EXAM #4: ANTIFUNGALS Flashcards
List the systemic fungi.
- Histoplasma capsulatum
- Blastomyces dermatiditis
- Coccidioides immitis
- Sporothrix schenckii
List the opportunistic fungi.
- Candida
- Aspergillus
- Cryptococcus neoformans
What are the common cutaneous and subcutaneous fungal infections?
Sporothrix schenckii Dermatophytes - Ringworm - Athlete's Foot - Onychomycosis
What are the unique targets used in antifungal therapy?
- Fungal cell membrane i.e. ERGOSTEROL
- Fungal cell wall i.e. GLUCANS
List the drugs that inhibit Ergosterol synthesis.
Azoles
Naftidfine
Terbnafine
What drug inhibits fungal membrane function?
Amphotericin B
What drug inhibits fungal cell wall synthesis?
Caspofungin
What drug inhibits fungal nuclei acid synthesis?
5-fluorocytosine
What drugs can be used to treat systemic fungal infections?
1) Polyenes- amphotericin B
2) Azoles
3) Flucytosine
4) Echinocandins
What drug has the broadest spectrum of all the antifungals?
Amphotericin B
Why has Amphotericin B been replaced for newer compounds?
High degree of toxicity
What is the MOA of Amphotericin B
- Binds ergosterol in fungal cell membrane
- Forms Amp B pores in fungal membrane
Why is there high toxicity associated with Amphotericin B?
Not only binds ergosterol, but can also bind cholesterol
What is Amphotericin B the treatment of choice for?
1) Disseminated candidasis
2) Cryptococcal (neoformans) meningitis
Note that it is a second line treatment for systemic disease caused by molds
What is the mechanism of resistance of Amphotericin B?
Decreased membrane ergosterol concentration
How is Amphotericin B administered?
- Note that it is INSOLUBLE in water*
- Complex-ed to a bile salt
- Given IV
How is Amphotericin B administered for Cryptococcal meningitis?
Intrathecal
What are the adverse reactions seen with Amphotericin B?
1) Infusion reaction seen in nearly all patients
2) NEPHROTOXICITY
How is the toxicity of Amphotericin B being combated?
Packaging the drug in lipid micelle i.e. “liposomal packaging”
What are the two groups of Azoles?
1) Imidazoles (2x nitrogens)
2) Triazoles (3x nitrogens)
List the imidazoles.
Ketoconazole
Miconazole
Clotrimazole