I would not expect you to know specific information about these specific antifungal medications. Naturally occurring resistance to antifungal drugs is extremely rare in fungi. Resistance to antifungal medications does not usually develop in fungi as it does to antibiotics in bacterial populations.

The polyenes (nystatin, amphotericin B) work by attaching to the sterol component found in the fungal membrane. This binding causes a loss of the selective permeability of the membrane causing the fungal cells to become porous and die (fungicidal). Cholesterol found in human cell membranes has a similar structure so these drugs have some toxicity in humans. Amphotericin B is used to treat serious systemic fungal diseases. Nystatin is more toxic than Amphotericin B and is not used systemically. It is used orally or topically to treat yeast infections.

The azoles (clotrimazole, ketoconazole, miconazole, fluconazole, itaconazole) have the same mechanism of action as the polyenes but are inhibitory to the fungi and less toxic to humans. Some are used topically for treating oral, skin, and vaginal infections. Fluconazole and itaconazole provide an alternative to amphotericin B in the treatment of systemic mycosis.

Griseofilvun is given orally for the treatment of severe superficial fungal infections of the skin (Ringworm, Athlete’s Foot) and diseases of the hair and nails. The drug binds to microtubules stopping cell division in fungus.

5-Fluorocytosine inhibits RNA and DNA synthesis. This drug is given in combination with amphotericin B or an azole to treat Candida and Cryptococcus infections.

Echinocandins inhibit the synthesis of a sugar that makes up part of the cell wall of fungus. This sugar does not occur in mammals; therefore, this is a safe drug to use in humans although it should not be used in pregnant women.

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