Definition of pharmacology MCQs With Answer

Introduction: The “Definition of pharmacology MCQs With Answer” is a focused learning resource for B.Pharm students covering pharmacology fundamentals and applied concepts. This concise guide emphasizes the definition of pharmacology, branches like pharmacodynamics and pharmacokinetics, ADME (absorption, distribution, metabolism, excretion), drug-receptor interactions, dose–response, therapeutic index, adverse drug reactions, and clinical relevance. Questions are designed to reinforce core terminology, mechanisms, and calculations encountered in pharmacy practice and exams. Clear answers help build accurate conceptual understanding and exam readiness. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the definition of pharmacology?

• The study of drug discovery only
• The study of drugs, their properties, effects, and therapeutic uses
• The study of herbal medicines exclusively
• The study of pharmaceutical marketing

Correct Answer: The study of drugs, their properties, effects, and therapeutic uses

Q2. Which branch of pharmacology studies the effects of drugs on living systems?

• Pharmaceutics
• Pharmacognosy
• Pharmacodynamics
• Pharmacokinetics

Correct Answer: Pharmacodynamics

Q3. Which term describes the study of drug absorption, distribution, metabolism, and excretion?

• Pharmacodynamics
• Pharmacokinetics
• Toxicology
• Clinical pharmacy

Correct Answer: Pharmacokinetics

Q4. What does ADME stand for?

• Absorption, Distribution, Metabolism, Excretion
• Administration, Dosing, Monitoring, Evaluation
• Absorption, Drug interaction, Metabolism, Efficacy
• Allocation, Distribution, Measurement, Elimination

Correct Answer: Absorption, Distribution, Metabolism, Excretion

Q5. Which parameter describes the fraction of an administered dose reaching systemic circulation?

• Volume of distribution
• Clearance
• Bioavailability
• Half-life

Correct Answer: Bioavailability

Q6. Which is the best definition of half-life (t1/2)?

• Time for drug dose to be absorbed completely
• Time for blood concentration to decrease by 10%
• Time for plasma concentration to decrease by 50%
• Time for drug to be excreted unchanged

Correct Answer: Time for plasma concentration to decrease by 50%

Q7. Volume of distribution (Vd) primarily reflects which concept?

• Extent of drug binding to receptors
• Extent of drug distribution between plasma and tissues
• Rate of drug metabolism by liver enzymes
• Rate of renal excretion

Correct Answer: Extent of drug distribution between plasma and tissues

Q8. Which organ is the major site for drug metabolism?

• Kidney
• Liver
• Spleen
• Pancreas

Correct Answer: Liver

Q9. Which phase of hepatic metabolism typically involves functionalization reactions (e.g., oxidation)?

• Phase I metabolism
• Phase II metabolism
• Renal phase
• Gastric phase

Correct Answer: Phase I metabolism

Q10. What is a prodrug?

• A drug that is inactive until metabolized into an active form
• A drug that is already active and not metabolized
• A drug exclusively for topical use
• A drug that causes allergic reactions

Correct Answer: A drug that is inactive until metabolized into an active form

Q11. Which term defines the intensity of drug effect at a given concentration?

• Potency
• Toxicity
• Efficacy
• Bioavailability

Correct Answer: Efficacy

Q12. Which term refers to the amount of drug required to produce a defined effect?

• Efficacy
• Potency
• Therapeutic index
• First-pass effect

Correct Answer: Potency

Q13. What does the therapeutic index compare?

• Potency versus efficacy
• LD50 to ED50 (lethal dose to effective dose)
• Absorption rate versus elimination rate
• Oral bioavailability versus IV bioavailability

Correct Answer: LD50 to ED50 (lethal dose to effective dose)

Q14. Which type of antagonist competes with an agonist at the same receptor binding site?

• Noncompetitive antagonist
• Physiological antagonist
• Competitive antagonist
• Allosteric agonist

Correct Answer: Competitive antagonist

Q15. What characterizes a noncompetitive antagonist?

