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Pharmacology MCQ practice

Core Pharmacology MCQ Practice

Review pharmacodynamics, pharmacokinetics, receptors, efficacy, clearance, bioavailability, and other core pharmacology concepts.

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Sample Questions

Pharmacokinetics

An IV antibiotic infusion is adjusted in renal impairment. Which PK factor best guides the maintenance rate?

  • Receptor affinity
  • Clearance
  • Volume of distribution
  • Drug pKa

Answer: Clearance

Maintenance dosing follows drug clearance.

Volume affects loading dose; pKa affects ionisation; affinity describes receptor binding.

Renal dosing

A patient with acute kidney injury is still receiving digoxin. What is the safest immediate prescribing action?

  • Review dose and check renal function and levels
  • Double the dose for poor perfusion
  • Keep the same dose without checks
  • Stop potassium monitoring

Answer: Review dose and check renal function and levels

Renal impairment increases digoxin accumulation.

Dose escalation, fixed dosing, or ignoring potassium monitoring increases digoxin toxicity risk.

Drug clearance

Which option best describes the main pharmacokinetic concern when a renally cleared drug is given to a patient with severe renal impairment?

  • Reduced receptor reserve
  • Lower oral bioavailability
  • Immediate drug tolerance
  • Accumulation from reduced clearance

Answer: Accumulation from reduced clearance

Reduced renal clearance can cause accumulation and toxicity unless dose is adjusted.

This is not mainly receptor reserve, bioavailability, or immediate tolerance.

Drug clearance

For most drugs showing first-order elimination, which statement is correct?

  • Clearance becomes equal to bioavailability
  • Elimination stops at low concentrations
  • Clearance is relatively constant over the therapeutic range
  • A fixed amount is removed each hour

Answer: Clearance is relatively constant over the therapeutic range

With first-order elimination, elimination amount rises with concentration while clearance stays fairly constant.

A fixed amount per hour describes zero-order behaviour near saturation.

Drug clearance

Which situation best illustrates capacity-limited, zero-order elimination?

  • Target affinity determines elimination
  • A constant amount is eliminated per hour near saturation
  • A constant fraction is eliminated per hour
  • Bioavailability is exactly 100%

Answer: A constant amount is eliminated per hour near saturation

Capacity-limited elimination removes a fixed amount per time once pathways saturate.

A fixed fraction per time is first-order elimination, not zero-order elimination.

Drug-target interaction

Which statement corrects a common misconception about drug-target interaction?

  • The target is always the dose
  • The target is always the route
  • The target is a molecule, not simply the diseased organ
  • The target is always the patient

Answer: The target is a molecule, not simply the diseased organ

The target is the molecular site of action, not simply the affected organ.

Dose, route, and patient are not molecular targets.

Learning Design

Drugzzle uses brief single-best-answer rounds, immediate feedback, confidence reflection, and missed-question review to support retrieval practice and safer prescribing reasoning.