Antifungals & Antivirals Flashcards
What are classified as fungi infections?
- yeasts
- mold
- dimorphic species
What are common yeasts that cause infections?
- Candida albicans
- Candida tropicalis
- Candida parapsilosis
- Candida glabrata
- Candida krusei
- Cryptococcus neoformans
What are common molds that cause infections?
- Aspergillus species
- Zygomycetes (Mucor and Rhizopus species; mucormycosis)
What are common dimorphic fungi that cause infections?
- Histoplasma capsulatum
- Blastomyces dermatitidis
- Coccidioides immitis
What fungi infections does Amphotericin B treat?
- Cryptococcus neoforms and most candida species (yeast)
- Aspergillus and Zygomycetes (molds)
- Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides immitis (dimorphic fungi)
Which formulation of Amphotericin B (deoxycholate or lipid formulations) is associated with less toxicity?
lipid formulations
What are boxed warnings with Amphotericin B?
- med errors with deoxycholate vs. lipid formulations have resulted in cardiopulmonary arrest and death
- Conventional amphotericin B (deoxycholate) dose should not exceed 1.5 mg/kg/day
What are SEs with Amphotericin B?
- infusion-related reactions: fever, chills, headache, malaise, rigors, hypo/hypertension, thrombophlebitis, N/V
- hypokalemia
- hypomagnesemia
- nephrotoxicity
- anemia
What SEs are specific to AmBisome?
severe back/chest pain with the first dose
What are the monitoring parameters for Amphotericin B?
- renal function
- LFTs
- electrolytes (K and Mg)
- CBC
What is the MOA of Amphotericin B?
binds to ergosterol, altering membrane permeability and causing cell death
What must Amphotericin B be diluted with for injection?
D5W
What must be done to administer lipid Amphotericin B formulations?
Lipid formulations must be filtered during preparation
What must be done to administer conventional Amphotericin B deoxycholate injection?
requires pre-medication 30-60 minutes prior to infusion to reduce infusion-related reactions
What medications are used to prevent infusion-related reactions with Amphotericin B deoxycholate?
- Acetaminophen/ NSAIDs
- diphenhydramineand/or hydrocortisone
- NS boluses to decrease the risk of nephrotoxicity
- meperidine to decrease the duration of rigors
What dosage forms of Amphotericin B are available?
injection; conventional and lipid formulations are yellow-orange in color
Amphotericin B Lipid Complex
Abeicet
Liposomal Amphotericin B
AmBisome
What drugs interact with Amphotericin B?
- additive risk of nephrotoxicity with nephrotoxic agents (aminoglycosides, cisplatin, polymixins, cyclosporine, loop diuretics, NSAIDs, radiocontrast dye, tacrolimus, vancomycin)
- increases the risk of digoxin toxicity due to hypokalemia
- caution with any agent that decreases potassium or magnesium
What is the MOA of flucytosine?
penetrates fungal cells and is converted to fluorouracil, which competes with uracil and interferes with fungal RNA and protein synthesis
Why should flucytosine not be used alone?
resistance has developed
What is flucytosine used in combination with to treat
invasive cryptococcal and candida infections?
Amphotericin B
What are boxed warnings with flucytosine?
use extreme caution in patients with renal dysfunction; monitor hematologic, renal, and hepatic status
What are SEs with flucytosine?
- dose-related myelosuppression (anemia, neutropenia, thrombocytopenia)
- increased BUN/SCr
- liver injury
- increased bilirubin
- many CNS effects
- hypoglycemia
- aplastic anemia (bone marrow stops making RBCs)
- hypokalemia