Introduction
Antifungal agents form a vital part of pharmacotherapy for fungal infections. This concise guide for B. Pharm students explains major classes—azoles, polyenes, echinocandins, allylamines, and flucytosine—focusing on mechanism of action, therapeutic uses, resistance, adverse effects, pharmacokinetics, drug interactions and clinical monitoring. Emphasis is placed on how agents disrupt ergosterol synthesis or fungal cell walls, indications like candidemia, cryptococcal meningitis, aspergillosis and dermatophytoses, and considerations such as nephrotoxicity, hepatotoxicity and CYP-mediated interactions. Understanding mechanism-linked toxicity and resistance helps optimize therapy. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary mechanism of action of polyene antifungals like amphotericin B?
- Inhibition of 14α-demethylase
- Binding to ergosterol and forming membrane pores
- Inhibition of β-(1,3)-D-glucan synthase
- Conversion to 5-fluorouracil and inhibition of DNA synthesis
Correct Answer: Binding to ergosterol and forming membrane pores
Q2. Which antifungal class inhibits fungal 14α-demethylase, reducing ergosterol synthesis?
- Polyenes
- Echinocandins
- Azoles
- Allylamines
Correct Answer: Azoles
Q3. Echinocandins primarily target which fungal structure or enzyme?
- Squalene epoxidase
- β-(1,3)-D-glucan synthase
- Ergosterol biosynthesis at 14α-demethylase
- DNA polymerase
Correct Answer: β-(1,3)-D-glucan synthase
Q4. Which antifungal is commonly combined with amphotericin B to treat cryptococcal meningitis induction therapy?
- Fluconazole
- Terbinafine
- Flucytosine
- Caspofungin
Correct Answer: Flucytosine
Q5. Terbinafine acts by inhibiting which fungal enzyme?
- 14α-demethylase
- Squalene epoxidase
- β-(1,3)-D-glucan synthase
- Thymidylate synthase
Correct Answer: Squalene epoxidase
Q6. First-line therapy for invasive candidemia in a hospitalized, hemodynamically unstable patient is usually:
- Oral fluconazole
- IV echinocandin (e.g., caspofungin)
- Topical nystatin
- Terbinafine oral
Correct Answer: IV echinocandin (e.g., caspofungin)
Q7. Which antifungal class is most associated with nephrotoxicity and infusion-related reactions?
- Azoles
- Polyenes (amphotericin B)
- Echinocandins
- Allylamines
Correct Answer: Polyenes (amphotericin B)
Q8. Fluconazole is preferred over itraconazole in cryptococcal meningitis primarily because:
- Fluconazole is fungicidal against Cryptococcus
- Fluconazole penetrates cerebrospinal fluid well
- Fluconazole has less drug interaction with CYP3A4
- Fluconazole is effective against mucormycosis
Correct Answer: Fluconazole penetrates cerebrospinal fluid well
Q9. Mechanisms of azole resistance in Candida species commonly include:
- Increased expression of efflux pumps and target enzyme mutation
- Overproduction of β-(1,3)-D-glucan
- Loss of ergosterol entirely
- Activation of fungal DNA repair enzymes
Correct Answer: Increased expression of efflux pumps and target enzyme mutation
Q10. Which antifungal requires therapeutic drug monitoring due to variable pharmacokinetics and narrow therapeutic index?
- Fluconazole
- Voriconazole
- Nystatin topical
- Terbinafine topical
Correct Answer: Voriconazole
Q11. Flucytosine’s antifungal action depends on conversion to 5-fluorouracil inside fungal cells. Major toxicity concern is:
- Nephrotoxicity
- Hepatotoxicity only
- Bone marrow suppression
- Peripheral neuropathy
Correct Answer: Bone marrow suppression
Q12. Drug interaction risk: Which azole is a potent inhibitor of human CYP3A4 and often causes many drug interactions?
- Fluconazole
- Ketoconazole
- Griseofulvin
- Terbinafine
Correct Answer: Ketoconazole
Q13. Which antifungal is fungistatic for dermatophytes and requires prolonged oral therapy for onychomycosis?
- Terbinafine
- Griseofulvin
- Amphotericin B
- Flucytosine
Correct Answer: Griseofulvin
Q14. Voriconazole is the drug of choice for invasive aspergillosis because:
- It has activity against Mucorales
- It achieves high CSF levels against Cryptococcus
- It has potent activity and good tissue penetration vs Aspergillus
- It is available only topically
Correct Answer: It has potent activity and good tissue penetration vs Aspergillus
Q15. Which statement about echinocandins is true?
