Infectious Diseases III: Antifungals & Antivirals Flashcards
Amphotericin B MOA
binds to ergosterol, altering cell membrane permeability and causing cell death
Amphotericin B formulations
Amphotericin B deoxycholate = conventional, many toxicities
Amphotericin B lipid formulation = fewer toxicities compared to conventional
Amphotericin B Boxed warning
mixing between conventional and lipid formulation, conventional should not be more than 1.5mg/kg/day can cause cardiopulmonary arrest and death
Ampthotericin B Side effects
infusion related, fevers, chills, headache, dec K/Mg, nephrotoxicity
** conventional req premed to reduce incidence **
Amphotericin B DI
additive risk with other nephrotoxic agents
can inc risk of digoxin toxicity, use caution with any other agent that dec K/Mg
Flucytosine MOA
goes inside cells, converts to fluorouracil and interferes with fungal RNA and protein synthesis
using in combo with Amp B due to resistance
Flucytosine and AmpB combo used in….
invasive cryptococcal (meningitis) or candida infections
Azole MOA
decrease ergosterol synthesis and cell membrane formation
Fluconazole info
only azole that req renal dose adjustment, rest cleared hepatically
works against C.albicans, parapsilosis and tropicalis
Limited activity against C. glabrata and C kruse = resistant
primary use for itraconazole?
dimorphic fungi (blastomycoses & histoplasma)
nail bed infections
Voriconazole is treatment of choice for….
aspergillus
which azole can treat fungal meningitis?
fluconazole and voriconazole, both penetrate the CNS
Itraconazole boxed warning
can worsen or cause HF, dont used to treat onychomycosis in pts with ventricular dysfunction or hx of HF
Ketoconazole warnings
hepatotoxicity which has led to liver transplantation or death
QT prolongation
use only as last resort
Voriconazole warnings and SE
SE: visual changes, inc LFTs, Scr, CNS tox
Warnings: hepatotoxicity, visual disturbances, phototox, QT prolong
avoid direct sunlight, caution driving at night
** take on empty stomach **
Isavuconazonium info
causes QT shortening not prolongation
micron filter req when admin IV
Azole drug interactions
Itraconazole/ketoconazole req acidic environment, so if on PPI drink soda before taking
PPI can dec absorption of posaconazole suspension, dont take w/ it
Echinocandins (-fungins) MOA
inhibit synthesis of beta (1,3) D-glucan, part of fungal cell wall
active against candida species, used in combo against Aspergillus
Echinocandins info
all given once daily
no dose adjustments in renal impairment
Micafungin req light protection during admin
Griseofulvin info
used for fungal infection of skin, hair,nails
dont use in pregnant people, severe liver disease
take w/ fatty meal to inc absorb and dec GI upset
inc metabolism of hormone BC, use backup
SE: photosensitivity, inc LFTs
Terbinafine Info
Lamictal = topical
Warning: hepatotoxicity
SE: headache, inc LFTs
empiric treatment for Candida albicans thrush
mild = topical anti fungal
mod-severe = fluconazole
alternative = Nystatin
empiric treatment for Candida albicans esophageal infection
fluconazole
alternative: echinocandin
empiric treatment for Candida kruse and globarata, all candida blood stream infections
echinocandin
alternative: amp B, high dose fluc
empiric treatment for aspergillus
Vorivonazole
alternative: amp B, isavuconazonium
Cryptococcus neoformans meningitis empiric treatment
ampB + flucytosine
alternative: high dose fluc + flucytosine
Dermatophytes empiric treatment
terbinafine or itraconazole
Alternative: fluconazole
Neuraminidase inhibitors
oseltamivir - tamiflu
zanamivir
peramivir
to be most effective, neuraminidase inhibitors should be taken within….
48hrs of illness onset
Baloxavir (Xofluza)
endonuclease inhibitor = MOA
single dose
still start within 48hrs of symptom onset
Tamiflu treatment dosing
75mg BID X 5 days ( > 12 yrs old)
Tamiflu ppx dosing
75mg QD X 10 days ( > 12 yrs old)
Tamiflu warnings and SE
Warning: neuropsych events
SE: HA, N,V
preferred in pregnancy over others
Zanamivir treatment dosing
Two 5mg inhalations BID X 5 days ( > 7yrs)
Zanamivir ppx dosing
Two 5mg inhalations QD X 10 days (> 5 yrs) if household, X 28 days if community
Zanamivir warnings
dont use in Asthma/COPD due to bronchospasm
Peramivir dosing
600mg IV single dose for txm, < 50 CrCl renal adjust
Acyclovir warning
use caution with renal impairment, elderly and the on other nephrotoxic drugs.
hydrate well and infuse over 1 hr at least
Initial oral herpes txm
Acyclovir - 200mg X 5 times daily or 400mg TID
Valacyclovir - 1g BID
Chronic suppression oral herpes txm
Acyclovir - 400mg BID
Valacyclovir - 500mg or 1g QD
HSV encephalitis txm
IV acyclovir 10mg/kg Q8H for 14-21 days
Shingles Vaccine recommendations
> 50 yrs old or > 19yrs old if immunosuppressed
Shingles txm
Acyclovir - 800mg 5 times a day for 7/10 days
Valacyclovir - 1g TID for 7 days
CMV txm of choice and what’s back up?
Ganciclovir and valganciclovir
Foscarnet and cidofovir back up
Maribavir if resistant to everything else
CMV ppx
Letermovir = getting stem cell transplant
Ganciclovir/valganciclovir = sold organ transplant
Ganciclovir/valganciclovir boxed warning
Myelosuppression
Ganciclovir/Valganciclovir notes
females use contraception during txm and 30 days after
males use contraception 90 days after
Foscarnet boxed warnings
renal impairment, pre-hydration is important
