Antibiotics Flashcards
Majority of pharyngitis cases are ___ and treated with ____
viral
nothing
If pharyngitis is caused by bacteria (only 10-15%) it is treated with ___?
GABHS - penicillin
alternative: azithromycin or cephalosporin
bacterial etiologies for Otitis Media?
Strep Pneumo - 35%
H Flu - 25%
Moraxella catarrhalis - 15%
what is treatment protocol for otitis media
observation method
if child doesn’t improve in 48-72 hours begin ab therapy
*always treat children with severe symptoms and children <6 months and children > 2 who have AOM with otorrhea
First line ab for AOM
amoxicillin
alternative: cephalosporins (ceftriaxone), macrolides (asithromycin)
when do you initiate tx for sinusitis?
after 10 days of sx which indicates bacterial infection
first line tx for sinusitis?
amoxicillin, doxycline
second line: cephalosporins, azithromycin
most common etiology of CAP
strep pneumo
h flu
mycoplasma pneumonia
etc
tx for CAP
macrolide
tx for uncomplicated cystitis
nitrofurantoin (macrobid)
cipro is second line
*avoid fluoroquinolones
uncomplicated cystitis
infection of bladder in a host without structural abnormalitis, neurological urinary abnormalitis, or signs of systemic infection (fever)
common etiology for uncomplicated cystitis
e coli - 75-95%
klebsiella
staph saprophyticus - common in post-coital
tx for gonorrhea
ceftriaxone plus azithromycin
* no fluoroquinolones due to resistance
tx for chlamydia
doxycycline
azithromycin
cellulitis tx for uncomolicated and non MRSA
amoxil-vlavulanate
dicloxacillin
cephalaxin
tx for suspicion of MRSA cellulitis
TMP sulfa
clindamycin
doxycyclin
example of narrow spectrum ab
penicillin
broad spectrum ab
piperacillin
bacteriostatic ab
tetracycline
time dependent antibiotics: maximize effect by total time in body
penicillins
cephalosporins
macrolides
clindamycin
concentration dependent antibiotics: most effective by reaching concentration above dependent activity
quinolones
aminoglycosides
azithromycin
ketolides
which antibiotics have b lactam structure
penicillins
drug of choice for n meningitidis and syphilis
penicillin
indications for aminopenicillins (ampicillin, amoxicillin)
sinusitis, otitis, lower resp tract infections, endocarditis
extended spectrum penicillins (piperacillin0
IV ONLY for severe infections - broad spectrum
what is used for anaerobes
penicillin/b-lactamase inhibitors - amoxicilin, augmentin
adverse reactions to penicillin
allergic rxn (anaphylaxis, rash, fever, urticaria) diarrhea
Type 1 IgE reaction to penicilin
within 1 hour
urticaria, flushing, angioedema of face, anaphylaxis
most severe cause of antibiotic induced diarrhea
pseudomembranous colitis (c difficile colitis) from amoxicillin and clavulanate
how are penicillins cleared?
renal
1st generation cephalosporins
cefazolin, cephalexin
used for UTIs, skin, reps
alternative to penicillins
cefriaxone
3rd generation cephalosporin
broad spectrum
used in resp infections (CAP)
what is used to treat seroius hospital infections
cefepime (4th generation cephalosporin)
adverse reactions to cephalosporins
allergic reaction
diarrhea
macrolides MOA
inhibit bacterial protein biosynthesis by binding 50s subunit - bacterostatic
macrolides
erythromycin
azithromycin
good coverage of resp infections and atypical resp pathogens
adverse reactions of macrolides
GI - nausea, vomitting, diarrhea
interact with CYP
Tetracycline MOA
inhibits protein synthesis by binding to 30s ribosomal subunit - bacteriostatic
which antibiotic classes are bacteriostatic?
macrolides, tetracycline, sulfonamides
adverse reactions of tetracycline
photosensitivity
nausea and diarrhea
tooth discoloration
sulfonamides (sulfa drugs) MOA
inhibits folic acid synthesis via enzyme inhibition
what is used to treat community acquired MRSA
sulfamethoxazole with trimethoprim
bactrim (sulfonamide) adverse reactions
allergic rash fever, photosensitivity
steven johnsons syndrome
Fluoroquinolones MOA
inhibit DNA gyrase which inhibits DNA replication and transcriptpin - bactericidal
Fluoroquinolones
levofloxacin
ciproflaxacin
potent broad spectrum
anti-anaerobes
metronidazole
clindamycin
anti-anaerobe MOA
inhibit nucleic acid synthesis
tx for MRSA
IV vancomycin
do you use penicillin to treat staph infection?
No, staph inactivates penicillin with penicilinase
What bacteria is penicillin good for
gram positive streptococci, n meningitidis
not staph
what is cephriaxone good at killing?
gram positive strep and MSSA
gram negative - very good
anaerobes - oral only
what are 4th generation cephalosporins used for?
Cefepime IV
serious hospital infections
gram neg - excellent for P. Aeruginosa
what should be avoided with tetracycline
ca or dairy products
the sun
what can cause steven johnsons syndrome?
bactrim/sulfamethoxazole with trimethoprim (bactrim)
