What is the major difference between distribution of amphotericin and 5-FC?
5-FC distributes into CNS
What is the mechanism of action of 5-FC?
5-FC is a pyrimidine antimetabolite that is accumulated in fungal cells by the action of a membrane permease and converted by cytosine deaminase to 5-FU, an inhibitor of thymidylate synthase
What are the clinical uses of 5-FC?
In combination with amphotericin B or a triazole, of infections resulting from Cryptococcus neoformans, possibly systemic candidal infections and chromoblastomycosis caused by molds
Why 5-FC is not toxic to mammalian cells?
Because mammalian cells have low levels of permease and deaminase
What are the SE of 5-FC?
reversible bone marrow depression, alopecia, and liver dysfunction
Which of the Azoles has mainly renal clearance?
Which azole has excellent CNS penetration?
Which Azoles are better absorbed from GI?
Fluconazole and Voriconazole
What is the mechanism of action of azoles?
The azoles interfere with fungal cell membrane permeability by inhibiting the synthesis of ergosterol. These drugs act at the step of 14-demethylation of lanosterol, which is catalyzed by a fungal cytochrome P450 isozyme.
What is the clinical use of ketokonazole?
chronic mucocutaneous candidiasis
What are the clinical uses of fluconazole?
1. DOC for Esophageal and oropharyngeal candidiasis and for most infections caused by Coccidioides.
2. A single oral dose usually eradicates vaginal candidiasis.
3. Fluconazole is the drug of choice for treatment and secondary prophylaxis against cryptococcal meningitis and is an alternative drug of choice (with amphotericin B) in treatment of active disease due to Cryptococcus neoformans.
4. The drug is also equivalent to amphotericin B in candidemia.
What are the main clinical uses of itraconazole?
1. Systemic infections caused by Blastomyces and Sporothrix and for subcutaneous chromoblastomycosis
also an alternative for other endemic fungi
3. In esophageal candidiasis, the drug is active against some strains resistant to fluconazole.
4. treatment of dermatophytoses, especially onychomycosis.
What are the clinical uses of voriconazole?
codrug of choice for treatment of invasive aspergillosis
Also systemic candidemia and resistant candida in AIDS patients
What is the broadest spectrum of azoles?
What are the clinical use of posaconazole?
1. Most species of Candida and Aspergillus.
2. It is the only azole with activity against the agent of mucormycosis
3. Prophylaxis of fungal infections during cancer chemotherapy
4. salvage therapy in invasive aspergillosis.
What is the only azole with activity against mucormycosis?
What is the main SE of all azoles?
Drug interactions and hepatic dysfunction
Which azole interfere with steroid biosynthesis?
What is the unique SE of voriconazole?
immediate but transient visual disturbances including blurring of vision
What are the echinocandins?
Caspofungin, anidulafungin (longest HL) and micafungin
What is the mechanism of action of echinocandins?
inhibiting the synthesis of (1-2)glycan, a critical component of fungal cell wall
What are the clinical uses of echinocandins?
Severe , resistant (to ampho B-->caspofungin) or systemic canididal infection