Busulfan MCQs With Answer is a focused study tool for B. Pharm students covering busulfan’s pharmacology, clinical uses, dosing, pharmacokinetics, adverse effects, drug interactions, and therapeutic monitoring. These questions emphasize its mechanism as an alkylating, myeloablative agent used in conditioning regimens and certain hematologic malignancies, along with formulation differences (oral vs IV) and major toxicities such as pulmonary fibrosis and hepatic veno-occlusive disease. Expect items on metabolism by glutathione S‑transferases, seizure risk and prophylaxis, dose adjustments, and the rationale for AUC‑guided dosing. Clear, clinically relevant MCQs target knowledge needed for pharmacy practice and exams. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary pharmacological mechanism of action of busulfan?
- Inhibition of topoisomerase II
- Alkylation of DNA causing cross‑links
- Antimetabolite inhibition of thymidylate synthase
- Selective inhibition of tyrosine kinases
Correct Answer: Alkylation of DNA causing cross‑links
Q2. Which clinical indication historically involved busulfan therapy?
- Acute bacterial meningitis
- Chronic myeloid leukemia conditioning and therapy
- Type 1 diabetes mellitus
- Hyperlipidemia management
Correct Answer: Chronic myeloid leukemia conditioning and therapy
Q3. Which formulation of busulfan offers more predictable systemic exposure?
- Oral tablets
- Topical gel
- Intravenous infusion
- Inhalation powder
Correct Answer: Intravenous infusion
Q4. Which enzyme family primarily metabolizes busulfan?
- CYP3A4 (cytochrome P450)
- Monoamine oxidases
- Glutathione S‑transferases (GSTA1 predominately)
- Alcohol dehydrogenase
Correct Answer: Glutathione S‑transferases (GSTA1 predominately)
Q5. What is a hallmark pulmonary adverse effect associated with busulfan?
- Bronchial asthma exacerbation
- Pulmonary fibrosis (“busulfan lung”)
- Pulmonary embolism due to hypercoagulability
- Alveolar hemorrhage caused by platelet activation
Correct Answer: Pulmonary fibrosis (“busulfan lung”)
Q6. Why is therapeutic drug monitoring (TDM) often used with busulfan?
- To measure plasma protein binding variability
- To adjust dose based on target exposure (AUC) and reduce toxicity
- Because busulfan has a very short half‑life needing continuous monitoring
- To prevent bacterial contamination during administration
Correct Answer: To adjust dose based on target exposure (AUC) and reduce toxicity
Q7. Which adverse hepatic condition is associated with high‑dose busulfan in conditioning regimens?
- Acute fatty liver of pregnancy
- Hepatic veno‑occlusive disease (sinusoidal obstruction syndrome)
- Biliary atresia
- Autoimmune hepatitis
Correct Answer: Hepatic veno‑occlusive disease (sinusoidal obstruction syndrome)
Q8. Which anticonvulsant is commonly recommended for seizure prophylaxis during busulfan therapy due to minimal enzyme induction?
- Phenytoin
- Carbamazepine
- Levetiracetam
- Phenobarbital
Correct Answer: Levetiracetam
Q9. Which statement about oral busulfan is true?
- Oral bioavailability is consistently 100%
- Oral dosing leads to highly variable systemic exposure
- Oral busulfan is not absorbed at all
- Oral busulfan is preferred when rapid predictable exposure is required
Correct Answer: Oral dosing leads to highly variable systemic exposure
Q10. Which patient monitoring parameter is most critical during high‑dose busulfan conditioning?
- Blood glucose every hour
- Serial measurement of busulfan plasma concentrations for AUC estimation
- Daily chest X‑ray only
- Serum cholesterol weekly
Correct Answer: Serial measurement of busulfan plasma concentrations for AUC estimation
Q11. Which group is at higher risk for severe busulfan toxicity and often requires dose adjustments?
- Young adult males with normal liver function
- Patients with impaired hepatic function
- Patients with controlled hypertension only
- Individuals with isolated kidney stones
Correct Answer: Patients with impaired hepatic function
Q12. What is the main rationale for combining busulfan with cyclophosphamide in conditioning regimens?
- To reduce mucositis risk
- Synergistic myeloablation and enhanced antineoplastic effect
- To prevent infection during neutropenia
- To minimize alopecia
Correct Answer: Synergistic myeloablation and enhanced antineoplastic effect
Q13. Which organ system toxicity is least commonly associated with busulfan?
- Hematologic suppression
- Pulmonary fibrosis
- Cardiac arrhythmias as a primary effect
- Hepatic veno‑occlusive disease
Correct Answer: Cardiac arrhythmias as a primary effect
Q14. Which population requires extreme caution or avoidance of busulfan due to teratogenicity?
- Pregnant women
- Postmenopausal women
- Adolescent males after puberty
- Men with controlled hypothyroidism
Correct Answer: Pregnant women
Q15. Which laboratory finding reflects the expected pharmacodynamic effect of myeloablation by busulfan?
