) Passive diffusion (lipid diffusion)
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,Answer: D
Rationale: Most drugs are absorbed in the GI tract by passive
diffusion (lipid diffusion). Unionized, lipophilic drugs readily cross
cell membranes. The absorption of weak acids and bases depends
on their pKa and the pH of the environment .
4. Which of the following statements about drug absorption is
correct?
A) Unionized drugs are liposoluble and can diffuse through
membranes
B) The acid environment of the stomach slows the absorption of
acetylsalicylic acid
C) Polar drugs pass through membranes more easily than non-
polar drugs
D) Facilitated diffusion requires energy
Answer: A
Rationale: Unionized drugs are generally liposoluble and can
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, readily diffuse through cell membranes. The acid environment of the
stomach actually enhances the absorption of weak acids like
acetylsalicylic acid (aspirin), not slows it .
5. Bioavailability is defined as:
A) The amount of drug that reaches the systemic circulation
B) The amount of drug metabolized in the liver before reaching
the systemic circulation
C) The amount of drug bound to plasma proteins
D) The amount of drug excreted unchanged in the urine
Answer: A
Rationale: Bioavailability is the fraction of an administered dose of
a drug that reaches the systemic circulation in an unchanged form.
It depends on the extent of absorption and the degree of first-pass
metabolism .
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