Pharm Ch. 42 fungi

what are fungi

very large and diverse group of microorganisms, including yeasts and molds

where can fungi be found

some are part of the normal flora of skin, mouth, intestines, and vagina; systemic, cutaneous, subcutaneous, and superficial

what is mycoses

fungal infection

what are dermatophytes

fungi that cause integumentary infections 

what is yeast

single cell fungi

reproduce by budding 

used for baking and alcoholic beverages

what is mold

multicellular

characterized by long, branching filaments called hyphae

what are 4 general types of mycotic infections

cutaneous

subcutaneous

superficial

systemic (life threatening; immunocompromised host)

what is candida albicans

may follow antibiotic therapy, antineoplastics, or immunosuppressants (corticosteroids)

may result in overgrowth and systemic infections

thrush or oral candidiasis when in mouth 

common in newborns and immunosuppressed patients

what is vaginal candidiasis

yeast infection

pregnancy, women with diabetes mellitus, women taking oral contraceptives

what are antifungal drugs

drugs used to treat infections caused by fungi 

what is ampotericin B

drug of choice for the treatment of many severe systemic fungal infections

how can antifungal drugs be administered

systemically, topically, and ophthalmic (natamycin)

how are antifungal drugs categorized

broken down by their chemical structure

what are the categories of antifungals

triazoles

echinocandins

imidazole

polyenes 

what is the mechanism of action of polyenes

bind to sterols in cell membrane lining

do not bind to human cell membranes or kill human cells

result in fungal cell death 

ex: amohotoericin B and nystatin 

what is the mechanism of action for imidazoles and triazoles

they inhibit fungal cell cytochrome P-450 enzymes, resulting in cell membrane leaking

result- altered cellular metabolism and fungal cell death

what are indications of antifungal drugs

systemic and topical fungal infections

choice of drug depends on type and location of infection

how does the drug fluconazole work

passes into the cerebrospinal fluid and inhibit the growth of cryptococcal fungi, effective in the treatment of cryptococcal meningitis

what are contraindications of antifungal drugs

drug allergy 

liver failure

kidney failure

porphyria (griseofulvin)

what are adverse effects of antifungal drugs

N/V/D

stomach pain

increased liver enzymes

use with caution in patients with renal and liver dysfunction