PHARMACOLOGY FINAL EXAM –
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Section I: General Principles & Pharmacokinetics (Qs 1–10)
1. A drug with zero-order kinetics is administered intravenously. Which
statement is correct?
a) Half-life remains constant regardless of dose
b) A constant amount of drug is eliminated per unit time
c) Elimination rate is directly proportional to drug concentration
d) Doubling the dose doubles the elimination rate
Rationale: Zero-order kinetics means a fixed amount (e.g., 10 mg/hr) is eliminated
regardless of concentration (e.g., phenytoin, alcohol). Half-life increases with dose.
2. A patient has liver cirrhosis and low albumin. The free fraction of a highly
protein-bound drug will:
a) Decrease, requiring lower dose
b) Increase, risking toxicity
c) Remain unchanged
d) Decrease due to increased metabolism
Rationale: Low albumin → less binding → more free (active) drug → increased
effect/toxicity. Dose adjustment may be needed.
3. Which cytochrome P450 enzyme is most commonly involved in drug-drug
interactions?
a) CYP1A2
b) CYP3A4
c) CYP2C9
d) CYP2D6
,Rationale: CYP3A4 metabolizes >50% of drugs (e.g., statins, calcium channel
blockers, benzodiazepines). Inhibitors (grapefruit juice) increase levels.
4. Bioavailability of an oral drug is 50%. IV dose of 10 mg gives plasma level
of 2 mg/L. To achieve same plasma level orally, what dose is needed?
a) 5 mg
b) 20 mg
c) 10 mg
d) 15 mg
Rationale: Bioavailability (F) = (oral dose/IV dose) × 100%. To achieve same
effect: oral dose = IV dose / F = 10 mg / 0.5 = 20 mg.
5. A drug has a volume of distribution (Vd) of 0.2 L/kg. This suggests:
a) Primarily in plasma
b) Sequestered in fat
c) Bound to tissues
d) Crosses blood-brain barrier easily
Rationale: Vd ~0.07 L/kg = plasma; 0.2 L/kg = extracellular fluid; >0.6 L/kg =
tissue binding. Low Vd means drug stays in blood (e.g., warfarin).
6. The therapeutic index (TI) is calculated as:
a) ED50/TD50
b) TD50/ED50
c) LD50/ED50
d) ED50/LD50
Rationale: TI = Toxic dose for 50% / Effective dose for 50%. Higher TI = safer.
Warfarin low TI; penicillin high TI.
7. Which transporter mediates renal secretion of many drugs?
a) P-glycoprotein
b) Organic anion transporter (OAT)
c) GLUT4
d) Na+/K+ ATPase
Rationale: OATs in proximal tubule secrete acidic drugs (e.g., penicillins,
methotrexate). Probenecid inhibits OAT, increasing penicillin levels.
8. A drug with a half-life of 4 hours reaches steady state in approximately:
a) 8 hours
, b) 20 hours
c) 40 hours
d) 12 hours
Rationale: Steady state ≈ 4–5 half-lives → 4 × 5 = 20 hours.
9. First-pass effect reduces bioavailability of which route?
a) Intravenous
b) Sublingual
c) Oral
d) Transdermal
Rationale: Oral drugs pass through liver via portal circulation → metabolism
before systemic circulation. Sublingual/IV bypass this.
10. Grapefruit juice increases levels of simvastatin by inhibiting:
a) CYP2D6
b) CYP3A4 in gut wall
c) P-glycoprotein only
d) CYP1A2
Rationale: Grapefruit inhibits intestinal CYP3A4 → reduced presystemic
metabolism → higher simvastatin → risk myopathy.
Section II: Autonomic Nervous System (Qs 11–20)
11. A patient with bradycardia receives atropine. The mechanism is:
a) Beta-1 agonist
b) Muscarinic antagonist
c) Alpha-1 agonist
d) Nicotinic agonist
Rationale: Atropine blocks M2 receptors in SA node → increased heart rate.
