Pharm - Cephalosporins Flashcards
recap - what are the antistaph penicillins
methicillin
oxacillin
cloxacillin
nafcillin
differentiate between the structure of penicillins vs cephalosporins
both have 4-membered beta lactam ring
however, in penicillins, the fused ring is a 5-membered thiazoline and in cephalosporins it is a 6-membered dihydrothiazine ring
also, penicillins have 1 R substituent and cephalosporins have 2
differentiate between the resistance to B lactamases between penicillins and cephalosporins
cephalosporins are MORE RESISTANT to beta lactamases
(but, some strains e coli and klebsiella that have extended spectrum b lactamases can still break cephalosporins)
which have broader spectrum - penicillins or cephalosporins
cephalosporins
cephalosporins, tho they have broader spectrum than penicillins, are STILL not active against __ and ____
listeria and enterococci
true or false
cephalosporins have similar MOA and resistance mechanisms as penicillins
true
how many cephalosporin generations are there??
explain the trends as far as:
-gram positive activity
-gram negative activity
-B lactamase resistance
5 generations
-all have similar activity against gram positive
-as you move up the generations (1–>5) there is a broader spectrum and more activity against gram (-)
-as you move up the generations (1–>5) B lactamase resistance increases
name 3 1st gen cephalosporins
cephalexin
cefadroxil
cefazolin
how can you remember which cephalosporins are 3rd gen
“one”
“ten”
“ime”
and cefdinir
4th gen cephalosporin
cefepime
2 5th gen cephalosporins
ceftaroline
ceftolozane
cefprozil and cefuroxime - what gen
2nd gen
3 mechanisms of cephalosporin resistance
-decreased concentration at site of action
-alter TWO PBP’s (1A and 2X)
-hydrolyzed by b lactamases (cephalosporinases)
when the two PBP’s are altered, it makes ____ resistant to ______
pneumococci resistant to 3RD GEN CEPHALOSPORINS
First gen cephalosporins have HIGH ACTIVITY against
gram positive cocci
(streptococci and staphylococci)
what can 1st gen cephalosporins NOT be used to fight
MRSA
pseudomonas
enterobacter, citrobacter
how is cephalexin administered
orally
how is cefazolin administered
IV infusion only
how are 1st gen cephalosporins eliminated
RENALLY - MUST DC DOSE
same issue as penicillins w seizures
same DDI for 1st gen ceph and penicillins
probenecid substantially increases serum levels
cephalexin clinical uses
PO 1st gen cephalosporin
UTI, staph and strp infections like cellulitis or soft tissue abscess
NOT FOR SERIOUS SYSTEMIC INFECTIONS
at which gen can cephalosporins start being used for respiratory infections including pneumonia
2nd gen
2nd gen have high activity against what 2 bacteria
Klebsiella and H. influenzae
-cause respiratory infection!!
gram positive cocci
true or false
similar to 1st gen, 2nd gen cephalosporins are not active against enterococci, pseudomonas, or enterobacter infections
TRUE
true or false
cefuroxime is a 1st gen cephalosporin
FALSE - 2nd gen
how is cefuroxime administered
can be oral (cefuroxime axetil) or parenteral by IV (cefuroxime)
how is cefproxil administered and what gen
2nd gen oral
most cephalosporins are ________ cleared and thus require…..
