Renal and non-renal clearance concepts MCQs With Answer

Introduction

This quiz collection on renal and non-renal clearance concepts is designed for M.Pharm students preparing for Clinical Pharmacokinetics and Therapeutic Drug Monitoring. It focuses on core principles: definitions and calculations of clearance, physiological determinants (GFR, tubular secretion, reabsorption), hepatic and other non-renal elimination routes, impact of protein binding, extraction ratio concepts, and implications for dose adjustment in renal impairment or dialysis. Each question tests applied understanding required for therapeutic drug monitoring and rational dose modification. Answers are provided to reinforce learning and to help identify areas needing further study. Use these MCQs to consolidate knowledge and prepare for exams and clinical practice.

Q1. Which of the following best defines renal clearance of a drug?

• The volume of plasma completely cleared of the drug by the kidneys per unit time
• The total amount of drug excreted unchanged in urine per unit time
• The fraction of administered dose excreted unchanged in urine
• The concentration of drug in urine divided by plasma concentration

Correct Answer: The volume of plasma completely cleared of the drug by the kidneys per unit time

Q2. Which expression correctly represents renal clearance (CLr) based on urinary excretion measurements?

• CLr = (Urine concentration × Urine flow rate) / Plasma concentration
• CLr = Plasma concentration / (Urine concentration × Urine flow rate)
• CLr = Amount excreted unchanged / Bioavailable dose
• CLr = Fraction unbound × GFR

Correct Answer: CLr = (Urine concentration × Urine flow rate) / Plasma concentration

Q3. Renal clearance of a drug is the net result of which processes?

• Glomerular filtration plus tubular secretion minus tubular reabsorption
• Glomerular filtration minus tubular secretion plus tubular reabsorption
• Only glomerular filtration
• Only tubular secretion and reabsorption

Correct Answer: Glomerular filtration plus tubular secretion minus tubular reabsorption

Q4. Which clearance is considered the gold standard for measurement of true glomerular filtration rate?

• Inulin clearance
• Creatinine clearance
• Urea clearance
• Para-aminohippuric acid (PAH) clearance

Correct Answer: Inulin clearance

Q5. Para-aminohippuric acid (PAH) clearance is commonly used to estimate which renal parameter?

• Effective renal plasma flow (ERPF)
• Glomerular filtration rate (GFR)
• Renal clearance of creatinine
• Renal tubular reabsorption capacity

Correct Answer: Effective renal plasma flow (ERPF)

Q6. If a drug is highly protein-bound and eliminated only by glomerular filtration, what is the expected effect on renal clearance when plasma protein binding increases?

• Renal clearance decreases because less free drug is available for filtration
• Renal clearance increases because more drug is held in plasma
• No change in renal clearance because total plasma concentration does not change
• Renal clearance becomes equal to renal plasma flow

Correct Answer: Renal clearance decreases because less free drug is available for filtration

Q7. A drug has total clearance (CLtot) of 50 mL/min and renal clearance (CLr) of 20 mL/min. What is the non-renal clearance?

• 30 mL/min
• 70 mL/min
• 20 mL/min
• 50 mL/min

Correct Answer: 30 mL/min

Q8. According to the well-stirred (venous equilibrium) hepatic clearance model, which factors determine hepatic clearance?

• Hepatic blood flow, fraction unbound in blood, and intrinsic clearance
• Only hepatic blood flow
• Only fraction unbound in blood
• Only biliary excretion rate

Correct Answer: Hepatic blood flow, fraction unbound in blood, and intrinsic clearance

Q9. For a drug with a high hepatic extraction ratio (ER > 0.7), which statement is correct regarding its hepatic clearance?

