cephalosporins Flashcards
what is their spectrum of activity
broad spectrum
state some uses of cephalosporins
septicaemia
pnuemonia
meningitis
biliary tract infections
peritonitis
UTI
they are mainly excreted…
renally
the pharmacology is similar to this class of abx
penicillin’s
can they penetrate the CSF
poorly unless meninges are inflamed
name the 2 cephalosporins that are suitable for infections of CNS e.g. meningitis
cefotaxime
ceftriaxone
principal side effect of cephalosporins …
hypersensitivity
f a cephalosporin is essential in patients with a history of immediate hypersensitivity to penicillin, because a suitable alternative antibacterial is not available, then the following FIVE cephalosporins can be used with caution
cefotaxime
cefixime
ceftazidime
ceftriaxone
cefuroxime
which ones are more likely to cause CDI
CDI: BS penicillins, cephalosporins (esp 3 and 4 gen), clindamycin, fluoroquinolones
which cephalosporins must you avoid in pt with history of immediate hypersensitivity to penicillin
cefaclor, cefadroxil, cefalexin, cefradine, and ceftaroline fosamil
this cephalosporin is commonly used in UTI infections, especially if the patient is pregnant, however it must be avoided in patients who have immediate hypersensitivity to penicillins. what is it?
cefalexin
cefalexin is a ….gen cephalorpsorin
1st gen
cefuroxime is a …. gen cephalosporin
2nd gen
cefixime, cefotaxime, ceftazidime and ceftriaxone are … gen cephalosporin
3rd gen
cefixime, cefotaxime, ceftazidime and ceftriaxone are 3rd gen cephalosporins. their broad spectrum may encourage…
superinfection with resistant bacteria or fungi
dose and half life of ceftriaxone
long half life, dose OD
which second gen cephalosporin is less susceptible than the earlier cephalosporins to inactivation by beta lactamases?
cefuroxime
MOA cephalosporins
attach to penicillin binding proteins to interrupt cell wall synthesis
leads to bacterial cell lysis and death
bactericidal
can ceftriaxone be given orally
no given IV IM etc
cephalosporins are …. toxic so interactions include drugs that are also …toxic
nephrotoxic
interactions of ceftriaxone - vit K antagonists and calciums
- acenocoumarol, warfarin, pheninidone - increased risk of bleeding events
- calcium - IV ceftriaxone increases risk of cardio-respiratory arrest when given with IV calcium. avoid.
what can the calcium salt of cetriaxone do?
it forms a precipitate in the gall bladder and urine
esp in young, dehydrated, immobilised
rarely this causes symptoms
consider stopping if symptomatic
will usually resolve on stopping abx
can you give a cephalosporin to someone with immediate hypersensitivity to penicillin and other beta lactams
no
monitoring requirements of ceftriaxone
FBC regularly during prolonged treatment
can cefotaxime be given orally
no it is given IV,IM etc
can cefixime be given orally
yes it is only given orally
name some nephrotoxic drugs - so increased risk when given with cephalosporins
- aciclovir
- aspirin
- amphotericin B
- NSAIDs
- ACEi
- -platins
- lithium
- methotrexate
- sulfasalazine
- trimethoprim
- zolendronate
- vancomycin
what is the dose of cefalexin for lower UTI in pregnancy
500mg BD for 7 days
are they hepatotoxic or nephrotoxic
nephrotoxic
