Floxuridine MCQs With Answer

Floxuridine MCQs With Answer

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Floxuridine MCQs With Answer

Floxuridine (FUdR) is a fluoropyrimidine antimetabolite used mainly for regional treatment of colorectal liver metastases. B. Pharm students should understand its mechanism—conversion to FdUMP and inhibition of thymidylate synthase—pharmacokinetics with high hepatic extraction, clinical applications, dosing strategies (particularly hepatic arterial infusion), and key toxicities such as myelosuppression, mucositis, and hepatic injury. This set goes deeper into metabolism, drug interactions, monitoring, resistance mechanisms, and practical handling considerations to prepare you for exams and clinical pharmacy practice. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary mechanism of action of floxuridine?

  • Inhibition of topoisomerase II leading to DNA strand breaks
  • Inhibition of microtubule polymerization during mitosis
  • Inhibition of thymidylate synthase leading to decreased dTMP and impaired DNA synthesis
  • Alkylation of DNA bases causing cross-linking

Correct Answer: Inhibition of thymidylate synthase leading to decreased dTMP and impaired DNA synthesis

Q2. Chemically, floxuridine is best described as:

  • An anthracycline antibiotic
  • A platinum-based alkylating agent
  • A fluoropyrimidine deoxyribonucleoside (5-fluoro-2′-deoxyuridine)
  • A vinca alkaloid

Correct Answer: A fluoropyrimidine deoxyribonucleoside (5-fluoro-2′-deoxyuridine)

Q3. The most common clinical application for floxuridine is:

  • First-line therapy for acute lymphoblastic leukemia
  • Regional treatment of colorectal cancer liver metastases via hepatic arterial infusion
  • Adjuvant therapy for early stage breast cancer
  • Maintenance therapy in chronic myeloid leukemia

Correct Answer: Regional treatment of colorectal cancer liver metastases via hepatic arterial infusion

Q4. Which route of administration is most characteristic for achieving high hepatic concentrations of floxuridine?

  • Oral tablets taken daily
  • Intramuscular injection
  • Continuous hepatic arterial infusion
  • Subcutaneous depot injection

Correct Answer: Continuous hepatic arterial infusion

Q5. The active metabolite of floxuridine that inhibits thymidylate synthase is:

  • 5‑fluorouridine triphosphate (FUTP)
  • 5‑fluorodeoxyuridine monophosphate (FdUMP)
  • 5‑fluorouracil (5‑FU)
  • 5‑fluoroacetate

Correct Answer: 5‑fluorodeoxyuridine monophosphate (FdUMP)

Q6. Which adverse effect is most commonly associated with floxuridine therapy?

  • Severe peripheral neuropathy
  • Profound myelosuppression (bone marrow suppression)
  • Ototoxicity
  • Nephrogenic diabetes insipidus

Correct Answer: Profound myelosuppression (bone marrow suppression)

Q7. Why does hepatic arterial infusion of floxuridine reduce systemic toxicity compared with systemic IV administration?

  • Floxuridine is inactivated by intestinal flora before reaching the circulation
  • The liver extracts and metabolizes a large fraction on first pass, providing high local exposure and lower systemic levels
  • The drug binds irreversibly to serum albumin in the portal vein
  • Hepatic infusion causes rapid renal clearance

Correct Answer: The liver extracts and metabolizes a large fraction on first pass, providing high local exposure and lower systemic levels

Q8. Which laboratory tests are most important to monitor during floxuridine therapy?

