Antifungals & Antivirals Flashcards

Terms Definitions
Ganciclovir
Activated by kinase phosphotransferase for CMV & thymidine kinase for HSV & VZV. Not a chain terminator but causes smaller, ineffective DNA fragments. Valganciclovir is the prodrug. Side effects are bone marrow suppression.
Side Effects for Ganciclovir
Bone Marrow Suppression.
Cidofovir
Cytosine nucleotide but it does not require viral activation. Coverage for HSV, VZV, CMV. Used for CMV resistant to other antivirals or patients who cannot tolerate side effects of ganciclovir (bone marrow suppression).
Foscarnet
Inorganic pyrophosphate compound. Inhibits DNA polymerase, RNA polymerase, & HIV reverse transcriptase. Major use is CSV but can be used for HSV & VZV. Nephrotoxicity
Side effects of Acyclovir
Headaches, crystallization in urine at high doses, neurotoxicity.
Drug of choice of CSV
Ganciclovir or prodrug Valganciclovir. Bone Marrow suppression is side effect. IF patient cannot handle this drug you can use Cidofovir.
Acyclovir
Activated by virus (thymidine kinase). Chain terminator and competitive inhibitor of viral DNA polymerase. Side effects include headache, crystallization in urine, neurotoxicity. Not well absorbed so prodrug valacyclovir can be used.
Flucytosine (5-FC)
Treats candida, aspergillus, & Cryptococcus (synergy). Converted by fungal cells to 5-FU & then other products inhibit DNA/RNA synthesis. Used with amphotericin B for severe infections. Bone marrow suppression is side effect
Side Effects of 5-FC (Flucytosine)
Bone marrow suppression. This antifungal covers aspergillus, candida, & used with amphotericin B for Cryptococcus.
Echinocandins
Inhibits production of 1,3, B, D glucan which is component of fungal cell wall. IV formulation only. Covers albicans including glabrata. OFten used in combination for Aspergillus. Well tolerated & not renally eliminated.
Amphotericin B
Broad spectrum. IV administration. Binds to ergosterl allowing molecules to leak in/out. First line defense for crypto, endemic fungi, second line for Aspergillus, mucormycoses. Lipid formation used for higher doses & lower toxicity. Nephrotoxicity (hypoK, hypoMg), infusion reactions, & hepatotoxicity.
Side effects of Amphotericin B
Nephrotoxicity, hepatotoxicity, infusion reactions. Broadest spectrum. IV only. USed as first line for endemic fungi, second line for aspergillus, and first line for cryptococcus.
Which Candida species is not covered by Amphotericin?
C. lusitaniae.
Azole Antifungal Side Effects
Interacts with HIV meds, Rifampin, anticonvulsants. Inhibits CYP 450. Side effects include hepatotoxicity
Azole Antifungals
Inhibits production of ergosterol by inhibiting CYP450. Covers albicans except glabrata. Covers crypto, endemic fungi, and some dermatophytes. Highly bioavailable. Hepatotoxicity. Fluco (empiric antifungal, renally cleared), Itra (non-life threatening mycoses), Vori (aspergillus first line, C. krusei), Posa (mucormycoses requires high fat meals)
Fluconazole
Empiric antifungal. The go to drug. Renally cleared so it can be used for UTIs
Itraconazole
Used for non-life threatening cases of endemic mycoses.
Voriconazole
Azole. Used as first line for aspergillus. Side effects for azoles include hepatotoxicity. Since it inhibits CYP450 there are many drug interactions including anticonvulsants, HIV meds, Rifampin.
Posaconazole
Azole. Used for mucormycoses. Requires high fat meals. Azole interacts with anticonvulsants, HIV meds, rifampin.
What candida is not covered by azoles?
Glabrata.
Adamantoanes
Prevent viral uncoding for Influenza A
Neuramindase Inhibitors
Zanamivir & oseltamivir. Inhibits viral neuramindase. Influenza A & B.
Side effects of Adamantanes
Treats Parkinson's disease also. Side effects include lightheadedness, nervousness, & inability to concentrate
First line for Aspergillus
Voriconazole. This class of drugs have lot of interactions and cause hepatotoxicity.
First line defense for endemic fungi
Amphotericin B. Broad spectrum. Side effects include nephrotoxicity, hepatotoxicity, & infusion reactions.
This class inhibits production of 1-3-b-d-glucan
Echinocandins; covers albicans, often used as combination for Aspergillus. Well tolerated. Not renally eliminated.
Antifungals that are renally eliminated
Fluconazole, Amphotericin B, Flucytosine
Which antifungal causes bone marrow suppression
5-FC, flucytosine
Which antiviral causes bone marrow suppression
Ganciclovir
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