TDM examples: Cyclosporine (transplantation) MCQs With Answer

Introduction

This blog focuses on therapeutic drug monitoring (TDM) of cyclosporine in transplantation — a critical area for M.Pharm students preparing for advanced clinical pharmacokinetics. Cyclosporine has a narrow therapeutic index, marked inter- and intra-patient pharmacokinetic variability, and clinically important interactions that influence efficacy and toxicity. Understanding sampling strategies (C0 vs C2), appropriate biological matrices and assay selection, dose adjustments in hepatic impairment, and common drug interactions is essential for safe transplant management. The following 20 MCQs are designed to deepen conceptual and practical knowledge, reinforce monitoring principles, and prepare you for real-world TDM decision-making in transplant pharmacotherapy.

Q1. Which is the primary rationale for performing therapeutic drug monitoring (TDM) for cyclosporine in transplant patients?

• To reduce pill burden by spacing doses further apart
• Because cyclosporine has a narrow therapeutic index and large pharmacokinetic variability
• To routinely detect immune system markers
• To monitor renal function exclusively

Correct Answer: Because cyclosporine has a narrow therapeutic index and large pharmacokinetic variability

Q2. What is the recommended biological sample type for routine cyclosporine concentration measurement?

• Serum collected in plain tube
• Plasma collected in heparin tube
• Whole blood collected in EDTA tube
• Urine 24-hour collection

Correct Answer: Whole blood collected in EDTA tube

Q3. Which hepatic enzyme is primarily responsible for the metabolism of cyclosporine?

• CYP2D6
• CYP1A2
• CYP3A4
• UDP-glucuronosyltransferase

Correct Answer: CYP3A4

Q4. Which transporter significantly affects cyclosporine absorption and disposition?

• OATP1B1
• P-glycoprotein (P-gp / ABCB1)
• GLUT2
• ENaC

Correct Answer: P-glycoprotein (P-gp / ABCB1)

Q5. What is the most clinically significant adverse effect that TDM aims to reduce for cyclosporine?

• Ototoxicity
• Nephrotoxicity
• Bone marrow suppression
• Hypoglycemia

Correct Answer: Nephrotoxicity

Q6. Which post-dose sampling time (for microemulsion formulations) most closely correlates with cyclosporine AUC and is often recommended for better exposure assessment?

• Trough (C0, immediately before dose)
• 1-hour post-dose (C1)
• 2-hour post-dose (C2)
• 4-hour post-dose (C4)

Correct Answer: 2-hour post-dose (C2)

Q7. Which analytical method provides the highest specificity for measuring cyclosporine concentrations and minimizing metabolite cross-reactivity?

• Radioimmunoassay (RIA)
• Enzyme-linked immunosorbent assay (ELISA)
• High-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS)
• Colorimetric assay

Correct Answer: High-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS)

Q8. Co-administration of ketoconazole with cyclosporine is expected to cause which of the following effects on cyclosporine concentrations?

• Decrease cyclosporine levels by inducing metabolism
• No significant change in cyclosporine levels
• Increase cyclosporine levels by inhibiting CYP3A4
• Increase renal clearance of cyclosporine without changing blood levels

Correct Answer: Increase cyclosporine levels by inhibiting CYP3A4

Q9. What effect does grapefruit juice have on oral cyclosporine exposure?

• Decreases absorption by binding cyclosporine in the gut
• No effect on cyclosporine exposure
• Increases exposure by inhibiting intestinal CYP3A4
• Enhances renal elimination

Correct Answer: Increases exposure by inhibiting intestinal CYP3A4

Q10. When converting an inpatient IV cyclosporine infusion to oral dosing, the oral dose is typically adjusted how relative to the IV dose?

• Oral dose is approximately one-third of the IV dose
• Oral dose is approximately equal to the IV dose
• Oral dose is approximately three times the IV dose
• Oral dose should be ten times the IV dose

Correct Answer: Oral dose is approximately three times the IV dose

Q11. Early after transplantation, how frequently is cyclosporine concentration monitoring typically performed to guide dose adjustments?

• Every 6 months
• Daily or several times per week initially
• Once a year
• Only when toxicity appears

Correct Answer: Daily or several times per week initially

Q12. Which metabolic adverse effect is commonly associated with chronic cyclosporine therapy?

• Hypolipidemia
• Hyperlipidemia
• Hypokalemia
• Weight loss

Correct Answer: Hyperlipidemia

Q13. How would you best describe the elimination half-life of cyclosporine in clinical practice?

• Extremely short and fixed at 1 hour
• Highly variable between patients, commonly in the range of roughly 8–24 hours
• Always longer than 100 hours
• Constant at 48 hours in all patients

Correct Answer: Highly variable between patients, commonly in the range of roughly 8–24 hours

Q14. Which drug would most likely decrease cyclosporine blood concentrations by inducing its metabolism?

• Rifampicin (rifampin)
• Clarithromycin
• Ketoconazole
• Fluconazole

Correct Answer: Rifampicin (rifampin)

Q15. One limitation of using trough concentration (C0) for cyclosporine monitoring is:

• C0 values are perfectly predictive of AUC in all patients
• C0 correlates poorly with total exposure (AUC) compared with C2 in many patients
• C0 sampling is impractical because it must be taken 6 hours post-dose
• C0 measurements eliminate the need for clinical assessment

Correct Answer: C0 correlates poorly with total exposure (AUC) compared with C2 in many patients

Q16. Which formulation or assay issue can lead to overestimation of cyclosporine concentration when using some immunoassays?

• High specificity for parent drug
• Cross-reactivity with cyclosporine metabolites
• Complete separation of metabolites before assay
• No matrix effects in whole blood

Correct Answer: Cross-reactivity with cyclosporine metabolites

Q17. In a patient with moderate hepatic impairment, how is cyclosporine pharmacokinetics most likely affected?

• Hepatic impairment increases metabolic clearance leading to lower levels
• Hepatic impairment decreases clearance and increases exposure
• Hepatic impairment has no effect on cyclosporine levels
• Hepatic impairment only affects renal elimination of cyclosporine

Correct Answer: Hepatic impairment decreases clearance and increases exposure

Q18. How should therapeutic monitoring frequency be adjusted for pediatric transplant patients compared with adults?

• Pediatrics require less frequent monitoring because dosing is simpler
• Pediatrics require more frequent monitoring due to higher clearance variability
• No monitoring is necessary in pediatric patients
• Monitoring frequency is identical and never changed

Correct Answer: Pediatrics require more frequent monitoring due to higher clearance variability

Q19. Acute onset of severe diarrhea in a patient on oral cyclosporine is most likely to cause which immediate effect on blood concentrations?

• Increased oral absorption and supratherapeutic concentrations
• No effect on cyclosporine absorption
• Decreased oral absorption leading to lower blood concentrations
• Enhanced renal clearance without changing absorption

Correct Answer: Decreased oral absorption leading to lower blood concentrations

Q20. What is the fundamental therapeutic goal of TDM for cyclosporine in transplantation?

• To ensure drug levels are always below assay detection limits
• To maximize graft immunosuppression while minimizing drug-related toxicity
• To replace clinical judgment with laboratory values alone
• To maintain a single fixed dose for all patients

Correct Answer: To maximize graft immunosuppression while minimizing drug-related toxicity

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