Immunosuppressants – mechanism and examples MCQs With Answer

Introduction:

Immunosuppressants are drugs that reduce immune system activity to prevent transplant rejection and treat autoimmune diseases. Understanding mechanisms—such as calcineurin inhibition (cyclosporine, tacrolimus), mTOR blockade (sirolimus), antimetabolite action (azathioprine, mycophenolate), alkylation (cyclophosphamide), and targeted biologics (rituximab, basiliximab)—is essential for B. Pharm students. Key concepts include pharmacokinetics, therapeutic drug monitoring, adverse effects (nephrotoxicity, myelosuppression, infections), drug interactions (CYP3A4 substrates), and monitoring strategies. This topic links mechanism to clinical use and safety. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which enzyme is directly inhibited by calcineurin inhibitors leading to reduced IL-2 transcription?

• Protein kinase A
• Calcineurin phosphatase
• DNA-dependent RNA polymerase
• Mammalian target of rapamycin (mTOR)

Correct Answer: Calcineurin phosphatase

Q2. Which immunosuppressant is primarily metabolized by CYP3A4 and often requires therapeutic drug monitoring due to a narrow therapeutic index?

• Mycophenolate mofetil
• Azathioprine
• Tacrolimus
• Methotrexate

Correct Answer: Tacrolimus

Q3. Mycophenolate mofetil exerts its immunosuppressive effect mainly by inhibiting which enzyme?

• Dihydrofolate reductase (DHFR)
• Inosine monophosphate dehydrogenase (IMPDH)
• Xanthine oxidase
• Thymidylate synthase

Correct Answer: Inosine monophosphate dehydrogenase (IMPDH)

Q4. Which adverse effect is most characteristically associated with calcineurin inhibitors like cyclosporine and tacrolimus?

• Pulmonary fibrosis
• Nephrotoxicity
• Ototoxicity
• Pancreatitis

Correct Answer: Nephrotoxicity

Q5. Sirolimus (rapamycin) primarily inhibits which intracellular pathway?

• JAK-STAT signaling
• mTOR signaling
• NF-κB activation
• Calcineurin pathway

Correct Answer: mTOR signaling

Q6. Azathioprine is a prodrug converted to which active metabolite that interferes with purine synthesis?

• 6-Mercaptopurine (6-MP)
• 5-Fluorouracil (5-FU)
• 6-Thioguanine nucleotide (6-TG)
• Allopurinol

Correct Answer: 6-Mercaptopurine (6-MP)

Q7. Which enzymatic polymorphism increases risk of azathioprine toxicity due to reduced metabolism of thiopurines?

• CYP2D6 polymorphism
• Thiopurine S-methyltransferase (TPMT) deficiency
• UDP-glucuronosyltransferase (UGT) deficiency
• Monoamine oxidase (MAO) deficiency

Correct Answer: Thiopurine S-methyltransferase (TPMT) deficiency

Q8. Which antibody targets CD20 on B cells and is used for autoimmune diseases and some transplant protocols?

• Basiliximab
• Rituximab
• Tocilizumab
• Infliximab

Correct Answer: Rituximab

Q9. Basiliximab acts by blocking which receptor on activated T cells?

• CD3 receptor
• CTLA-4
• IL-2 receptor alpha (CD25)
• TNF-α receptor

Correct Answer: IL-2 receptor alpha (CD25)

Q10. Which immunosuppressant commonly causes hyperlipidemia as a notable side effect?

• Cyclosporine
• Sirolimus
• Azathioprine
• Mycophenolate mofetil

Correct Answer: Sirolimus

Q11. Which drug class prevents lymphocyte proliferation by antagonizing folate metabolism?

• Antimetabolites like methotrexate
• Calcineurin inhibitors like tacrolimus
• mTOR inhibitors like sirolimus
• Monoclonal antibodies like rituximab

Correct Answer: Antimetabolites like methotrexate

Q12. Belatacept prevents T-cell activation by interfering with which co-stimulatory signal?

• CD28–CD80/86 interaction
• IL-2 binding to IL-2R
• TNF-α signaling
• TCR-MHC interaction

Correct Answer: CD28–CD80/86 interaction

Q13. Which of the following is a sphingosine-1-phosphate (S1P) receptor modulator that sequesters lymphocytes in lymph nodes?

• Fingolimod
• Tofacitinib
• Azathioprine
• Cyclosporine

Correct Answer: Fingolimod

Q14. Which adverse effect is most associated with alkylating agent cyclophosphamide?