- They are orally bioavailable and used for onychomycosis
- They inhibit ergosterol synthesis
- They are fungicidal against Candida and inhibit cell wall synthesis
- They cause frequent nephrotoxicity similar to amphotericin B
Correct Answer: They are fungicidal against Candida and inhibit cell wall synthesis
Q16. A patient on amphotericin B develops anemia. The most likely mechanism is:
- Direct bone marrow suppression by amphotericin B
- Renal potassium wasting
- Decreased erythropoietin due to renal toxicity
- Autoimmune hemolysis
Correct Answer: Decreased erythropoietin due to renal toxicity
Q17. Which antifungal is ineffective against Mucorales and may be contraindicated in mucormycosis?
- Amphotericin B
- Posaconazole
- Voriconazole
- Isavuconazole
Correct Answer: Voriconazole
Q18. For oral candidiasis (thrush) in an immunocompetent adult, the appropriate initial therapy is often:
- Systemic amphotericin B
- Topical nystatin suspension or clotrimazole troches
- IV caspofungin
- Oral terbinafine
Correct Answer: Topical nystatin suspension or clotrimazole troches
Q19. Which laboratory test is most useful for rapid identification of fungal elements in clinical specimens?
- Blood culture only
- KOH preparation of sample
- Nucleic acid amplification for bacteria
- ELISA for viral antigen
Correct Answer: KOH preparation of sample
Q20. Which antifungal requires dose adjustment in severe renal impairment because it is primarily renally excreted?
- Fluconazole
- Voriconazole
- Caspofungin
- Amphotericin B
Correct Answer: Fluconazole
Q21. Resistance via upregulation of efflux pumps most commonly reduces effectiveness of which class?
- Echinocandins
- Polyenes
- Azoles
- Allylamines
Correct Answer: Azoles
Q22. Which antifungal is primarily topical and not absorbed systemically, making it safe for localized oral or gastrointestinal candidiasis?
- Oral nystatin suspension
- IV amphotericin B
- Oral fluconazole systemic tablet
- IV voriconazole
Correct Answer: Oral nystatin suspension
Q23. Mechanism-based toxicity: Ketoconazole hepatotoxicity is related to which property?
- Strong CYP3A4 induction
- Direct mitochondrial and hepatic enzyme interference
- Binding to ergosterol in human cells
- Renal tubular damage similar to amphotericin B
Correct Answer: Direct mitochondrial and hepatic enzyme interference
Q24. Which drug is fungistatic by inhibiting microtubule function and is used for dermatophyte infections?
- Griseofulvin
- Flucytosine
- Fluconazole
- Echinocandins
Correct Answer: Griseofulvin
Q25. Appropriate therapy for mucormycosis typically includes:
- Voriconazole monotherapy
- High-dose amphotericin B (often lipid formulation) and surgical debridement
- Oral fluconazole
- Topical terbinafine
Correct Answer: High-dose amphotericin B (often lipid formulation) and surgical debridement
Q26. Which antifungal class is most likely to be administered only by intravenous infusion due to poor oral bioavailability?
- Echinocandins
- Fluconazole
- Ketoconazole oral
- Terbinafine oral
Correct Answer: Echinocandins
Q27. A serious drug interaction is likely when itraconazole is coadministered with which type of medication?
- Drugs metabolized by CYP3A4 (e.g., certain statins, benzodiazepines)
- Topical antibacterial ointments
- Oral antacids that contain magnesium
- Insulin subcutaneous injections
Correct Answer: Drugs metabolized by CYP3A4 (e.g., certain statins, benzodiazepines)
Q28. Which antifungal is most appropriate for treating tinea pedis (athlete’s foot)?
- Topical terbinafine or topical azole
- IV amphotericin B
- Oral flucytosine
- Topical amphotericin B cream
Correct Answer: Topical terbinafine or topical azole
Q29. Which statement best distinguishes fungistatic from fungicidal antifungals?
- Fungistatic agents kill fungi rapidly; fungicidal agents only inhibit growth
- Fungistatic agents inhibit fungal growth allowing immune clearance; fungicidal agents directly kill fungi
- Fungistatic drugs are always topical; fungicidal drugs are always systemic
- Fungistatic drugs work only in vivo; fungicidal drugs work only in vitro
Correct Answer: Fungistatic agents inhibit fungal growth allowing immune clearance; fungicidal agents directly kill fungi
Q30. In patients receiving long-term azole therapy, monitoring should focus on:
- Renal function only
- Hepatic function tests, potential drug interactions and therapeutic response
- Complete blood count weekly for hemolysis only
- Serum potassium exclusively
Correct Answer: Hepatic function tests, potential drug interactions and therapeutic response
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