  • Blood glucose and thyroid function tests
  • Complete blood count (CBC) and liver function tests (LFTs)
  • Urinalysis and serum amylase
  • Serum electrolytes only

Correct Answer: Complete blood count (CBC) and liver function tests (LFTs)

Q9. A common cellular mechanism by which tumors develop resistance to floxuridine is:

  • Overexpression of thymidylate synthase
  • Increased expression of topoisomerase II
  • Enhanced microtubule stabilization
  • Excessive drug glucuronidation by UDP‑glucuronosyltransferase

Correct Answer: Overexpression of thymidylate synthase

Q10. Floxuridine should be avoided in pregnancy primarily because it is:

  • An effective antiemetic that suppresses fetal appetite
  • Teratogenic and embryotoxic due to interference with DNA synthesis
  • Associated with maternal hypertension only
  • Neutral and safe during all trimesters

Correct Answer: Teratogenic and embryotoxic due to interference with DNA synthesis

Q11. Compared with 5‑fluorouracil (5‑FU), floxuridine is:

  • Identical in all pharmacologic properties and use
  • A deoxynucleoside analog that more readily yields FdUMP and shows high hepatic extraction
  • A platinum compound unrelated to fluoropyrimidines
  • A pure RNA polymerase inhibitor

Correct Answer: A deoxynucleoside analog that more readily yields FdUMP and shows high hepatic extraction

Q12. Which gastrointestinal toxicities are commonly seen with floxuridine?

  • Constipation and decreased appetite only
  • Severe diarrhea and mucositis (stomatitis)
  • Painless rectal bleeding only
  • Hypersecretion of bile with no mucosal effects

Correct Answer: Severe diarrhea and mucositis (stomatitis)

Q13. The pharmacokinetic profile of floxuridine is characterized by a:

  • Very long elimination half‑life allowing once‑monthly dosing
  • Short systemic half‑life with rapid hepatic metabolism and extraction
  • Exclusive renal elimination with accumulation in renal failure
  • Depot formation in adipose tissue

Correct Answer: Short systemic half‑life with rapid hepatic metabolism and extraction

Q14. Dose modifications for floxuridine are most critically considered in patients with:

  • Severe hepatic impairment rather than mild renal impairment
  • Mild hypocalcemia only
  • Stable chronic kidney disease without hepatic disease
  • Uncontrolled hyperthyroidism only

Correct Answer: Severe hepatic impairment rather than mild renal impairment

Q15. FdUMP inhibits thymidylate synthase by forming a stable ternary complex with the enzyme and:

  • Uridine monophosphate (UMP)
  • 5,10‑methylene tetrahydrofolate (5,10‑CH2‑THF)
  • ATP and magnesium
  • DNA polymerase alpha

Correct Answer: 5,10‑methylene tetrahydrofolate (5,10‑CH2‑THF)

Q16. The effect of co‑administering leucovorin (folinic acid) with floxuridine is to:

  • Antagonize floxuridine and reduce efficacy
  • Stabilize the FdUMP–TS–folate complex and potentiate cytotoxicity
  • Increase renal clearance of floxuridine
  • Directly inhibit drug‑metabolizing enzymes to prolong half‑life

Correct Answer: Stabilize the FdUMP–TS–folate complex and potentiate cytotoxicity

Q17. For regional liver therapy, floxuridine is typically administered as:

  • An oral tablet once daily
  • A short bolus IV push only
  • A continuous or prolonged infusion into the hepatic artery
  • A topical application over the skin

Correct Answer: A continuous or prolonged infusion into the hepatic artery

Q18. When used with radiotherapy, floxuridine acts as a:

  • Radioprotective agent that reduces radiation side effects
  • Radiosensitizer that can enhance radiation cytotoxicity
  • Contrast agent for imaging
  • Pure antiemetic adjunct

Correct Answer: Radiosensitizer that can enhance radiation cytotoxicity

Q19. Hepatic arterial infusion of floxuridine may cause which specific hepatic complication?

  • Acute cholangitis caused by bacterial seeding only
  • Biliary sclerosis and focal hepatic toxicity due to regional exposure
  • Autoimmune hepatitis in all patients
  • Complete sparing of hepatic parenchyma with no toxicity

Correct Answer: Biliary sclerosis and focal hepatic toxicity due to regional exposure

Q20. Floxuridine primarily affects which macromolecular synthesis pathway in cancer cells?

