Antifungal antibiotics — Amphotericin B, Nystatin, Natamycin, Griseofulvin — are essential in B. Pharm curricula for understanding antifungal pharmacology, mechanisms, spectrum, formulations and adverse effects. Amphotericin B disrupts fungal membranes by binding ergosterol; lipid formulations reduce nephrotoxicity. Nystatin and Natamycin target ergosterol too, but are used mainly as topical or ophthalmic agents. Griseofulvin interferes with fungal mitosis and deposits in keratinized tissues, useful for dermatophyte infections. Mastery of their pharmacokinetics, resistance mechanisms, drug interactions, and monitoring is vital for safe clinical use and formulation development. These MCQs focus on mechanism, formulation differences, toxicity profiles, clinical uses and resistance — ideal for exam prep and practical understanding. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which is the primary mechanism of action of Amphotericin B?
- Binds ergosterol and forms membrane pores leading to fungal cell leakage
- Inhibits ergosterol synthesis by blocking lanosterol 14-alpha-demethylase
- Inhibits fungal cell wall synthesis by blocking beta-glucan synthase
- Disrupts fungal mitosis by binding to tubulin
Correct Answer: Binds ergosterol and forms membrane pores leading to fungal cell leakage
Q2. Which statement best describes the advantage of lipid formulations of Amphotericin B?
- Lipid formulations increase the drug’s antifungal spectrum to include bacteria
- Lipid formulations reduce nephrotoxicity compared to amphotericin B deoxycholate
- Lipid formulations allow effective oral administration
- Lipid formulations eliminate infusion-related reactions entirely
Correct Answer: Lipid formulations reduce nephrotoxicity compared to amphotericin B deoxycholate
Q3. What is the typical clinical use of Nystatin?
- Systemic life-threatening systemic mycoses via IV therapy
- Topical or oral treatment of mucocutaneous Candida infections; not given parenterally
- Primary treatment for fungal keratitis as an ophthalmic drop
- First-line oral therapy for invasive aspergillosis
Correct Answer: Topical or oral treatment of mucocutaneous Candida infections; not given parenterally
Q4. Natamycin (pimaricin) is most often used for which indication?
- Oral candidiasis systemic therapy
- Topical ophthalmic treatment of fungal keratitis
- Oral therapy for tinea capitis
- Intravenous therapy for systemic candidemia
Correct Answer: Topical ophthalmic treatment of fungal keratitis
Q5. How does Griseofulvin exert its antifungal effect?
- Binds ergosterol and forms membrane pores
- Inhibits fungal DNA synthesis by blocking thymidylate synthase
- Inhibits fungal mitosis by binding to microtubules and accumulates in keratin
- Blocks beta-glucan synthase in the cell wall
Correct Answer: Inhibits fungal mitosis by binding to microtubules and accumulates in keratin
Q6. Griseofulvin is primarily indicated for which group of infections?
- Invasive systemic candidiasis
- Dermatophyte infections of skin, hair and nails
- Ocular fungal infections such as keratitis
- Deep-seated molds like mucormycosis
Correct Answer: Dermatophyte infections of skin, hair and nails
Q7. What are the two major adverse effects associated with Amphotericin B therapy?
- Hepatotoxicity and hyperglycemia
- Infusion-related cytokine reactions and dose-dependent nephrotoxicity
- Severe neutropenia and pancytopenia
- Ototoxicity and bone marrow suppression
Correct Answer: Infusion-related cytokine reactions and dose-dependent nephrotoxicity
Q8. Co-administration of Amphotericin B with which drug class increases the risk of nephrotoxicity?
- Beta-lactam antibiotics
- Aminoglycoside antibiotics
- Azole antifungals
- Topical corticosteroids
Correct Answer: Aminoglycoside antibiotics
Q9. A common resistance mechanism against polyene antifungals (e.g., Amphotericin B, Nystatin) is:
- Increased efflux pump expression exporting polyenes out of the cell
- Alteration of tubulin proteins preventing drug binding
- Decrease or alteration of ergosterol content in the fungal membrane
- Overproduction of cell wall beta-glucan to block drug entry
Correct Answer: Decrease or alteration of ergosterol content in the fungal membrane
Q10. Which statement about Nystatin’s mechanism is correct?
- Nystatin inhibits ergosterol biosynthesis at lanosterol demethylase
- Nystatin binds ergosterol and disrupts fungal cell membrane integrity
- Nystatin inhibits fungal DNA topoisomerase II
- Nystatin is a nucleoside analog that prevents fungal replication
Correct Answer: Nystatin binds ergosterol and disrupts fungal cell membrane integrity
Q11. What is the usual route of administration for Amphotericin B for systemic fungal infections?
- Oral suspension taken with meals
- Topical cream applied to lesions
- Intravenous infusion
- Intramuscular injection into large muscles
Correct Answer: Intravenous infusion
Q12. Natamycin’s primary molecular interaction with fungi is best described as:
- Inhibition of ergosterol biosynthesis enzyme activity
- Binding ergosterol and inhibiting membrane-associated transport proteins
- Cross-linking cell wall chitin chains
- Blocking fungal DNA replication by inhibiting DNA polymerase
Correct Answer: Binding ergosterol and inhibiting membrane-associated transport proteins
Q13. Which important drug interaction is associated with Griseofulvin?
- It inhibits CYP3A4 causing increased levels of warfarin
- It induces hepatic cytochrome P450 enzymes and can reduce oral contraceptive efficacy
- It potentiates the effect of aminoglycosides causing ototoxicity
- It causes significant QT prolongation when combined with macrolides
Correct Answer: It induces hepatic cytochrome P450 enzymes and can reduce oral contraceptive efficacy
Q14. Which laboratory parameters should be monitored during Amphotericin B therapy?
