1. Which process describes the movement of a drug
from the site of administration into the
bloodstream?
A. Distribution
B. Absorption
C. Metabolism
D. Excretion
Answer: B.
Rationale: Absorption is the passage of a drug into
the circulation from the site of administration (Main).
2. A drug’s half-life (t½) is best defined as:
A. Time to peak plasma concentration
B. Time for plasma concentration to decrease by 50%
C. Time until steady state is reached
D. Time for the drug to be excreted unchanged
Answer: B.
Rationale: Half-life is the time required for plasma
concentration to fall by half, key for dosing intervals
(Wikipedia).
3. Which route of administration bypasses first-pass
metabolism?
A. Oral
B. Rectal
C. Sublingual
D. Hepatic
, Answer: C.
Rationale: Sublingual drugs diffuse directly into
systemic circulation, avoiding hepatic first-pass
(Main).
4. Protein binding affects drug distribution by:
A. Increasing free drug concentration
B. Reducing clearance
C. Limiting tissue uptake
D. Enhancing filtration
Answer: C.
Rationale: Highly protein-bound drugs have less free
fraction to cross membranes (Main).
5. A drug that is a competitive antagonist will:
A. Increase the maximum response
B. Decrease potency without affecting efficacy
C. Decrease potency and efficacy
D. Act irreversibly
Answer: B.
Rationale: Competitive antagonists shift the dose-
response curve right (↓ potency) but do not lower the
maximal effect (Wikipedia).
6. Phase I metabolism typically involves:
A. Conjugation
B. Oxidation
C. Glucuronidation
D. Sulfation
Answer: B.
, Rationale: Phase I reactions introduce functional
groups via oxidation, reduction, or hydrolysis (Main).
7. Which organ is the principal site of drug
excretion?
A. Liver
B. Kidney
C. Lung
D. Skin
Answer: B.
Rationale: Kidneys filter and secrete many drugs and
metabolites into urine (Main).
8. Bioavailability refers to:
A. Fraction of unchanged drug reaching systemic
circulation
B. Volume of distribution per kg
C. Rate of metabolism
D. Clearance rate
Answer: A.
Rationale: Bioavailability is the percent of an
administered dose entering circulation unchanged
(Wikipedia).
9. A narrow therapeutic index indicates:
A. Wide margin of safety
B. Little difference between therapeutic and toxic
doses
C. Low potency
D. Rapid excretion
Answer: B.