Azathioprine MCQs With Answer

Azathioprine MCQs With Answer

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Azathioprine MCQs With Answer

Azathioprine is a thiopurine immunosuppressant used in transplantation and autoimmune diseases. B.Pharm students should understand its pharmacology: it is a prodrug of 6-mercaptopurine that inhibits de novo purine synthesis, reduces lymphocyte proliferation, and requires metabolism by TPMT and xanthine oxidase. Key topics include dosing principles, monitoring (CBC, LFTs), adverse effects (myelosuppression, hepatotoxicity, pancreatitis), important drug interactions (allopurinol), and genetic testing implications. This set of focused, clinically relevant MCQs reinforces mechanism of action, pharmacokinetics, safety monitoring, and therapeutic use in a pharmacy curriculum. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which enzyme converts azathioprine into its active metabolite 6-mercaptopurine?

  • Thiopurine methyltransferase (TPMT)
  • Xanthine oxidase
  • Glutathione S-transferase
  • Non-enzymatic cleavage to 6-mercaptopurine

Correct Answer: Non-enzymatic cleavage to 6-mercaptopurine

Q2. What is the primary immunosuppressive mechanism of azathioprine?

  • Inhibition of calcineurin
  • Alkylation of DNA leading to cross-links
  • Antagonism of TNF-alpha receptors
  • Inhibition of de novo purine synthesis reducing lymphocyte proliferation

Correct Answer: Inhibition of de novo purine synthesis reducing lymphocyte proliferation

Q3. Which genetic test is most relevant before starting azathioprine to predict risk of myelosuppression?

  • CYP2C19 genotyping
  • HLA-B*57:01 testing
  • TPMT (thiopurine methyltransferase) activity/genotyping
  • BRCA1/BRCA2 mutation screening

Correct Answer: TPMT (thiopurine methyltransferase) activity/genotyping

Q4. Co-administration of allopurinol with azathioprine most likely causes:

  • Reduced azathioprine efficacy due to increased clearance
  • Increased risk of severe myelosuppression
  • Enhanced hepatic metabolism preventing toxicity
  • No clinically relevant interaction

Correct Answer: Increased risk of severe myelosuppression

Q5. Which monitoring parameter is essential during azathioprine therapy?

  • Fasting blood glucose monthly
  • Complete blood count (CBC) regularly
  • Serum theophylline levels
  • Serum amylase only once at start

Correct Answer: Complete blood count (CBC) regularly

Q6. A common hematologic adverse effect of azathioprine is:

  • Leukocytosis
  • Hemolytic anemia due to G6PD deficiency
  • Myelosuppression causing leukopenia and thrombocytopenia
  • Polycythemia

Correct Answer: Myelosuppression causing leukopenia and thrombocytopenia

Q7. Azathioprine is contraindicated or used with caution in pregnancy because:

  • It is a known teratogen causing neural tube defects
  • It causes permanent infertility in both sexes
  • It can cross the placenta and carry potential fetal risk but may be used if benefits outweigh risks
  • It increases uterine contractions leading to preterm labor

Correct Answer: It can cross the placenta and carry potential fetal risk but may be used if benefits outweigh risks

Q8. Which adverse effect is characteristic but less common with azathioprine?

  • Pancreatitis
  • Severe hypertension
  • Bronchospasm
  • Hyperglycemia

Correct Answer: Pancreatitis

Q9. Which enzyme metabolizes 6-mercaptopurine to inactive thiouric acid?

  • CYP3A4
  • Xanthine oxidase
  • UDP-glucuronosyltransferase
  • Monoamine oxidase

Correct Answer: Xanthine oxidase

Q10. TPMT deficiency leads to which of the following when treated with standard azathioprine doses?

  • Increased hepatic clearance and therapeutic failure
  • Severe myelosuppression due to accumulation of active thioguanine nucleotides
  • No effect on drug response
  • Enhanced renal excretion of metabolites

Correct Answer: Severe myelosuppression due to accumulation of active thioguanine nucleotides

Q11. Which clinical use of azathioprine is most common?

  • Treatment of acute bacterial infections
  • Maintenance immunosuppression in organ transplantation and autoimmune diseases
  • First-line therapy for rheumatoid arthritis as monotherapy in all cases
  • Emergency treatment for anaphylaxis

Correct Answer: Maintenance immunosuppression in organ transplantation and autoimmune diseases

Q12. The onset of immunosuppressive action of azathioprine is typically:

  • Immediate within minutes
  • Hours after a single dose
  • Several weeks to months
  • Never—it’s solely a diagnostic agent

Correct Answer: Several weeks to months

Q13. Which of the following is a serious hepatic adverse effect associated with azathioprine?

  • Cholestatic jaundice and hepatotoxicity
  • Hepatic fibrosis only after decades
  • Immediate fulminant hepatic failure in all patients
  • No known liver effects

Correct Answer: Cholestatic jaundice and hepatotoxicity

Q14. In patients on azathioprine who develop fever and sore throat, the pharmacist should advise:

  • Continue drug and take over-the-counter cold remedies
  • Immediately stop azathioprine and seek urgent medical review with CBC
  • Reduce dose by half and recheck in 6 months
  • Switch to allopurinol to prevent infection

Correct Answer: Immediately stop azathioprine and seek urgent medical review with CBC

Q15. Which statement about azathioprine pharmacokinetics is true?

