Cyclophosphamide MCQs With Answer

Cyclophosphamide MCQs With Answer is a focused set of practice questions designed for B. Pharm students to master cyclophosphamide pharmacology, mechanism, metabolism, clinical uses, dosing, and adverse effects. This collection emphasizes key concepts such as prodrug activation by hepatic cytochrome P450, formation of phosphoramide mustard and acrolein, hemorrhagic cystitis prevention with mesna and hydration, immunosuppressive and oncologic indications, monitoring parameters, drug interactions, and long-term safety concerns like gonadal toxicity and secondary malignancies. Questions range from basic definitions to clinical decision-making and monitoring strategies, helping students build deeper understanding and apply knowledge in practice. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary class of cyclophosphamide?

  • Oxazaphosphorine alkylating agent
  • Antimetabolite
  • Topoisomerase inhibitor
  • Monoclonal antibody

Correct Answer: Oxazaphosphorine alkylating agent

Q2. Cyclophosphamide is best described as which of the following before hepatic metabolism?

  • Active DNA cross-linker
  • Prodrug
  • Direct alkylator in plasma
  • Selective estrogen receptor modulator

Correct Answer: Prodrug

Q3. Which hepatic enzymes are primarily involved in activation of cyclophosphamide?

  • CYP2B6 and CYP3A4
  • CYP1A2 only
  • CYP2D6 and CYP2C19
  • Monoamine oxidase

Correct Answer: CYP2B6 and CYP3A4

Q4. What cytotoxic metabolite of cyclophosphamide is mainly responsible for DNA cross-linking?

  • Acrolein
  • Phosphoramide mustard
  • 4-hydroxycyclophosphamide only
  • Aldophosphamide hydrate

Correct Answer: Phosphoramide mustard

Q5. Which metabolite causes hemorrhagic cystitis and bladder toxicity?

  • Phosphoramide mustard
  • Acrolein
  • Carboxyphosphamide
  • 4-hydroxycyclophosphamide

Correct Answer: Acrolein

Q6. Which prophylactic agent is commonly co-administered to prevent cyclophosphamide-induced hemorrhagic cystitis?

  • Allopurinol
  • Mesna
  • Leucovorin
  • Probenecid

Correct Answer: Mesna

Q7. For which of the following autoimmune conditions is cyclophosphamide commonly used?

  • Type 1 diabetes
  • Systemic lupus erythematosus with organ involvement
  • Rheumatoid arthritis as first-line monotherapy
  • Graves’ disease

Correct Answer: Systemic lupus erythematosus with organ involvement

Q8. Which monitoring test is most important during cyclophosphamide therapy due to a major adverse effect?

  • Serum triglycerides
  • Complete blood count (CBC)
  • Pulmonary function only
  • Fasting glucose

Correct Answer: Complete blood count (CBC)

Q9. What is the mechanism by which cyclophosphamide alkylates DNA?

  • Inhibition of topoisomerase II
  • Formation of covalent bonds at N7 guanine causing interstrand cross-links
  • Incorporation as a false nucleotide
  • Selective methylation of promoter regions

Correct Answer: Formation of covalent bonds at N7 guanine causing interstrand cross-links

Q10. Which clinical formulation(s) is cyclophosphamide available in?

  • Oral only
  • Intravenous only
  • Oral and intravenous
  • Topical and intrathecal

Correct Answer: Oral and intravenous

Q11. Which of the following is a dose-limiting toxicity of cyclophosphamide?

  • Neurotoxicity manifesting as peripheral neuropathy
  • Myelosuppression leading to neutropenia
  • Ototoxicity
  • Severe hypoglycemia

Correct Answer: Myelosuppression leading to neutropenia

Q12. Which long-term adverse effect is associated with cyclophosphamide exposure?

  • Permanent hypothyroidism only
  • Gonadal toxicity and risk of infertility
  • Reversible cataracts in all patients
  • Chronic pancreatitis

Correct Answer: Gonadal toxicity and risk of infertility

Q13. Which malignancy risk is increased after cyclophosphamide therapy?

  • Bladder cancer
  • Basal cell carcinoma only
  • Prostate cancer exclusively
  • Renal cell carcinoma only

Correct Answer: Bladder cancer

Q14. In high-dose cyclophosphamide regimens, what supportive measure besides mesna reduces bladder toxicity?

  • Nephrectomy
  • Aggressive hydration and frequent voiding
  • Oral iron supplementation
  • Beta-blocker therapy

Correct Answer: Aggressive hydration and frequent voiding

Q15. Which statement about cyclophosphamide and pregnancy is correct?

  • Safe in all trimesters
  • Contraindicated due to teratogenicity
  • Only teratogenic if used with radiation
  • Safe after the first trimester

Correct Answer: Contraindicated due to teratogenicity

Q16. Which lab abnormality can cyclophosphamide induce via inappropriate ADH effects?

