general and beta lactams Flashcards
an antibiogram shows what
susceptibility patterns
characteristics of a gram positive organism
thick cell wall, stains purple
characteristics of a gram negative organism
thin cell wall, stains pink
characteristics of an atypical organism
no cell wall, no stain
MIC
minimum inhibitory concentration
explain the rationale of synergistically using aminoglycosides and beta lactams
beta lactams allow aminoglycosides to reach the intracellular target permitting a lower dose of aminoglycosides
intrinsic resistance
resistance is natural to the organism
selection pressure resistance
antibiotics kill only susceptible bacteria and leaves behind more resistant bacteria strains that multiply
acquired resistance
bacterial DNA with resistant genes
enzyme inactivation resistance
bacteria-produced enzymes break down the antibiotic
high risk of CDI
broad spectrum penicillins and cephalosporins, quinolones, carbapenems, clindamycin* (BBW)
bacteriostatic
inhibit bacterial growth
bacteriocidal
kill bacteria
hydrophillic agents
beta lactams, aminoglycosides, vancomycin, daptomycin, polymixins
characteristics of hydrophilic agents
1-small VD = less tissue penetration; 2-renal elimination = drug accumulation & SE; 3-low intracellular conc = no atypical activity; 4-poor/mod bioavailability = IV:PO is NOT 1:1
lipophilic agents
quinolones, macrolides, rifampin, linezolid, tetracyclines
lipophilic agent characteristics
1-large VD = tissue penetration; 2-hepatic elim = DDIs & hepatotoxicity; 3-intracellular = atypical activity; 4-excellent bioavailability = IV:PO is 1:1
spectrum of penicillins: natural, antistaphylococcal, aminopenicillines, extended-spectrum
Natural-strep/entero/gram+ anaerobes; Antistaphylococcal- strep/MSSA; Aminopenicillins- strep/enter/gram neg(HNPEK); Extended-spectrum- gram pos and neg(pseudamonas, CAPES)
Penicillin G Benzathine BBW
not for IV use (must use IM); can cause cardiorespiratory arrest and death
zosyn
pip/taz
augmentin
amoxicillin/clavulanate
unasyn
ampicillin/sulbactam
penicillins contraindication
CrCl<30 ml/min
what is the rationale behind using probenecid with penicillins
probenecid can inc levels of beta lactams by interfering with renal excretion
t/f: all beta lactams enhance the anticoagulation effect of warfarin
f; all except nafcillin and diclozacillin
accumulation of penicillins put patients at inc risk of
seizure
first line tx for pharyngitis
penicillin VK
first line tx for AOM
amoxicillin, augmentin (also for nasal pharyngitis)
drug of choice for infective endocarditis prophylaxis before dental procedures
amoxicillin
drug of choice for syphilis
Penicillin G benzathine (G for george from grey’s)
drugs that have exposure dependent dosing
vancomycin, macrolides, tetracyclines, polymixins
drugs that have time dependent dosing
beta lactams
drugs that have concentration dependent dosing
aminoglycosides, quinolones, daptomycin
the gram __(negative/positive)___ spectrum of cephalosporins ___(inc/dec)___ with each generation
negative; inc
cephalosporins have no activity against
enterococci and atypical organisms
first gen cephalosporins and which one(s) has IV formulation
cefazolin (IV), cephalexin, cephadroxil
second gen cephalosporins and which one(s) has IV formulation
IV: cefuroxime (also PO), cefotetan, cefoxitin; PO only: cefaclor, cefprozil
second gen cephalorsporins with gram negative anaerobe activity
cefotetan, cefoxitin
third gen cephalosporins and which one(s) has IV formulation
IV: ceftriaxone, cefotaxime, ceftazidime; PO: cefdinir, cefixime, cefpodoxime
third gen cephalosporin that covers pseudemonas
ceftazidime
fourth gen cephalosprin
cefepime
fifth gen cephalosporin
ceftaroline
only beta lactam that covers MRSA
ceftaroline
beta lactamase inhibitors may be used with cephalosporins to inc acitivty against
MDR gram negative rods
ceftriaxone contraindication
hyperbilirubinemic neonates, concurrent use with Ca-containing IV products in neonates <28 days (can form precipitates with Ca)
cefotetan warning
inc risk of bleeding/disulfram rxn if ingested with alcohol due to NMTT side chain
cephalosporin SE
seizures (renal accumulation), GI upset, diarrhea, rash/allergy, hemolytic anemia
ceftriaxone clinical pearl
no renal adjustments!
cephalosporin DDIs
separate from antacids; avoid H2RAs and PPIs
carbapenems are generally reserved for
MDR gram neg
ertapenam must only be diluted in
NS
carbapenem major DDI
dec serum conc of valproic acid
invanz
ertapenem
ertapenem does not cover
pseudamonas, enterococcus, acinetobacter (PEA)
carbapenems do not cover
atypicals, VRE, MRSA, C diff, stentrophomonas
CAPES
citrobacter, acinetobacter, providencia, enterobacter, serratia
aztreonam spectrum
gram neg, CAPES, pseudamonas (no gram pos or anaerobic activity)