Fungal infections: antifungal pharmacotherapy MCQs With Answer

Fungal infections: antifungal pharmacotherapy MCQs With Answer

Introduction: This quiz collection is tailored for M.Pharm students studying Pharmacotherapeutics II (MPP 202T) and focuses on antifungal pharmacotherapy. Questions deepen understanding of mechanisms of action, clinical uses, pharmacokinetics, adverse effects, resistance mechanisms, therapeutic drug monitoring, and formulation differences of major antifungal classes (polyenes, azoles, echinocandins, pyrimidine analogs, allylamines). Each MCQ is crafted to reflect clinical and pharmacological nuances relevant to postgraduate study and exam preparation. Use these items to test applied knowledge, reinforce decision-making for antifungal selection, and review high-yield facts necessary for managing systemic and superficial mycoses.

Q1. Which of the following best describes the primary mechanism of action of azole antifungals?

• Inhibition of fungal DNA synthesis by incorporation of false nucleotides
• Inhibition of 14α-demethylase (lanosterol demethylase), blocking ergosterol synthesis
• Binding to ergosterol and forming membrane pores leading to cell leakage
• Inhibition of 1,3-β-D-glucan synthase, impairing cell wall synthesis

Correct Answer: Inhibition of 14α-demethylase (lanosterol demethylase), blocking ergosterol synthesis

Q2. Amphotericin B exerts its antifungal effect primarily by which mechanism?

• Inhibition of ergosterol synthesis via lanosterol demethylase blockade
• Conversion to 5-fluorouracil inside fungal cells, inhibiting DNA/RNA synthesis
• Binding to ergosterol and forming transmembrane pores that increase membrane permeability
• Inhibition of microtubule assembly in fungal cells

Correct Answer: Binding to ergosterol and forming transmembrane pores that increase membrane permeability

Q3. Flucytosine (5-FC) is selectively toxic to fungi because it:

• Directly binds ergosterol and disrupts membranes
• Is converted within fungal cells to 5-fluorouracil, which inhibits DNA and RNA synthesis
• Inhibits 1,3-β-D-glucan synthase in the fungal cell wall
• Blocks fungal squalene epoxidase leading to squalene accumulation

Correct Answer: Is converted within fungal cells to 5-fluorouracil, which inhibits DNA and RNA synthesis

Q4. Echinocandins (e.g., caspofungin) act by which of the following mechanisms?

• Inhibiting ergosterol synthesis via lanosterol demethylase
• Inhibiting 1,3-β-D-glucan synthase, reducing cell wall β-glucan
• Binding to ergosterol and creating membrane channels
• Interfering with fungal mitochondrial respiration

Correct Answer: Inhibiting 1,3-β-D-glucan synthase, reducing cell wall β-glucan

Q5. Which antifungal agent is typically fungistatic rather than fungicidal against most yeasts?

• Amphotericin B
• Fluconazole
• Caspofungin
• Terbinafine

Correct Answer: Fluconazole

Q6. Which formulation of amphotericin B is associated with the lowest risk of nephrotoxicity?

• Amphotericin B deoxycholate (conventional formulation)
• Liposomal amphotericin B (e.g., Ambisome)
• Amphotericin B lipid complex
• Amphotericin B colloidal dispersion

Correct Answer: Liposomal amphotericin B (e.g., Ambisome)

Q7. Among the systemic azoles, which one has the least potent inhibition of human CYP3A4 and therefore relatively fewer CYP3A4-mediated drug interactions?

• Itraconazole
• Voriconazole
• Posaconazole
• Fluconazole

Correct Answer: Fluconazole

Q8. The preferred oral treatment for esophageal candidiasis in an adult patient is:

• Topical nystatin swish and spit
• Oral fluconazole
• Oral terbinafine
• Intravenous amphotericin B

Correct Answer: Oral fluconazole

Q9. First-line therapy for invasive pulmonary aspergillosis in most patients is:

• Fluconazole
• Voriconazole
• Oral terbinafine
• Nystatin

Correct Answer: Voriconazole

Q10. Terbinafine’s antifungal action involves inhibition of which enzyme?

• Lanosterol 14α-demethylase
• Squalene epoxidase
• 1,3-β-D-glucan synthase
• Thymidylate synthase

Correct Answer: Squalene epoxidase

Q11. A common mechanism by which Candida species develop resistance to azole antifungals is:

• Decreased expression of 1,3-β-D-glucan synthase
• Overexpression of efflux pumps and mutations in ERG11 (lanosterol demethylase)
• Increased conversion of flucytosine to 5-FU
• Increased uptake of amphotericin B

Correct Answer: Overexpression of efflux pumps and mutations in ERG11 (lanosterol demethylase)

Q12. Therapeutic drug monitoring (TDM) is routinely recommended for which antifungal to optimize efficacy and reduce toxicity?

• Fluconazole
• Voriconazole
• Amphotericin B
• Nystatin

Correct Answer: Voriconazole

Q13. A characteristic laboratory abnormality associated with amphotericin B therapy is:

• Hyperkalemia
• Hypokalemia
• Hypercalcemia
• Hypermagnesemia

Correct Answer: Hypokalemia

Q14. The most clinically important hematologic toxicity of flucytosine is:

• Hemolytic anemia due to immune complexes
• Aplastic or dose-related bone marrow suppression (pancytopenia)
• Microangiopathic hemolysis
• Polycythemia

Correct Answer: Aplastic or dose-related bone marrow suppression (pancytopenia)

Q15. Echinocandins have minimal or no activity against which of the following pathogens?

• Candida albicans
• Aspergillus fumigatus (some activity)
• Cryptococcus neoformans
• Candida glabrata

Correct Answer: Cryptococcus neoformans

Q16. Which systemic antifungal is especially preferred for dermatophyte infections of the nail (onychomycosis) due to high nail concentrations?

• Fluconazole
• Terbinafine
• Voriconazole
• Amphotericin B

Correct Answer: Terbinafine

Q17. Which antifungal is well known to cause transient visual disturbances and photosensitivity as notable adverse effects?

• Fluconazole
• Itraconazole
• Voriconazole
• Ketoconazole

Correct Answer: Voriconazole

Q18. For mild oral thrush (oropharyngeal candidiasis), the commonly used topical agent is:

• Intravenous amphotericin B
• Oral terbinafine tablets
• Nystatin oral suspension (swish and swallow)
• Oral voriconazole

Correct Answer: Nystatin oral suspension (swish and swallow)

Q19. Which serum biomarker assay is most useful for diagnosing invasive aspergillosis?

• Cryptococcal antigen (CrAg)
• Galactomannan antigen assay
• Blood culture for Candida only
• Prostate-specific antigen (PSA)

Correct Answer: Galactomannan antigen assay

Q20. Which antifungal azole has notable activity against Mucorales and is used as salvage therapy for mucormycosis?

• Fluconazole
• Voriconazole
• Posaconazole
• Terbinafine

Correct Answer: Posaconazole

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