Cell Wall inhibitors Flashcards
What is the mechanism of action of B lactams?
- Bind PBPs
- inhibit transpeptidation
- inhibit cross linking
What are the three mechanisms of resistance
- enzymatic destruction -B lactamase -PBP
- alternation in porin channel
- change affinity of PBPs
What is the drug of choice for MRSA?
vancomycin
What are the two drugs of the narrow spectrum penicillins?
penicillin G - parenteral
penicillin V - oral
What is the main therapeutic use for narrow spec?
syphillis
strep (s pneum, s viridans have resistance)
mouth anaerobes - actinomyces
What are the three drugs of “very narrow spectrum” penicillins?
- methicillin
- naficillin
- oxacillin
What are the main therapeutics of M,N,O?
S aureus (NOT MRSA)
What are the two aminopenicillins?
amoxicillin and ampicillin
Why are the two aminopenicillins considered “broad spectrum”
able to enter porin channels
What are the therapeutics of aminopenicillins? What are they specifically the drug of choice for?
HHELPSS
H - h pylori H - H flu E - ecoli, enterococcus - DRUG OF CHOICE L - listeria P - proteus S - salmonella S - shigella
What are the four drugs of the extended spectrum penicillins?
- ticaracillin
- piperacillin
- azlocillin
- carbinicllin
What are the extended spec penicillins mainly used for?
pseudomonas
Which of the groups of penicllins are B lactamase resistant?
very narrow spec - M,N,O
Name some B lactamse inhibitors?
clavulonic acid, sulfbactam, tazobactam
What is augmentin?
amoxicillin and clavulanate
How are penicillins eliminated?
active tubular secretion
except Naficillin and oxacillin - Bile
What are the first generation cephalosporins?
cefazolin, cephalexin
What are the second generation cephalosporins?
cefotetan, cefaclor, cefuroxime
What are the third generation cephalosporins?
ceftriaxone, cefotaxime, cefdinir, cefixime
what are the 4 organisms that cephalosporins aren’t effective against?
LAME L - listeria A - atypicals M - MRSA E - Enterococci
What is the fourth generation cephalosporin?
cefepime
Which cephalosporins cross the BBB?
third and fourth generations plus cefuroxime
How are the cephalosporins cleared?
renal clearance
except cefoperazone and ceftriaxone - eliminated in liver
If there is allergies to lactams, what is your next drug of choice?
macrolides for gram positive
aztronam for gram negative rods
Which antibiotics cause disulfiram like effects?
cefoperazone and metronidazole
What are the carbapenams?
imipenem, meropenem, ertapenem, doripenem
What are the carbapenams MOA?
inhibit cell wall synthesis
-resistant to B lactamases
What are carbapenams mostly used for?
empirical use in nosocomial infections
abdominal polymicrobial infections
NOT MRSA
What other drug is impinem always given with and why?
cilastatin
-prevent too rapid of metabolism
How are carbapenams metabolized?
renal elimination
What is the main s/e of carbapenams?
seizures
What is the main use of aztreonam? Why are they a hidden gem?
IV drug used against gram neg rod - pseudomonas
-particularly useful if lactam allergy or renal dysfunction
What is the MOA of vancomycin?
binds D-Ala-D- ala muramyl pentapeptide
-prevents elongation of peptidoglycan chains
How does enterococcus have resistance to vancomycin? What do you use for VRE?
terminal D ala –> D lactate
linezolid and streptogratins
What are the s/e of vancomycin?
- red man syndrome - vasodilation by histamine
- ototoxicity
- nephrotoxicity
When would you be worried ab a B lactam allergy?
if it is IgE mediated
What is daptomycin used for?
VRE and VRSA
What are the first generation cephalosporins used for?
PEcKs
P - proteus
Ec - E coli
K - klebsiella
S - surgical prophylaxis
What drug is the drug of choice for surgical prophylaxis
Cefazolin
What are the second gen cephalosporins used for
HEN PEcKs
all of the PEcKs +
H - H flu **
E - enterobacter
N - neisseria
How is vanco given for C diff?
orally
Which generation of cephs have inc incidence of C diff
third
What drug specifically cannot be used for pneumonia? why?
daptomycin
inactivated by pulmonary surfactant
