Application in Pharmacokinetics MCQs With Answer

Application in Pharmacokinetics MCQs With Answer offers B. Pharm students a focused review of key concepts in drug absorption, distribution, metabolism, and excretion. This concise, application-oriented introduction emphasizes bioavailability, clearance, volume of distribution, half-life, compartment models, dosing calculations, therapeutic drug monitoring, and nonlinear kinetics. Each MCQ explores practical problem-solving, interpretation of PK parameters (AUC, Cmax, Tmax, CL, Vd, ke), and clinical implications like drug interactions, renal/hepatic impairment, and dosage adjustment. Ideal for exam preparation and revision, these questions strengthen understanding of both theory and calculations used in real-world pharmacokinetic assessments. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. In pharmacokinetics, bioavailability (F) is best defined as:

• The fraction of an administered dose that reaches systemic circulation in an active form
• The volume in which a drug distributes
• The rate at which a drug is eliminated
• The area under the plasma concentration–time curve

Correct Answer: The fraction of an administered dose that reaches systemic circulation in an active form

Q2. The one-compartment IV bolus equation for plasma concentration at time t is:

• C(t) = C0 × e^(−ke × t)
• C(t) = (Dose/Vd) × (1 − e^(−ke × t))
• C(t) = (Ka/(Ka − ke)) × (e^(−ke × t) − e^(−Ka × t))
• C(t) = AUC × CL

Correct Answer: C(t) = C0 × e^(−ke × t)

Q3. For a drug that follows first-order elimination, half-life (t1/2) is related to the elimination rate constant (ke) by:

• t1/2 = 0.693 / ke
• t1/2 = ke / 0.693
• t1/2 = Vd / CL
• t1/2 = Dose / AUC

Correct Answer: t1/2 = 0.693 / ke

Q4. Total clearance (CL) can be calculated from intravenous data using:

• CL = Dose / AUC
• CL = Vd × ke
• CL = Cmax / Tmax
• CL = Ka / ke

Correct Answer: CL = Dose / AUC

Q5. Volume of distribution (Vd) provides information about:

• Extent of drug distribution into tissues relative to plasma
• Rate of absorption after oral dosing
• Hepatic extraction ratio
• Renal clearance mechanism

Correct Answer: Extent of drug distribution into tissues relative to plasma

Q6. Bioavailability (F) from oral versus IV dosing is calculated by:

• F = (AUCpo / Dosepo) / (AUCiv / Doseiv)
• F = Dosepo / Doseiv
• F = Cmaxpo / Cmaxiv
• F = Vd / CL

Correct Answer: F = (AUCpo / Dosepo) / (AUCiv / Doseiv)

Q7. If a drug has a large Vd (> total body water), this suggests:

• Extensive tissue distribution and binding
• Drug confined mainly to plasma
• Very high protein binding in plasma only
• Rapid renal excretion

Correct Answer: Extensive tissue distribution and binding

Q8. The relationship CL = ke × Vd implies that:

• Clearance depends on both elimination rate and distribution volume
• Vd equals clearance divided by half-life
• Ke is independent of clearance
• Clearance increases with decreased Vd only

Correct Answer: Clearance depends on both elimination rate and distribution volume

Q9. Steady state during repeated dosing is typically achieved after approximately:

• 4–5 half-lives
• 1–2 half-lives
• 10–12 half-lives
• Immediate after first dose

Correct Answer: 4–5 half-lives

Q10. Loading dose is used to quickly achieve target concentration and is calculated as:

• Loading dose = Vd × target concentration / F
• Loading dose = CL × target concentration × dosing interval
• Loading dose = Dose / AUC
• Loading dose = 0.693 / ke

Correct Answer: Loading dose = Vd × target concentration / F

Q11. Maintenance dose rate to maintain steady-state concentration is best expressed as:

• Rate = CL × Css / F
• Rate = Vd × Css / F
• Rate = Dose / AUC
• Rate = 0.693 × Vd

Correct Answer: Rate = CL × Css / F

Q12. A drug showing zero-order elimination means:

• A constant amount is eliminated per unit time regardless of concentration
• A constant fraction is eliminated per unit time
• Elimination follows first-order kinetics at all concentrations
• Elimination rate depends on renal clearance only

Correct Answer: A constant amount is eliminated per unit time regardless of concentration

Q13. The accumulation ratio at steady state for first-order kinetics with dosing interval τ is:

• 1 / (1 − e^(−ke × τ))
• e^(−ke × τ)
• ke / (ke + Ka)
• Vd / CL

Correct Answer: 1 / (1 − e^(−ke × τ))

Q14. Hepatic clearance (CLh) for a drug is determined by hepatic blood flow (Qh) and extraction ratio (ER) using:

