Antifungal Chemotherapy Flashcards
What are the Dimorphic Fungi?
Histoplasma Capsulatum, Blastomyces dermatiditus,
Coccioides immitis, Sporothrix schenckii
What are the opportunisic fungi?
Candida, aspergillus, cryptococcus
What are the Cutaneous/subcutaneous fungi?
Sporothrix schenckii,
Dermadophytes: ringworm, athletes foot, onchomycosis
What fungi are included in dermatophytes?
Trychophytan, Epidermophytan, Microsporum
What are the unique targets of antifungal chemotherapy?
Fungal cell membrane(ergosterol and ergo synth),
Fungal cell walls (Glucan synth)
What are the shared targets of antifungals?
DNA/RNA synthesis, Cell division
What are the different classes of antifungals?
Polyenes, Azoles, Nucleoside analogs, echinocandins, allylamines, and microtubule inhibitors
Which drug has the broadest spectrum of antifungal activity?
Amphotericin B.
Why is Ampho B not used as much anymore?
Too many side effects. Replaced by azoles.
MOA of Ampho B?
Binds to Ergosterol in Fungal Cell membrane.
Alters membrane Permiability.
What are the main uses for Amphoteracin B?
Systemic diseases such as Candida and Cryptococcus (yeasts). and Aspergillus, Histoplasma, coccioides, blastomyces, sporothrix, and mucormycoses. (molds)
How is Ampho B administered?
Insoluable in Water. Complexed with a bile salt. High protein binding!
What are the adverse rxns of Ampho B?
Infusion related Rxns. Fever, chills, muscle spasms, vomiting. Decrease rate or dose of admin.
Nephrotoxicity (vasoconstrictive)
How is toxicity of Ampho B decreased?
Insertion into micelles.
What is the MOA of Azoles?
Inhibits ergosterol synthesis. Makes the cell membrane leaky.
What are the two groups included in Azoles?
Imidazoles and Triazoles
What types of fungi do azoles work against?
Pathogenic yeast, Systemic mycoses, and dermatophytes.
How does resistance develop to azoles?
Less ergosterol in the fungal cell membranes.
What are the adverse reactions to Azoles?
GI disturbances
Interacts with P450 in liver
What is the 1st line treatment for systemic candida, cryptococcus, and coccidiomycosis.
Fluconazole
What are the benefits of Fluconazole?
Less adverse effects.
What are the pros/cons of itraconazole?
Broader activity than fluconazole but narrow theraputic index…
What drug has replaced Ampho B for treating aspergillosis?
Voriconazole
What fungi does Posaconazole treat?
Candida, Aspergillus, and mucormycoses
What antifungal inhibits protein and nucleic acid synthesis?
Flucytocine
How is flucytosine used?
Combo therapy for cryptococcal infections.
What is the MOA of Echinocandins?
Inhibit synth of Beta-Glucans. Fungal cell wall.
What features allow echinocandins to work on only some fungi and no humans?
Only works if beta-glucan present.
Why is use of echinocandins limited?
Very expensive. used if no others work well.
What drugs are administered orally (systemically) for cutaneous and mucocutaneous infection.
Grisofulvin and Allylamines (terbafine)
What are the special properties of Griseofulvin and allylamines?
You drink it and it localizes to the Keratin containing cells.
What is the MOA of Nystatin?
Ergosterol synth (like ampho B)
What is nystatin used for?
Candida, local infections, oral and vaginal candidiasis.
What is the MOA of Allylamines?
Disrupts Ergosterol synthesis.
What drugs are included with topical allylamines?
Terbinafine, Naftifine. used for? Tinea Cruris, Tinea corporis.
What is the first line treatment for onchomycosis?
Terbinafine