  • DNA synthesis more than RNA synthesis
  • Lipid synthesis only
  • Protein glycosylation exclusively
  • Mitochondrial electron transport chain only

Correct Answer: DNA synthesis more than RNA synthesis

Q21. Which hematologic toxicity often necessitates treatment delays or dose reductions with floxuridine?

  • Thrombocytosis
  • Neutropenia
  • Polycythemia vera exacerbation
  • Elevated eosinophil count without symptoms

Correct Answer: Neutropenia

Q22. Intracellular activation of floxuridine to its inhibitory nucleotide primarily requires phosphorylation by:

  • Cytochrome P450 enzymes
  • Dihydropyrimidine dehydrogenase (DPD)
  • Cellular kinases such as thymidine kinase
  • Monoamine oxidase

Correct Answer: Cellular kinases such as thymidine kinase

Q23. Does floxuridine undergo significant cytochrome P450–mediated metabolism?

  • Yes — CYP3A4 is the main elimination pathway
  • No — it is primarily metabolized by cellular enzymes and hepatic extraction, not major CYP pathways
  • Only CYP2D6 metabolizes floxuridine extensively
  • Only intestinal CYPs activate it to an active metabolite

Correct Answer: No — it is primarily metabolized by cellular enzymes and hepatic extraction, not major CYP pathways

Q24. Patient counseling for reproductive safety with floxuridine should include:

  • No need for contraception during therapy
  • Use of effective contraception during treatment and for a recommended period after therapy
  • Only male patients need contraception
  • Contraception is unnecessary if the patient is using topical barrier methods

Correct Answer: Use of effective contraception during treatment and for a recommended period after therapy

Q25. In the event of life‑threatening fluoropyrimidine toxicity or overdose, which antidote is available?

  • Acetylcysteine
  • Uridine triacetate (uridine rescue)
  • Methotrexate
  • Atropine

Correct Answer: Uridine triacetate (uridine rescue)

Q26. Which laboratory abnormality most directly indicates hepatic toxicity from floxuridine?

  • Marked hypokalemia
  • Elevated transaminases (ALT/AST) and cholestatic markers
  • Isolated hyperglycemia
  • Low serum ferritin only

Correct Answer: Elevated transaminases (ALT/AST) and cholestatic markers

Q27. The chemical name 5‑fluoro‑2’‑deoxyuridine indicates floxuridine is a:

  • Purine analog
  • Pyrimidine deoxynucleoside analog
  • Steroid hormone
  • Polypeptide antibiotic

Correct Answer: Pyrimidine deoxynucleoside analog

Q28. Which systemic chemotherapy agents are commonly used in combination strategies for metastatic colorectal cancer where regional floxuridine might be part of the plan?

  • Oxaliplatin or irinotecan as part of combination regimens
  • Anastrozole and tamoxifen only
  • Imatinib monotherapy exclusively
  • Interferon alpha without cytotoxics

Correct Answer: Oxaliplatin or irinotecan as part of combination regimens

Q29. Which clinical sign should prompt immediate evaluation for severe toxicity during floxuridine therapy?

  • Mild hair thinning without systemic symptoms
  • High fever, severe mucositis, and neutropenia suggestive of febrile neutropenia
  • Transient mild headache that resolves
  • Intermittent mild pruritus with normal labs

Correct Answer: High fever, severe mucositis, and neutropenia suggestive of febrile neutropenia

Q30. Practical pharmacy handling for floxuridine preparations should emphasize:

  • Aseptic technique, accurate dosing, and timely administration due to short stability and potent toxicity
  • Keeping vials at room temperature for weeks after reconstitution
  • Mixing with any available IV fluid without compatibility checks
  • Labeling as non‑hazardous cytotoxic waste

Correct Answer: Aseptic technique, accurate dosing, and timely administration due to short stability and potent toxicity

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