  • Hyperkalemia
  • Hyponatremia due to SIADH
  • Hypercalcemia
  • Metabolic alkalosis only

Correct Answer: Hyponatremia due to SIADH

Q17. Which drug interaction may reduce cyclophosphamide activation and efficacy?

  • CYP3A4 inducer like rifampicin
  • CYP3A4 inhibitor like ketoconazole
  • ACE inhibitors
  • Vitamin C supplementation

Correct Answer: CYP3A4 inhibitor like ketoconazole

Q18. How does mesna protect against acrolein-mediated toxicity?

  • By inhibiting hepatic CYP enzymes
  • By binding and detoxifying acrolein in urine
  • By increasing renal reabsorption of cyclophosphamide
  • By activating aldehyde dehydrogenase

Correct Answer: By binding and detoxifying acrolein in urine

Q19. A patient on cyclophosphamide should avoid which of the following vaccines?

  • Inactivated influenza vaccine
  • Live attenuated vaccines (e.g., varicella)
  • Pneumococcal polysaccharide vaccine
  • Hepatitis B recombinant vaccine

Correct Answer: Live attenuated vaccines (e.g., varicella)

Q20. Which pharmacokinetic property is important when switching from IV to oral cyclophosphamide?

  • Oral bioavailability is erratic but generally adequate for many regimens
  • Oral route completely bypasses hepatic activation
  • Oral administration causes no urinary metabolites
  • IV has no systemic toxicity compared to oral

Correct Answer: Oral bioavailability is erratic but generally adequate for many regimens

Q21. What immediate management step is appropriate for gross hematuria during cyclophosphamide therapy?

  • Stop cyclophosphamide and initiate mesna and hydration
  • Increase dose of cyclophosphamide
  • Administer IV calcium gluconate
  • Prescribe oral iron only

Correct Answer: Stop cyclophosphamide and initiate mesna and hydration

Q22. Which patient population requires special counseling about fertility preservation before cyclophosphamide?

  • Pediatric and reproductive-age patients
  • Elderly patients only
  • Patients with chronic hypertension only
  • Patients with controlled diabetes only

Correct Answer: Pediatric and reproductive-age patients

Q23. Cyclophosphamide’s cytotoxicity is greatest on which phase of the cell cycle?

  • M phase only
  • Cell cycle non-specific with activity in multiple phases
  • S phase exclusively
  • G0 phase only

Correct Answer: Cell cycle non-specific with activity in multiple phases

Q24. Which laboratory abnormality should be monitored due to the risk of hemorrhagic cystitis and renal effects?

  • Urinalysis for hematuria and proteinuria
  • Fasting lipid profile monthly
  • Serum amylase weekly
  • Thyroid function tests routinely

Correct Answer: Urinalysis for hematuria and proteinuria

Q25. Which clinical use of cyclophosphamide involves high-dose regimens as conditioning?

  • Treatment of mild asthma
  • Bone marrow/stem cell transplant conditioning
  • Topical therapy for skin infections
  • Chronic low-dose prophylaxis for migraines

Correct Answer: Bone marrow/stem cell transplant conditioning

Q26. Which adjustment is appropriate in severe renal impairment when using cyclophosphamide?

  • No adjustment needed; cyclophosphamide is unchanged by kidneys
  • Use caution and consider dose reduction because metabolites are renally excreted
  • Double the dose to overcome renal loss
  • Switch to oral tapering immediately

Correct Answer: Use caution and consider dose reduction because metabolites are renally excreted

Q27. Which adverse effect is more likely at very high doses of cyclophosphamide?

  • Cardiotoxicity such as heart failure or arrhythmia
  • Severe otitis externa
  • Isolated hyperglycemia without other effects
  • Immediate improvement in fertility

Correct Answer: Cardiotoxicity such as heart failure or arrhythmia

Q28. Which preventive counseling point is essential for patients receiving cyclophosphamide?

  • Avoid pregnancy and use effective contraception during and after therapy
  • No need for contraception as fertility is increased
  • Live vaccines provide protection during treatment without issue
  • High-dose vitamin E prevents all toxicities

Correct Answer: Avoid pregnancy and use effective contraception during and after therapy

Q29. Which blood disorder can cyclophosphamide rarely induce as a late complication?

  • Acute myeloid leukemia (secondary AML)
  • Essential thrombocythemia only
  • Polycythemia vera exclusively
  • Hemophilia A

Correct Answer: Acute myeloid leukemia (secondary AML)

Q30. Which statement best describes cyclophosphamide dosing strategy for autoimmune severe organ-threatening disease?

  • Single low oral dose monthly is always preferred
  • Pulse IV high-dose or daily oral regimens guided by severity, toxicity, and monitoring
  • Only topical application is effective for organ-threatening disease
  • No monitoring is required during long-term therapy

Correct Answer: Pulse IV high-dose or daily oral regimens guided by severity, toxicity, and monitoring

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