Fungi

6 flashcards · Other · by Jared Blackwell

1. Amphotericin B

   Bind to ergosterol causing pores that leak K+ causing cell death. Kinetics are non-linear; t ½ is 15 days. Can find drug up to 6 weeks later; Little drug metabolism. Start with daily injection then go to 3 times a week. Side Effect: fever & chills, cardiac arrhythmias, 1. Renal toxicity causing K+, Mg++ wasting 2. Renal tubular acidosis 3. Suppresses EPO à Anemia. Give dose of Meperidine to mitigate Fever and Chills. b. Nystatin – only used topically because very toxic. Oral candidiasis, vagina…

2. Flucytosine

   Only used for cryptococcus meningitis with addition of amphotericin B

3. Triazoles

   Bind to CYP51 blocking demethylation of Lanosterol, an ergosterol precursor. Can NOT make ergosterol causing disruption of cell membrane integrity. a. Yeasts; Cryptococcus & Candida = Fluconazole b. Dimorphic; Histoplasma, Blastomyces, Coccidiodes = Itraconazole c. Molds; aspergillus & mucorales = Voriconazole, Posaconazole, itraconazole, isavuconazole.

4. Echinocandins

   Inhibits cell wall synthesis of 1,3 B glucan by blocking interaction of UDP-glucose and glucan synthase subunit Rho Only for Candida & Aspergillus.

5. Terbinafine

   Inhibits squalene epoxidase blocking conversion of squalene to ergosterol Onychomycosis, Tinea capitis, Sporotrichosis.

6. Nikkomycin

   Chitin inhibitor used for dimorphic fungi i.e. Blastomyces, Coccidiodes.