renally cleared and thus require dose adjustment in renal failure
major gen of cephalosporins used for meningitis
3rd gen
which particular 2nd gen is used in CAP
cefuroxime
ORAL cephalosporins 2nd gen clinical uses
lower resp tract infections
sinusitis
otitis
true or false
3rd gen cephalosporins CANNOT be used in enterobacter infections
TRUE
4th gen can
main clinical uses 3rd gen cephalosporins
meningitis
sepsis
serious infections
3rd gen cephalosporins have high activity against which 2 bacteria
haemophilus
neisseria
(both can cause meningitis)
true or false
2nd gen cephalosporins can be used for CAP
true – specifically cefuroxime
true or false
3rd gen have high activity against citrobacter
true
which 3rd gen cephalosporin is NOT renally eliminated and thus does NOT require a dosage adjustment in renal failure
ceftriaxone
removed by liver (biliary tract)
intramuscular __ + ___ is used to treat gonorrhea
ceftriaxone + azithro
true or false
2nd gen cephalosporins can be used for the treatment of sepsis
FALSE
3rd gen
ceftazidime generation
3rd gen (one/ime/ten)
_____ + _______ is used to treat neutropenic and febrile immunocompromised patients
ceftazidime + avibactam (b lactamase inhibitor
ceftazidime = 3rd gen cephalosporin - used for serious infections!
name 2 cephamycins and what generation are they
part of 2nd gen
cefoxitin and cefotetan
the ORAL 2nd gen cephalosporins are active against __ and ___
b lactamase producing H. influenzae or moraxella catarrhalis
3rd gen cephalosporins have moderate activity against _____
specifically which 3rd gen
pseudomonas aeruginoisa
only ceftazidime
3rd gen cephalosporins distribute well in the ____, aside from _____
well in CSF, aside from ORAL 3rd gen cephalosporins
___ and ___ are approved for meningitis including meningitis caused be pneumococci, meningococci, H. influenzae, and susceptible enteric gram negative rods
ceftriaxone and cefotaxime
(3rd gen)
can 4th gen, like 3rd, also be used for febrile neutropenia empiric therapy?
yes
name 4 bacteria that cefepime has good activity against
pseudomonas
enterobacteriaceae
staph aureus (NOT MRSA)
streptococccal pneumonia
4TH GEN
true or false
cefepime is only given by IV route
true
2 main clinical uses of cefepime
enterobacter infections
empiric therapy of febrile neutropenia
good for nosocomial infections!
how is it that 4th gen cephalosporin like cefepime has good activity against enterobacter
it’s more resistant to the beta lactamases produced by them
TRUE OR FALSE
ceftaroline fosamil is not active against MRSA
FALSE - it is
2 major clinical uses ceftaroline fosamil
CAP
SSTI (MRSA)
ceftaroline fosamil is NOT active against —
extended spectrum b lactamase producing organisms or ampc
true or false
ceftaroline fosamil is a prodrug
true
metabolized to ceftaroline
TRUE OR FALSE
ceftaroline fosamil retains binding to PBP2a
TRUE - ACTIVE AGAINST MRSA!
true or false
ceftaroline fosamil is susceptible to chromosomal b lactamases
true
name 2 cephalosporins that can be combined with a b lactamase inhibitor
also name their class
ceftazidime (3rd gen) + avibactam
ceftolozane (5th gen) + taxobactam
could also add metronidazole to that
with is the clinical use of ceftolozane + tazobactam + potential metronidazole
for hospital acquired pneumonia
complicated UTI
abdominal infections
true or false
ceftolozane is not renally excreted
false - it is - need dose adjustment
what is approximate chance of cross reactivity that someone allergic to penicillin will also be allergic to cephalosporins?
which gens is this most likely for?
~1%
more likely with 1st and 2nd gen cephalosporins
main toxicity of cephalosporins
RENAL toxicity - interstitial nephritis and tubular necrosis
which group can cause bleeding issues and what molecule is it on
what is done to resolve
MTT - methylthiotetrazole on cefotetan (2nd gen cephamycin)
given with vitamin K
gives severe disulfuram like reactions and hypoprothombinemia and bleeding disorders
true or false
cephalosporins can cause c diff diarrhea
true - bc kills normal flora and c diff can overgrow
cephalosporins can cause ___ penia and ______penia
leukopenia and thrombocytopenia
decreased blood cell count
*what generation of cephalosporins are recommended for the treatment of bacterial meningitis
3rd gen