• CLh = Qh × ER
• CLh = Vd × ke
• CLh = Dose / AUC
• CLh = Ka × F

Correct Answer: CLh = Qh × ER

Q15. A drug with high extraction ratio (>0.7) will have hepatic clearance largely limited by:

• Hepatic blood flow
• Plasma protein binding
• Intrinsic clearance only
• Renal function

Correct Answer: Hepatic blood flow

Q16. For a low extraction drug, hepatic clearance is most influenced by:

• Intrinsic clearance and unbound fraction (fu)
• Hepatic blood flow only
• Urinary pH
• Dosage form

Correct Answer: Intrinsic clearance and unbound fraction (fu)

Q17. The area under the plasma concentration–time curve (AUC) is proportional to:

• Total systemic exposure to the drug
• Peak concentration only
• Volume of distribution only
• Absorption rate constant only

Correct Answer: Total systemic exposure to the drug

Q18. In noncompartmental analysis, AUC from time zero to infinity (AUC∞) equals:

• AUClast + Clast / ke
• AUMC / MRT
• Cmax × Tmax
• Vd / CL

Correct Answer: AUClast + Clast / ke

Q19. Fraction unbound (fu) affects clearance for low extraction drugs because:

• Only unbound drug is available for hepatic metabolism
• Protein-bound drug is cleared faster
• Fu determines absorption rate
• Fu equals bioavailability

Correct Answer: Only unbound drug is available for hepatic metabolism

Q20. Enterohepatic recirculation may cause which pharmacokinetic phenomenon?

• Secondary peaks in plasma concentration–time profile
• Immediate elimination without absorption
• Decreased Vd markedly
• Constant zero-order elimination

Correct Answer: Secondary peaks in plasma concentration–time profile

Q21. The formula for renal clearance using urine data is:

• CLr = (U × V) / P
• CLr = Dose / AUC
• CLr = Vd × ke
• CLr = Cmax / Tmax

Correct Answer: CLr = (U × V) / P

Q22. The fraction excreted unchanged in urine (fe) is defined as:

• Amount excreted in urine over dose administered
• CLr divided by Vd
• Bioavailability times clearance
• Peak concentration divided by AUC

Correct Answer: Amount excreted in urine over dose administered

Q23. Flip-flop kinetics occurs when:

• Absorption rate constant (Ka) is lower than elimination rate constant (ke)
• Ka is much higher than ke
• Drug follows zero-order elimination only
• Drug is administered intravenously

Correct Answer: Absorption rate constant (Ka) is lower than elimination rate constant (ke)

Q24. Which parameter best describes the time to reach peak plasma concentration after oral dosing?

• Tmax
• Cmax
• AUC
• Vd

Correct Answer: Tmax

Q25. Therapeutic drug monitoring is most useful for drugs with:

• Narrow therapeutic index and significant PK variability
• Very wide therapeutic index
• Undetectable plasma concentrations
• Only topical administration

Correct Answer: Narrow therapeutic index and significant PK variability

Q26. For oral dosing, apparent clearance (CL/F) is equal to:

• CL divided by bioavailability (F)
• CL multiplied by bioavailability
• Vd divided by AUC
• Ka divided by ke

Correct Answer: CL divided by bioavailability (F)

Q27. A drug exhibiting Michaelis–Menten kinetics will show:

• Nonlinear relationship between dose and AUC at high concentrations
• Constant half-life regardless of dose
• First-order elimination at all concentrations
• Bioavailability independent of dose

Correct Answer: Nonlinear relationship between dose and AUC at high concentrations

Q28. Which calculation gives the elimination rate constant (ke) from a linear semilog plot?

• Slope of ln(concentration) versus time with negative sign
• Intercept on y-axis
• Area under curve value
• Time to peak concentration

Correct Answer: Slope of ln(concentration) versus time with negative sign

Q29. AUC is most directly influenced by which pharmacokinetic parameter?

• Clearance
• Tmax
• Absorption rate constant only
• Protein binding only

Correct Answer: Clearance

Q30. The mean residence time (MRT) is defined in noncompartmental analysis as:

• AUMC / AUC
• AUC / CL
• Vd / ke
• Cmax / Tmax

Correct Answer: AUMC / AUC

Q31. Which factor decreases oral bioavailability of a drug?

• Extensive first-pass metabolism
• High aqueous solubility
• Rapid absorption with high Ka
• Administration by IV route

Correct Answer: Extensive first-pass metabolism

Q32. Protein binding changes will most directly affect which of the following for low extraction drugs?

• Hepatic clearance proportional to unbound fraction
• Hepatic blood flow
• Absorption from GI tract
• Renal filtration rate independent of fu

Correct Answer: Hepatic clearance proportional to unbound fraction

Q33. Bioequivalence study acceptance range for AUC and Cmax (90% CI) is commonly:

• 80–125%
• 50–150%
• 90–110%
• 60–140%

Correct Answer: 80–125%

Q34. If CL decreases while Vd remains constant, what happens to half-life?