• Reversible binding to the agonist site only
• Irreversible or allosteric binding reducing maximal response
• Enhancement of agonist potency
• Increases drug bioavailability

Correct Answer: Irreversible or allosteric binding reducing maximal response

Q16. Which term describes decreased response after repeated drug exposure requiring higher doses?

• Tachyphylaxis
• Tolerance
• Idiosyncrasy
• Sensitization

Correct Answer: Tolerance

Q17. Rapid desensitization to a drug over minutes to hours is called:

• Tolerance
• Tachyphylaxis
• Idiosyncrasy
• Cumulative toxicity

Correct Answer: Tachyphylaxis

Q18. Which route avoids first-pass hepatic metabolism?

• Oral
• Sublingual
• Enteric-coated oral
• First-pass is unavoidable

Correct Answer: Sublingual

Q19. Which process primarily determines renal excretion of a drug?

• Liver enzyme induction
• Glomerular filtration, tubular secretion, and reabsorption
• Gastric emptying only
• Plasma protein binding exclusively

Correct Answer: Glomerular filtration, tubular secretion, and reabsorption

Q20. Which plasma protein most commonly binds acidic drugs?

• Alpha-1-acid glycoprotein
• Albumin
• Globulin
• Hemoglobin

Correct Answer: Albumin

Q21. Which receptor theory suggests response is proportional to receptor occupancy?

• Modified occupancy theory
• Receptor reserve theory
• Classical occupancy theory
• Biophase theory

Correct Answer: Classical occupancy theory

Q22. What are spare receptors?

• Receptors present only in diseased tissues
• Excess receptors so maximal response occurs without full occupancy
• Receptors permanently blocked by antagonists
• Receptors found only in the nucleus

Correct Answer: Excess receptors so maximal response occurs without full occupancy

Q23. Which is an example of a phase II metabolic reaction?

• Oxidation by CYP450
• Glucuronidation
• Hydrolysis by esterases
• Reduction by nitroreductase

Correct Answer: Glucuronidation

Q24. Enzyme induction typically results in which effect on drug concentrations?

• Increased plasma concentration of substrate drugs
• Decreased plasma concentration of substrate drugs
• No change in concentration
• Immediate allergic reactions

Correct Answer: Decreased plasma concentration of substrate drugs

Q25. Which describes a Type A adverse drug reaction?

• Predictable and dose-related
• Unpredictable and immune-mediated
• Genetic idiosyncratic reaction
• Purely psychosomatic effect

Correct Answer: Predictable and dose-related

Q26. What is pharmacovigilance primarily concerned with?

• Drug pricing strategies
• Monitoring and prevention of adverse drug reactions
• Drug formulation manufacturing only
• Advertising of pharmaceutical products

Correct Answer: Monitoring and prevention of adverse drug reactions

Q27. Which term describes a genetically determined abnormal reaction to a drug?

• Tolerance
• Idiosyncrasy
• Synergism
• Dependence

Correct Answer: Idiosyncrasy

Q28. Which interaction results when two drugs produce a greater effect than the sum of individual effects?

• Antagonism
• Synergism
• Additive effect
• Neutralization

Correct Answer: Synergism

Q29. What is the primary effect of first-pass metabolism?

• Enhances bioavailability of all drugs
• Reduces oral bioavailability due to hepatic metabolism before systemic circulation
• Increases drug half-life substantially
• Prevents renal excretion

Correct Answer: Reduces oral bioavailability due to hepatic metabolism before systemic circulation

Q30. An inverse agonist at a receptor does what?

• Produces the same response as an agonist
• Blocks the receptor but has no intrinsic activity
• Stabilizes the receptor in an inactive conformation reducing constitutive activity
• Enhances constitutive receptor activity

Correct Answer: Stabilizes the receptor in an inactive conformation reducing constitutive activity