Week 1 Flashcards
What are on parasitic fungi?
Haustoria
What is produced by asexual and sexual reproduction of fungi?
Spore from sexual
Conidia from asexual
Mechanism of polyenes
Bind ergosterol creating holes in the membrane
Fungicidal
What are polyenes
Amphortericin B and nystatin
Spectrum of polyenes
Broad - used for invasive systemic fungal infections in immunocompromised patients both yeast and molds
Distribution of polyenes
Long half life and liposomal form can cross BBB
Adverse effects of polyenes
Nystatin is topical
Can bind cholesterol. Decreases renal blood flow 80% of patients have nephrotoxicity
What are the azoles
Fluconazole, itraconazole and ketoconazole
Mechanism of azoles
Binds fungal p450 enzyme blocking the production of ergosterol. Fungi static
Spectrum of azoles
Most widely used and spectrum varies by agent
Distribution of azoles
Orally available though acids/pop help with absorption of itraconazole and ketoconazole
Toxicity of azoles
Drug-drug interactions hepatotoxicity neurotoxicity and hormone altering. No pregnancy
Resistance of azoles
Altered p 450 enzyme
Terbinafine (lamisil) - allylamines mechanism
Fungicidal - inhibits squalene epoxidase and leads to accumulation of squalene
Spectrum of terbinafine
Dermatophytes
Toxicity of terbinafine
It’s topical. Maybe with cyp2d6 substrates
Resistance to terbinafine
Rare
Flucytosine mechanism
Messes with DNA and RNA synthesis - fungistatic
Spectrum of flucytosine
Narrow …yeast candidia albicans and cryptococcus
Distribution of flucytosine
Oral, penetrates CNS
Toxicity of flucytosine
Only partially selective for yeast…can lead to bone marrow suppression
Resistance of flucytosine
Loss of converting enzyme or transporters
Mechanism of griseofulvin
Binds micro tubules (fungistatic)
Spectrum of griseofulvin
Dermatophytes
