Block V- Pulm Antifungal Dugs Flashcards
Which is the broadest spectrum anti-fungal agent?
Which is the broadest spectrum anti-fungal agent?
How is Amp B administered?
IV only
What are the AE of Amp B?
- Amphoterrible (infusion related fever, chills, muscle spasms, V, H, hypotension)
- Nephrotoxic (reversible from dec. renal perfusion and irreversible from renal tubule injury w/ tubular acidosis and severe K and Mg wasting
- Hepatotoxicity
- Anemia
What is the standard therapy for life-threatening mycoses?
Amp B
What is the mechanism of action of Amp B?
- binds to ergosterol in the fungal membrane
- forms a pore and increases membrane permeability
What organisms is Amphotericin B active against?
- Candidia sp (not C. lusitaniae)
- Cryptococcus
- HIstoplasma
- Blastomyces
- Coccidiodes
- Aspergillus
- Fusarium
- Zygomyces/Mucor
What organisms is Amphotericin B NOT active against?
- Pseudallescheria boydii (Scedosporium apiosermum)
- Candidia lusitaniae
Explain a typical treatment scheme in systemic fungal ifnections
- Amphotericin B for 4 weeks of induction therapy to reduce fungal burden
- Azole treatment for consolidation therapy and prevention of relapse
Which drug is the treatment of choice for Zygomycosis/mucormycosis?
Amp B
Which drug is the only anti fungal agent that is approved for use in pregnant and breastfeeding women?
Amphotericin B
Does Flucytosine penetrate CSF?
Yes
used for treatment of Cryptococcal meningitis
Does resistance develop to Flucytosine?
Yes, restricts it’s use
-mutations in cytosine permease, cytosine deaminase, uracil phosphoribosyl transferase, inc. cytosine synthesis.
How is Flucytosine typically used clinically?
combo with Amp B or an Azole
What is the MOA of Flucytosine?
- Fungistatic
- Fungal specific cytosine deaminase
- as 5-flurouracil can inhibit RNA synthesis (5-FUTP) and DNA synthesis (FdUMP)
With what drug is Amphotericin B synergistic and why?
- Flucytosine
- inc. membrane permeability and so more flycytosine can enter the cell
Which organisms is Flucytosine active against?
- Cryptococcus neoformans
- Candida sp
- Chromoblastomycosis (tropical climates)
What are AE of Flucytosine?
- N/V/D
- Bone marrow toxicity (anemia, leukopenia, thrombocytopenia)
- Teratogenic
What is the order (narrow to broad) of Azole activity spectrum?
FIVP
Fluconazole «_space;Itraconazole < Voriconazole < Posaconazole
Why does the Azole class have many drug interactions?
They are CYP450 enzyme inhibitors and substrates of CYP450
What is the MOA of Azole drugs?
- fungistatic/fungicidal
- inhibit 14 alpha sterol demethylase to prevent synthesis of ergosterol
- impaired membrane function
- inc. membrane permeability
- dec. activity of membrane associated proteins
What are AE of ALL Azoles?
- GI distress
- Hepatotoxicity
- Teratogenic
Most drug interactions are associated with which azole drugs?
Itraconazole and Voriconazole
What are some example of drug interactions with azole drugs?
- Statins
- cyclosporins
- Benzodiazepiens
- HIV protease inhibitors
- warfarin
- digoxin
What will happen if you give a patient taking a Statin Itraconazole or Voriconazole?
Rhabodomyolysis! Never do this!
What is the spectrum of activity of Ketoconazole?
-Candidia , C neoformans
Coccidiodes, Histoplasma, Blastomyces
-dermatophytes
Does ketoconazole reach CSF or urine?
no
What are AE of Ketoconazole?
- inhibits Adrenal and Gonadal steroid synth
- Dec. cortisol and testosterone
- gyencomastia, libido, impotence, menstraul iregularities, hypotension, fatigue
Does Flucanazole reach the CSF?
Excellently so!
What are AE of FLucanazole?
-alopecia
N/V/
skin rash
GI issues