beta lactams Flashcards
what are the different beta lactam ?
penicillins
carbapanems
aztreonam
cephalosporins
what are the carbapanems ?
imipenem
meropenem
ertapenem
what makes carbapenms different to the penicillins ?
carbapanems are resistant to cleavage by beta lactamase
what are the only antibiotics that can resist ESBL ?
carbapenems
where are ESBLs found ?
gram negative bacteria only produce ESBL
pseudomonas
klebsiella
what is the problem with impenem ?
metabolized in the kidneys and produced nephrotoxic metabolites
what enzyme breaks down imipenem and how is this problem solved ?
the enzyme is dehydropeptidase I
problem solved by giving cilastatin
specific to imipenem
what are the common side effects of carbapenem ?
GI uoset
skin rash
seizures by inhibition of GABA receptors
which of the carbapenems carries a lower risk of seizures ?
meropenem
what is the mode of action of azteronam ?
binds to penicillin binding proteins specifically PBP 3 and is resistant to beta lactamases
what are the clinical uses of aztreonam ?
used only for gram negative rods
used for patients with peniciilin sensitivity and those with renal insufficiency
what drug is synergistic with aztreonam ?
aminoglycosides
what are the 1st generation cephalosporins ?
cefazolin
cephalexin
what are the main clinical uses of first generation antibiotics ?
surgical wound skin infection
pre op prevention
what bacteria are covered by 1srt generation cephalosporins ?
PEcK
proteus
E coli
lebsiella
what are the 2nd generation cephalosporin ?
cefuroxime
cefoxitine
cefotetan
what are the bacteria that 2nd generation cephalosporins cover ?
HENS PEcK
H influenza
Enterobacter
Neisseria
Serratia
Proteus
E coi
Klebsiella
if a child were to present with E coli UTI what is the most appropriate drug to use ?
cefuroxime
no fluoroquinolones used
what drug is used for children presenting with appendicitis pre op ?
Cefoxitin / cefotetan
what are the 3rd generation cephalosporins ?
ceftriaxone ceftazidine
cefpodoxime
what is the third generation cephalosporins can be used for pseudomonal infections ?
ceftazidine
what diseases is ceftraxione commonly used for ?
meningitis
disseminated lyme disease
gonorrhea
ceftriaxone can cross the blood brain barrier
what is the 4th generation cephalosporin ?
cefepime
what is the 5th generation cephalosporin ?
ceftaroline
what does the b lactmase sensitivity depend on ?
based on the side chain
the simpler the side chain the more likely that the b lactmase will break down the antimicrobial
what is the drug of choice when it comes to ESBL bacteria ?
carbapenems
which of the cepahlosporins is active against MRSA and what is its mechanism of action ?
ceftaroline
binds to PBP2a
which is a MRSA specific PBP
also covers VRSA
what are the adverse reactions associated with cephalosporins ?
hypersensitivity reaction
vitamin k deficiency
disulfram reaction
what are the causes of bleeding in association with cephalosporin administration ?
1- vitamin K deficiency ( could happen with any antibiotic) commony a problem for patients on warfarin
2- hypoprothrombinemia
what are our sources of vitamin K ?
vitamin K1 comes from our diet
vitamin K 2 comes from GI bacteria
what type of patient is more likely to develop hypothrombonemia as a result of cephalosporin administration ?
malnourished patients
how can cephalosporins cause nephrotoxicity ?
when given with aminoglycosides
what is a disulfram reaction ?
happens with the consumption of alcohol with cephalosporins
happens due to the inhibition of aldehyde dehydrogenase enzyme
what are the organisms that are not covered by 1st to 4th cephalosporins ?
LAME
Listeria
Attypicals ( chlamydia, mycoplasma)
MRSA
Enterococci