- Progressive leukocytosis
- Pancytopenia with profound neutropenia
- Isolated hyperkalemia
- Elevated serum albumin
Correct Answer: Pancytopenia with profound neutropenia
Q16. Which clinical sign should prompt evaluation for busulfan‑related pulmonary toxicity?
- New onset productive cough with high fever only
- Progressive dyspnea and nonproductive cough with interstitial changes on imaging
- Isolated rhinorrhea without hypoxia
- Asymptomatic mild wheeze that resolves spontaneously
Correct Answer: Progressive dyspnea and nonproductive cough with interstitial changes on imaging
Q17. Which statement about drug interactions with busulfan is correct?
- Strong enzyme inducers may decrease busulfan exposure
- All antifungal agents are safe and have no interaction
- Antibiotics universally increase busulfan clearance
- Co‑administration of acetaminophen doubles busulfan activity
Correct Answer: Strong enzyme inducers may decrease busulfan exposure
Q18. Which supportive care measure reduces seizure risk during busulfan therapy?
- High‑dose corticosteroids only
- Prophylactic anticonvulsant administration during the peritransplant period
- Avoiding all analgesics
- Routine daily EEG monitoring for all patients
Correct Answer: Prophylactic anticonvulsant administration during the peritransplant period
Q19. Which pharmacokinetic property of busulfan is clinically relevant for dosing strategies?
- Complete renal excretion unchanged
- High interpatient variability in clearance requiring individualized dosing
- Zero variability between oral and IV routes
- Extremely long half‑life making single dosing sufficient
Correct Answer: High interpatient variability in clearance requiring individualized dosing
Q20. Which laboratory assay is used to guide busulfan dosing by assessing systemic exposure?
- Serum creatinine clearance only
- Plasma busulfan concentration and AUC calculation
- Urine dipstick protein measurement
- Serum amylase level
Correct Answer: Plasma busulfan concentration and AUC calculation
Q21. Which adverse effect is an expected short‑term consequence of myeloablative busulfan therapy?
- Polycythemia
- Mucositis and profound neutropenia
- Improved wound healing
- Chronic hypercalcemia
Correct Answer: Mucositis and profound neutropenia
Q22. Which factor can increase busulfan exposure leading to greater toxicity?
- Co‑administration of enzyme inducers
- Impaired hepatic glutathione conjugation capacity
- Increased oral clearance due to diarrhea
- Concurrent use of activated charcoal
Correct Answer: Impaired hepatic glutathione conjugation capacity
Q23. What is the clinical purpose of busulfan in hematopoietic stem cell transplantation?
- To stimulate platelet production post‑transplant
- To provide myeloablation and immunosuppression prior to grafting
- To treat immediate graft‑versus‑host disease
- To prevent viral reactivation
Correct Answer: To provide myeloablation and immunosuppression prior to grafting
Q24. Which monitoring is essential after high‑dose busulfan administration during transplant conditioning?
- Frequent measurement of bone mineral density
- Daily complete blood counts and frequent infection surveillance
- Weekly lipid profile checks
- Monthly liver ultrasound only
Correct Answer: Daily complete blood counts and frequent infection surveillance
Q25. Which statement about busulfan dosing units is correct?
- Doses are commonly expressed in mg/kg body weight
- Doses are always fixed irrespective of patient size
- Busulfan is dosed in IU units like biologics
- Dosing is based solely on age in years
Correct Answer: Doses are commonly expressed in mg/kg body weight
Q26. Which prophylactic strategy is used to reduce hepatic veno‑occlusive disease risk with busulfan regimens?
- High‑dose vitamin K started prior to therapy
- Use of conditioning regimen adjustments and supportive hepatic care
- Routine daily aspirin during conditioning
- Immediate post‑transplant iron chelation
Correct Answer: Use of conditioning regimen adjustments and supportive hepatic care
Q27. Which adverse effect is most responsible for long‑term morbidity after busulfan therapy?
- Transient nausea only
- Chronic pulmonary fibrosis and restrictive lung disease
- Temporary alopecia that resolves in weeks
- Short lived taste disturbance
Correct Answer: Chronic pulmonary fibrosis and restrictive lung disease
Q28. Which statement about busulfan and fertility is true?
- Busulfan has no effect on gonadal function
- Busulfan can cause gonadal failure and infertility in both sexes
- Busulfan enhances fertility after therapy
- Fertility effects are limited to transient erectile dysfunction only
Correct Answer: Busulfan can cause gonadal failure and infertility in both sexes
Q29. Which dosing approach improves safety when starting busulfan in adults with variable clearance?
- Empiric maximal dosing without monitoring
- Initial dosing followed by early plasma concentration sampling and dose adjustment
- Weekly dosing with no initial monitoring
- Switching randomly between IV and oral routes daily
Correct Answer: Initial dosing followed by early plasma concentration sampling and dose adjustment
Q30. Which item best describes the role of busulfan in modern hematology practice?
- Rarely used and only for outpatient dermatologic conditions
- Important myeloablative agent for conditioning before hematopoietic stem cell transplant
- Primary therapy for acute coronary syndromes
- Standard oral antibiotic for community infections
Correct Answer: Important myeloablative agent for conditioning before hematopoietic stem cell transplant
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