• Half-life increases
• Half-life decreases
• Half-life remains unchanged
• Half-life becomes zero-order

Correct Answer: Half-life increases

Q35. In a two-compartment IV bolus model, the initial rapid decline represents:

• Distribution phase (alpha phase)
• Elimination phase only
• Absorption from gut
• Renal clearance plateau

Correct Answer: Distribution phase (alpha phase)

Q36. The absorption rate constant (Ka) primarily affects which PK parameter?

• Tmax and shape of absorption phase
• Clearance directly
• Volume of distribution
• Fraction unbound

Correct Answer: Tmax and shape of absorption phase

Q37. Which is the best description of clearance (CL)?

• Volume of plasma cleared of drug per unit time
• Fraction of drug absorbed
• Maximum rate of drug elimination
• Amount of drug in tissues

Correct Answer: Volume of plasma cleared of drug per unit time

Q38. For an IV bolus, initial concentration C0 is calculated as:

• C0 = Dose / Vd
• C0 = Dose × CL
• C0 = AUC / Dose
• C0 = Ka / ke

Correct Answer: C0 = Dose / Vd

Q39. AUC is directly proportional to dose for which type of kinetics?

• Linear (first-order) kinetics
• Michaelis–Menten saturated kinetics
• Zero-order elimination only
• Flip-flop kinetics only

Correct Answer: Linear (first-order) kinetics

Q40. Which clinical condition most likely reduces renal clearance of drugs eliminated by glomerular filtration?

• Reduced glomerular filtration rate (renal impairment)
• Increased hepatic blood flow
• Increased plasma protein binding without renal change
• High intestinal motility

Correct Answer: Reduced glomerular filtration rate (renal impairment)

Q41. When calculating maintenance dose from oral dosing, one should account for:

• Bioavailability (F)
• Only Vd
• Only Tmax
• Only protein binding

Correct Answer: Bioavailability (F)

Q42. The terminal slope in a log-linear plasma concentration plot after oral dosing usually represents:

• Elimination rate constant (ke) if Ka >> ke
• Absorption rate constant (Ka) always
• Volume of distribution directly
• Cmax value

Correct Answer: Elimination rate constant (ke) if Ka >> ke

Q43. A drug with a high Vd is less likely to be removed by hemodialysis because:

• Most of the drug resides in tissues, not plasma
• It is highly water soluble
• It has a very short half-life
• It is rapidly excreted unchanged in urine

Correct Answer: Most of the drug resides in tissues, not plasma

Q44. Which parameter would be most useful to assess changes in hepatic metabolism due to enzyme induction?

• Clearance (increase) and decreased AUC
• Increased Vd only
• Increased Tmax only
• Decreased fraction unbound only

Correct Answer: Clearance (increase) and decreased AUC

Q45. In a crossover bioequivalence study, each subject receives:

• Both test and reference formulations at different periods
• Only the test product
• Only the reference product
• Different doses of the same formulation only once

Correct Answer: Both test and reference formulations at different periods

Q46. Which statement about Cmax and AUC is correct?

• Cmax reflects rate and extent of absorption while AUC reflects extent of exposure
• Cmax equals AUC divided by CL
• AUC measures only peak concentration
• Cmax is independent of absorption rate

Correct Answer: Cmax reflects rate and extent of absorption while AUC reflects extent of exposure

Q47. If an orally administered drug has Fa (fraction absorbed), Fg (gut availability) and Fh (hepatic availability), overall F equals:

• F = Fa × Fg × Fh
• F = Fa + Fg + Fh
• F = Fa / (Fg × Fh)
• F = AUC × CL

Correct Answer: F = Fa × Fg × Fh

Q48. For a drug predominantly cleared by hepatic metabolism, which patient factor most affects dosing?

• Liver impairment and hepatic blood flow
• Height only
• Skin thickness
• GI transit time only

Correct Answer: Liver impairment and hepatic blood flow

Q49. Which method estimates the elimination rate constant from plasma concentration-time data?

• Linear regression of ln(concentration) versus time in the terminal phase
• Calculating Cmax/Tmax
• Multiplying dose by Vd
• Dividing AUC by dose

Correct Answer: Linear regression of ln(concentration) versus time in the terminal phase

Q50. Therapeutic index (TI) is defined as:

• The ratio of toxic dose to therapeutic dose indicating safety margin
• The bioavailability of a drug
• The half-life divided by clearance
• The volume of distribution per kg body weight

Correct Answer: The ratio of toxic dose to therapeutic dose indicating safety margin

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com