12. Which drug causes miosis, bradycardia, and bronchoconstriction?
a) Atropine
b) Pilocarpine
c) Epinephrine
d) Albuterol
Questions And Answers With
Rationales/Graded A+/2026
Update/100% Correct /Instant
Download
Section I: General Principles & Pharmacokinetics (Qs 1–10)
1. A drug with zero-order kinetics is administered intravenously. Which
statement is correct?
a) Half-life remains constant regardless of dose
b) A constant amount of drug is eliminated per unit time
c) Elimination rate is directly proportional to drug concentration
d) Doubling the dose doubles the elimination rate
Rationale: Zero-order kinetics means a fixed amount (e.g., 10 mg/hr) is eliminated
regardless of concentration (e.g., phenytoin, alcohol). Half-life increases with dose.
2. A patient has liver cirrhosis and low albumin. The free fraction of a highly
protein-bound drug will:
a) Decrease, requiring lower dose
b) Increase, risking toxicity
c) Remain unchanged
d) Decrease due to increased metabolism
Rationale: Low albumin → less binding → more free (active) drug → increased
effect/toxicity. Dose adjustment may be needed.
3. Which cytochrome P450 enzyme is most commonly involved in drug-drug
interactions?
a) CYP1A2
b) CYP3A4
c) CYP2C9
d) CYP2D6
,Rationale: CYP3A4 metabolizes >50% of drugs (e.g., statins, calcium channel
blockers, benzodiazepines). Inhibitors (grapefruit juice) increase levels.
4. Bioavailability of an oral drug is 50%. IV dose of 10 mg gives plasma level
of 2 mg/L. To achieve same plasma level orally, what dose is needed?
a) 5 mg
b) 20 mg
c) 10 mg
d) 15 mg
Rationale: Bioavailability (F) = (oral dose/IV dose) × 100%. To achieve same
effect: oral dose = IV dose / F = 10 mg / 0.5 = 20 mg.
5. A drug has a volume of distribution (Vd) of 0.2 L/kg. This suggests:
a) Primarily in plasma
b) Sequestered in fat
c) Bound to tissues
d) Crosses blood-brain barrier easily
Rationale: Vd ~0.07 L/kg = plasma; 0.2 L/kg = extracellular fluid; >0.6 L/kg =
tissue binding. Low Vd means drug stays in blood (e.g., warfarin).
6. The therapeutic index (TI) is calculated as:
a) ED50/TD50
b) TD50/ED50
c) LD50/ED50
d) ED50/LD50
Rationale: TI = Toxic dose for 50% / Effective dose for 50%. Higher TI = safer.
Warfarin low TI; penicillin high TI.
7. Which transporter mediates renal secretion of many drugs?
a) P-glycoprotein
b) Organic anion transporter (OAT)
c) GLUT4
d) Na+/K+ ATPase
Rationale: OATs in proximal tubule secrete acidic drugs (e.g., penicillins,
methotrexate). Probenecid inhibits OAT, increasing penicillin levels.
8. A drug with a half-life of 4 hours reaches steady state in approximately:
a) 8 hours
, b) 20 hours
c) 40 hours
d) 12 hours
Rationale: Steady state ≈ 4–5 half-lives → 4 × 5 = 20 hours.
9. First-pass effect reduces bioavailability of which route?
a) Intravenous
b) Sublingual
c) Oral
d) Transdermal
Rationale: Oral drugs pass through liver via portal circulation → metabolism
before systemic circulation. Sublingual/IV bypass this.
10. Grapefruit juice increases levels of simvastatin by inhibiting:
a) CYP2D6
b) CYP3A4 in gut wall
c) P-glycoprotein only
d) CYP1A2
Rationale: Grapefruit inhibits intestinal CYP3A4 → reduced presystemic
metabolism → higher simvastatin → risk myopathy.
Section II: Autonomic Nervous System (Qs 11–20)
11. A patient with bradycardia receives atropine. The mechanism is:
a) Beta-1 agonist
b) Muscarinic antagonist
c) Alpha-1 agonist
d) Nicotinic agonist
Rationale: Atropine blocks M2 receptors in SA node → increased heart rate.
12. Which drug causes miosis, bradycardia, and bronchoconstriction?
a) Atropine
b) Pilocarpine
c) Epinephrine
d) Albuterol