• Hemorrhagic cystitis
• Cardiotoxicity
• Pulmonary fibrosis
• Peripheral neuropathy

Correct Answer: Hemorrhagic cystitis

Q15. Which monitoring parameter is most appropriate for tacrolimus dosing adjustment?

• Random plasma glucose
• Trough blood concentration (C0)
• Peak plasma concentration (Cmax) only
• Urinary creatinine

Correct Answer: Trough blood concentration (C0)

Q16. Tofacitinib, used in autoimmune disorders, acts by inhibiting which pathway?

• mTOR pathway
• JAK-STAT signaling
• Calcineurin phosphatase
• TNF-α production

Correct Answer: JAK-STAT signaling

Q17. Which pair of drugs are both calcineurin inhibitors?

• Cyclosporine and tacrolimus
• Sirolimus and everolimus
• Azathioprine and mycophenolate
• Rituximab and basiliximab

Correct Answer: Cyclosporine and tacrolimus

Q18. A major infectious risk in patients on long-term immunosuppression is reactivation of which latent infection?

• Varicella-zoster virus
• Human papillomavirus only
• Norovirus
• Rhinovirus

Correct Answer: Varicella-zoster virus

Q19. Which immunosuppressant is associated with gingival hyperplasia and hirsutism?

• Mycophenolate mofetil
• Cyclosporine
• Sirolimus
• Azathioprine

Correct Answer: Cyclosporine

Q20. Which drug’s interaction with allopurinol can increase risk of myelosuppression when co-administered?

• Methotrexate
• Azathioprine
• Cyclosporine
• Sirolimus

Correct Answer: Azathioprine

Q21. In organ transplantation, which regimen is commonly used as induction immunosuppression?

• Single-agent mycophenolate only
• High-dose corticosteroids with basiliximab or anti-thymocyte globulin
• Oral methotrexate alone
• Low-dose azathioprine only

Correct Answer: High-dose corticosteroids with basiliximab or anti-thymocyte globulin

Q22. Which biologic blocks TNF-α and is used in autoimmune diseases like rheumatoid arthritis?

• Infliximab
• Tocilizumab
• Basiliximab
• Belatacept

Correct Answer: Infliximab

Q23. Which immunosuppressive drug class carries a significant risk of progressive multifocal leukoencephalopathy (PML)?

• Anti-CD20 monoclonal antibodies (e.g., rituximab)
• Calcineurin inhibitors only
• mTOR inhibitors only
• Alkylating agents only

Correct Answer: Anti-CD20 monoclonal antibodies (e.g., rituximab)

Q24. Which statement about sirolimus is TRUE?

• It is highly nephrotoxic in therapeutic doses
• It inhibits T-cell proliferation by blocking mTOR
• It enhances IL-2 production
• It directly inhibits calcineurin

Correct Answer: It inhibits T-cell proliferation by blocking mTOR

Q25. Which monitoring is most important for patients on long-term azathioprine therapy?

• Complete blood count for myelosuppression
• ECG monthly
• Liver ultrasound monthly
• Fasting blood glucose weekly

Correct Answer: Complete blood count for myelosuppression

Q26. Which immunosuppressant is contraindicated with live vaccines due to risk of uncontrolled replication?

• Short course topical corticosteroids
• Any significant systemic immunosuppressant such as rituximab or high-dose corticosteroids
• Low-dose aspirin
• Vitamin D supplementation

Correct Answer: Any significant systemic immunosuppressant such as rituximab or high-dose corticosteroids

Q27. Everolimus is most closely related to which other immunosuppressant and shares a similar mechanism?

• Tacrolimus
• Sirolimus
• Azathioprine
• Mycophenolate mofetil

Correct Answer: Sirolimus

Q28. Which immunosuppressive agent requires attention to drug interactions with grapefruit juice due to CYP3A4 inhibition?

• Azathioprine
• Tacrolimus
• Mycophenolate mofetil
• Methotrexate

Correct Answer: Tacrolimus

Q29. Which is the primary therapeutic rationale for combining multiple immunosuppressants in transplant regimens?

• To increase cost and complexity
• To achieve synergistic immunosuppression at lower individual drug doses and reduce toxicity
• To target only B cells
• To avoid monitoring drug levels

Correct Answer: To achieve synergistic immunosuppression at lower individual drug doses and reduce toxicity

Q30. Which adverse effect is common to many systemic immunosuppressants and requires vigilant monitoring?

• Increased susceptibility to infections
• Excessive hair growth only
• Heightened wound healing
• Reduced risk of malignancy

Correct Answer: Increased susceptibility to infections

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