- Liver transaminases only
- Serum creatinine, potassium and magnesium
- Complete lipid profile monthly
- Coagulation profile (PT/INR) daily
Correct Answer: Serum creatinine, potassium and magnesium
Q15. Which of the following is an example of a lipid formulation of Amphotericin B?
- Amphotericin B deoxycholate
- Liposomal amphotericin B (AmBisome)
- Amphotericin B oral suspension (Ampho-oral)
- Amphotericin B topical ointment
Correct Answer: Liposomal amphotericin B (AmBisome)
Q16. Why is Nystatin not used systemically?
- Because it lacks antifungal activity against Candida
- Because it is rapidly metabolized to inactive metabolites systemically
- Because of poor systemic absorption and risk of systemic toxicity
- Because it causes irreversible bone marrow suppression when given IV
Correct Answer: Because of poor systemic absorption and risk of systemic toxicity
Q17. Which formulation strategy improves oral absorption of Griseofulvin?
- Administering with a high-fat meal and using ultramicrosize formulations
- Using a chewable tablet without regard to meals
- Administering with proton pump inhibitors to increase pH
- Using an intravenous formulation instead of oral
Correct Answer: Administering with a high-fat meal and using ultramicrosize formulations
Q18. Natamycin shows best activity against which group of fungi?
- Yeasts like Candida albicans only
- Filamentous fungi such as Fusarium and Aspergillus used in ocular infections
- Systemic dimorphic fungi like Histoplasma capsulatum
- Cryptococcus neoformans causing meningitis
Correct Answer: Filamentous fungi such as Fusarium and Aspergillus used in ocular infections
Q19. Amphotericin B’s fungicidal activity is primarily because it:
- Blocks nucleic acid synthesis causing cell arrest
- Causes membrane leakage of cellular contents by forming pores
- Inhibits protein synthesis at the ribosomal 50S subunit
- Disrupts cell wall synthesis by inhibiting chitin formation
Correct Answer: Causes membrane leakage of cellular contents by forming pores
Q20. Which class of antifungals binds directly to ergosterol in fungal membranes?
- Azoles (e.g., fluconazole)
- Echinocandins (e.g., caspofungin)
- Polyenes (e.g., Amphotericin B, Nystatin, Natamycin)
- Allylamines (e.g., terbinafine)
Correct Answer: Polyenes (e.g., Amphotericin B, Nystatin, Natamycin)
Q21. Griseofulvin is contraindicated in which condition due to teratogenic risk?
- Pregnancy
- Hyperthyroidism
- Chronic renal failure
- Type 2 diabetes mellitus
Correct Answer: Pregnancy
Q22. Which electrolyte abnormalities are commonly seen with Amphotericin B therapy?
- Hypernatremia and hypercalcemia
- Hypokalemia and hypomagnesemia
- Hyperkalemia and hyperphosphatemia
- Hypocalcemia and hyponatremia
Correct Answer: Hypokalemia and hypomagnesemia
Q23. Common topical or oral dosage forms available for Nystatin include:
- IV infusion bags and intramuscular injections
- Topical creams, oral suspensions and lozenges
- Transdermal patches and ocular implants
- Rectal suppositories for systemic absorption
Correct Answer: Topical creams, oral suspensions and lozenges
Q24. How can infusion-related reactions to Amphotericin B be minimized?
- By administering Amphotericin B subcutaneously instead of IV
- By premedication with antipyretic and antihistamine agents and slowing infusion rate
- By combining with high-dose corticosteroids only after reactions occur
- By giving Amphotericin B as a rapid bolus to reduce exposure time
Correct Answer: By premedication with antipyretic and antihistamine agents and slowing infusion rate
Q25. Which property of Griseofulvin explains its effectiveness against dermatophytes?
- Its high concentration in cerebrospinal fluid
- Its deposition in keratinized tissues protecting new tissue from infection
- Its direct fungicidal pore-forming action on membranes
- Its role as a topical ophthalmic agent with poor systemic absorption
Correct Answer: Its deposition in keratinized tissues protecting new tissue from infection
Q26. When applied topically or ophthalmically, Natamycin’s systemic absorption is generally:
- Extensive, requiring frequent plasma monitoring
- Minimal, leading to limited systemic exposure
- Highly variable with risk of systemic toxicity
- Equivalent to oral bioavailability of systemic antifungals
Correct Answer: Minimal, leading to limited systemic exposure
Q27. Resistance to Griseofulvin most commonly involves which fungal alteration?
- Mutations in fungal tubulin reducing drug binding
- Increased ergosterol production in the membrane
- Overexpression of efflux pumps exporting polyenes
- Enhanced cell wall chitin synthesis blocking drug entry
Correct Answer: Mutations in fungal tubulin reducing drug binding
Q28. What is the dose-limiting toxicity for Amphotericin B that often restricts therapy?
- Severe hepatotoxicity
- Nephrotoxicity
- Irreversible ototoxicity
- Severe hypoglycemia
Correct Answer: Nephrotoxicity
Q29. Which of the following antifungals is classically described as fungistatic rather than fungicidal?
- Amphotericin B
- Natamycin
- Griseofulvin
- Nystatin
Correct Answer: Griseofulvin
Q30. Which antifungal is historically the drug of choice for tinea capitis, especially caused by Microsporum species?
- Amphotericin B
- Griseofulvin
- Natamycin ophthalmic suspension
- Intravenous Nystatin
Correct Answer: Griseofulvin
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.
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