• Hepatic clearance is approximately equal to hepatic blood flow and is flow-limited
• Hepatic clearance is independent of hepatic blood flow and depends only on protein binding
• Hepatic clearance is equal to intrinsic clearance and not influenced by blood flow
• Hepatic clearance is negligible and elimination is renal only

Correct Answer: Hepatic clearance is approximately equal to hepatic blood flow and is flow-limited

Q10. Fraction excreted unchanged in urine (fe) is defined as:

• The fraction of an administered dose excreted unchanged in the urine
• Urinary clearance divided by renal plasma flow
• Total body clearance divided by renal clearance
• The ratio of urine to plasma drug concentrations at steady state

Correct Answer: The fraction of an administered dose excreted unchanged in the urine

Q11. Which set of drug properties favors efficient removal by hemodialysis?

• Low molecular weight, low protein binding, small apparent volume of distribution, water solubility
• High molecular weight, high protein binding, large volume of distribution, lipophilic
• High tissue binding and high lipophilicity
• Extensive hepatic metabolism and biliary excretion

Correct Answer: Low molecular weight, low protein binding, small apparent volume of distribution, water solubility

Q12. Which of the following is the major non-renal route responsible for elimination of most drugs?

• Hepatic metabolism (biotransformation)
• Sweat excretion
• Tear fluid excretion
• Salivary secretion

Correct Answer: Hepatic metabolism (biotransformation)

Q13. In patients with decreased renal function for a drug primarily eliminated unchanged by the kidney, which dosing strategy is appropriate to maintain similar drug exposure?

• Reduce dose or increase dosing interval to match reduced clearance
• Increase dose to compensate for decreased excretion
• No change in dose or interval is required
• Stop the drug entirely regardless of severity

Correct Answer: Reduce dose or increase dosing interval to match reduced clearance

Q14. Which equation correctly expresses the relationship between total body clearance and individual organ clearances?

• CLtotal = CLrenal + CLhepatic + CLother
• CLtotal = CLrenal × CLhepatic
• CLtotal = CLrenal – CLhepatic
• CLtotal = (CLrenal + CLhepatic) / 2

Correct Answer: CLtotal = CLrenal + CLhepatic + CLother

Q15. What is the expected effect of enzyme induction on non-renal clearance of a drug primarily eliminated by hepatic metabolism?

• Non-renal clearance increases and elimination half-life decreases
• Non-renal clearance decreases and half-life increases
• No change in clearance or half-life
• Renal clearance increases to compensate

Correct Answer: Non-renal clearance increases and elimination half-life decreases

Q16. If a drug’s renal clearance exceeds the glomerular filtration rate, which renal process most likely contributes?

• Active tubular secretion
• Passive tubular reabsorption
• Protein binding within plasma
• Renal blood flow limitation

Correct Answer: Active tubular secretion

Q17. Which units are appropriate for expressing clearance in clinical pharmacokinetics?

• Volume per unit time (e.g., mL/min or L/hr)
• Mass per unit time (e.g., mg/hr)
• Concentration (e.g., mg/L)
• Percentage of dose per hour

Correct Answer: Volume per unit time (e.g., mL/min or L/hr)

Q18. Unbound clearance (CLu) is defined as which of the following?

• CLu = CL / fraction unbound (fu)
• CLu = CL × fraction unbound (fu)
• CLu = CL × fraction bound (1 − fu)
• CLu is independent of fraction unbound

Correct Answer: CLu = CL / fraction unbound (fu)

Q19. Which drug properties favor biliary excretion as a significant non-renal elimination pathway?

• High molecular weight (typically >300–500 Da) and polar (conjugated) metabolites
• Very low molecular weight and extreme lipophilicity
• Only renal filtration without metabolism
• High volatility and pulmonary elimination

Correct Answer: High molecular weight (typically >300–500 Da) and polar (conjugated) metabolites

Q20. Which statement correctly describes drugs with low hepatic extraction ratio (ER ≤ 0.3)?

• Hepatic clearance is sensitive to changes in fraction unbound and intrinsic clearance, less sensitive to hepatic blood flow
• Hepatic clearance is primarily flow-limited and independent of protein binding
• Hepatic clearance is negligible and drug elimination is entirely renal
• Hepatic clearance increases linearly with increasing hepatic blood flow regardless of metabolism

Correct Answer: Hepatic clearance is sensitive to changes in fraction unbound and intrinsic clearance, less sensitive to hepatic blood flow

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