Antimicrobial OBJECTIVES Flashcards
prophylactic coverage
attempt to prevent an infection before it is encountered
often done before surgery
empiric coverage
giving an antibiotic that will cover all of the most likely pathogens affiliated with a particular infection
not sure what it is so cover for all while getting a culture to narrow down
targeted coverage
give antibiotics for a specific pathogen
helps eliminate unnecessary and excessive coverage
broad spectrum
antibiotic that treats/covers a variety of organisms
typically both gram positives and gram negatives (and resistant organisms)
when would you use broad spectrum Abx?
used for empiric/initial treatment of suspected infection
narrow spectrum
antibiotic with limited pathogen coverage
may be due to nature of antibiotic or resistance issues
when would you use narrow spectrum Abx?
for treatment of specific pathogen (via culture or patient history)
bacteriostatic agents
antimicrobials that inhabit bacterial GROWTH
requires host immune system to eliminate bacteria that are there
bactericidal agents
antimicrobial that directly destroys the bacteria
used in patients who are immunocompromised (no immune system to fight what is left) or serious infections
bioavailability
% of a drug that gets into the body when given orally as compared to IV
drugs with high bioavailability have same IV doses and PO doses
what factors must be considered when prescribing antibiotics to the elderly?
different dosing due to
- muscle wasting
- renal dysfunction
- adverse events
reduced renal function and antibiotics
often found in elderly
may potentially underdose an antibiotic
elderly and adverse events
more susceptible
i.e. cephalosporins can cause hallucinations
must reduce the dose or we will overdose and do harm
steps in selecting an antibiotic regimen
- consider infection (site. common organism, PO/IV)
- consider patient (age, allergies, renal, CI)
- cost effective
- don’t be redundant – most coverage, no duplicate coverage, different targets)
- be convenient (appropriate dosing, PO are better)
goals of antimicrobial stewardship (4)
- reduce complications and risk of adverse events
- improve outcomes
- use more cost effective regimens
- reduce emergence of bacterial resistance
benefits of antimicrobial stewardship
- reduce C diff rates
- reduce resistance rates
- improve approbate use and clinical outcomes
- reduce cost of care (less spending on Abx, fewer readmissions, lower resistance rates, decrease complications)
why are beta lactams preferred over other antibiotics?
work quickly
potent
bactericidal
mechanism of action Beta lactams
cause bacterial cell wall
bactericidal, potent and rapidly kill bacteria
drug of choice when they are susceptible
drug of choice for syphilis
penicillin
drug of choice for MSSA bacteremia
IV Antistaaphyloccocal penicillin
nafcillin/oxacillin
drug of choice for enterococcal infections
aminopenicillins
beta lactamases
enzymes produced by bacteria that render beta lactam antibiotics ineffective
make bacteria more resistant to Abx
Beta lactamase inhibitors increased spectrum by:
adding coverage of
Gram -,
staph species,
strep pneumoniae
Beta lactamase inhibitors
drugs that inhibit beta lactamase in bacteria
when would we use extended spectrum penicillins
severe or healthcare associated infections
+
concern for resistant gram negative organisms
(not used for targeted therapy, too broad)
1st gen Cephalosporins use
prophylaxis (before surgery over skin)
epic uncomplicated cellulitis
targeted therapy if sensitivities are known
which cephalosporins have aerobic coverage?
cefoxitin and cefotetan
2nd generation cephalosporins
used prophylactically during intra-abdominal surgeries
3rd generation cephalosporins
ceftriazone
great overage of strep pneumoniae
ceftazidime –> pesudamonas
used for empiric and targeted
4TH gen cephalosporins dont cover
ESBLs, Enterococcus, anaerobes or MRSA
carbapenems
meropenem
broadest of all antibiotic classes
only thing they don’t cover is MRSA
which antibiotic has the broadest spectrum?
carbapenems
when do we used carbapenems
patients with nosocomial infections
reisitnat organisms are suspected
drug of choice for ESBL producing gram negatives
what drugs can be given to a patient with allergies to Beta lactams?
carbapenems
monobactams (Azotreonam)
monobactams
ONLY gram negatives (no gram +)
can be used safely in patients who report anaphylaxis to beta lactams
antibiotics that require peak and trough blood levels
aminoglycosides, vancomycin
peak = efficacy, trough = toxicity
which antibiotics have black box warnings?
fluroquinolones
clindamycin
black box warning:
flouroquinolones
tendon rupture and/or inflammation
exacerbation of myasthenia gravis
black box warning:
clindamycin
high propensity to cause C. diff
avoid in its at risk (elderly, cancer, freq. Abx use)
antivirals effective against HSV
acyclovir and valacyclovir (DOC)
famciclovir
who is at risk of CMV infection?
immunocompromised patients
- HIV
- transplant pts
- cancer patients
which antivirals are effective against respiratory viruses
oseltamivir and zanamivir
tamiflu, relenza
which patients should receive influenza treatment?
patients who require hospitalization
has severe, complicated or progressive illness
high risk of complications
Systemic Azoles
narrow to broad spectrum
Fluconazole < itraconazole < vorioconazole < Posconazole
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Aspergillis coverage
Voriconazole (DOC)
intraconazole
IV echinocandins
terbinafine indications
PO
AKA Lamasil
onychomycosis
terbinafine treatment
AKA Lamasil
6 weeks: fingernails
12 weeks: toenail
how do you treat CMV?
ganciclovir (IV)
valganciclovir (PO)
difference b/t echinocandins and azoles?
a: many drug interactions, increase hepatoxicity, PO or IV, more common
e: IV only, more broad, safer (less adverse event or toxicity)
which anti fungal should be used for empiric treatment of fungemia and invasive candidasis
fluconazole
exhoniocandadiasis