  • Azathioprine is primarily excreted unchanged by the kidney
  • It is a prodrug rapidly converted to 6-mercaptopurine after absorption
  • It has a very long half-life of several weeks
  • It is not absorbed orally and requires IV administration

Correct Answer: It is a prodrug rapidly converted to 6-mercaptopurine after absorption

Q16. Which drug interaction increases active thioguanine nucleotide levels when given with azathioprine?

  • Allopurinol
  • Rifampicin
  • Phenytoin
  • Metformin

Correct Answer: Allopurinol

Q17. Which laboratory test specifically helps detect azathioprine-induced hepatotoxicity?

  • Serum creatinine
  • ALT and AST levels
  • Serum potassium
  • Pulmonary function test

Correct Answer: ALT and AST levels

Q18. Comparing azathioprine and 6-mercaptopurine, which is correct?

  • Azathioprine is the active metabolite of 6-mercaptopurine
  • 6-mercaptopurine is the prodrug of azathioprine
  • Azathioprine is a prodrug that converts to 6-mercaptopurine in vivo
  • They are unrelated drugs with different mechanisms

Correct Answer: Azathioprine is a prodrug that converts to 6-mercaptopurine in vivo

Q19. Which patient factor increases the risk of azathioprine toxicity?

  • High TPMT activity
  • Concomitant use of xanthine oxidase inhibitors like allopurinol
  • Young age alone without other factors
  • Low body weight only

Correct Answer: Concomitant use of xanthine oxidase inhibitors like allopurinol

Q20. Azathioprine dosing in adults for autoimmune disease is typically adjusted based on:

  • Blood pressure readings
  • Body surface area and tolerability with CBC monitoring
  • Serum azathioprine concentration assay
  • Random blood glucose

Correct Answer: Body surface area and tolerability with CBC monitoring

Q21. Which infection risk is increased with azathioprine therapy?

  • Only bacterial skin infections, no systemic infections
  • Opportunistic infections including viral and fungal pathogens
  • Azathioprine has antimicrobial properties, reducing infections
  • It specifically prevents tuberculosis

Correct Answer: Opportunistic infections including viral and fungal pathogens

Q22. What counseling point about vaccinations should be given to patients starting azathioprine?

  • Live vaccines should be avoided or given with caution during immunosuppression
  • All vaccines are safe and should be given without timing consideration
  • Vaccination is contraindicated permanently
  • Only oral vaccines are affected

Correct Answer: Live vaccines should be avoided or given with caution during immunosuppression

Q23. Long-term azathioprine therapy has been associated with which malignancy risk increase?

  • Decreased risk of all cancers
  • No change in malignancy risk
  • Increased risk of lymphoma and skin cancers
  • Exclusive increase in prostate cancer only

Correct Answer: Increased risk of lymphoma and skin cancers

Q24. How does TPMT high activity affect azathioprine therapy?

  • Increases risk of myelosuppression
  • Leads to faster inactivation and potentially reduced efficacy
  • Causes accumulation of active metabolites
  • Has no clinical significance

Correct Answer: Leads to faster inactivation and potentially reduced efficacy

Q25. Which adverse effect may present early after starting azathioprine?

  • Chronic kidney disease after years
  • Acute pancreatitis within weeks
  • Delayed skin cancer decades later only
  • Immediate chronic liver cirrhosis

Correct Answer: Acute pancreatitis within weeks

Q26. When converting a patient from azathioprine to 6-mercaptopurine, pharmacists should consider:

  • No dose adjustment is ever needed
  • Equivalent dosing may require adjustment due to different bioavailability and tolerability
  • They cannot be interchanged under any circumstances
  • 6-mercaptopurine is only used topically

Correct Answer: Equivalent dosing may require adjustment due to different bioavailability and tolerability

Q27. Which statement about azathioprine and renal impairment is true?

  • Azathioprine is contraindicated in any renal impairment
  • No dose adjustments are needed because metabolites are not renally cleared
  • Caution is required; monitor for toxicity though primary metabolism is hepatic and enzymatic
  • Renal impairment enhances TPMT activity

Correct Answer: Caution is required; monitor for toxicity though primary metabolism is hepatic and enzymatic

Q28. Which best describes therapeutic drug monitoring for azathioprine?

  • Routine measurement of serum azathioprine levels is standard practice
  • Monitoring thioguanine nucleotide levels and TPMT activity can guide dosing in select cases
  • Only urine tests are useful
  • No monitoring is necessary for safety

Correct Answer: Monitoring thioguanine nucleotide levels and TPMT activity can guide dosing in select cases

Q29. A patient on azathioprine develops severe neutropenia. The immediate pharmacist recommendation is:

  • Increase the dose to overcome resistance
  • Withhold azathioprine and notify prescriber urgently
  • Start erythropoietin therapy immediately
  • Advise high-protein diet and continue therapy

Correct Answer: Withhold azathioprine and notify prescriber urgently

Q30. Which statement about azathioprine’s effect on lymphocytes is correct?

  • It selectively increases T-lymphocyte proliferation
  • It causes apoptosis and reduces proliferation of both B and T lymphocytes by nucleotide depletion
  • It enhances antibody production by B cells
  • It only affects neutrophils and has no lymphocyte effect

Correct Answer: It causes apoptosis and reduces proliferation of both B and T lymphocytes by nucleotide depletion

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