C.9. Cephalosporins Flashcards
how are cephalosporins given?
parenteral only
cephalexin and cefixime are available orally
how many generations of cephalosporins do we have?
5
which generations of cephalosporins can cross the BBB?
3rd and 4th
which generations of cephalosporins do not enter the CNS?
1st and 2nd
half-life (T1/2) of cephalosporins
1.5 h’ (given every 8h’)
what drugs are more stable-penicillins or cephalosporins?
cephalosporins
what organisms are not covered by 1-4 gen’ cephalosporins?
‘LAME’
Listeria
Atypicals (chlamydia, mycoplasma)
MRSA
Enterococci
metabolism of cephalosporins
renal excretion, blocked by probenecid
biliary clearance–> ceftriaxone
what is the mechanism of action and resistance of cephalosporin
similar to peniciliin
what generation do cefazolin and cephalexin belong to?
1st
spectrum and clinical uses of cefazolin and cephalexin (3)
- gram + cocci (staph, strep)
- UTI’s caused by gram - (proteus, E.coli, Klebsiella)
- surgical prophylaxis (IV cefazolin)
side effects of cephalosporins
- hypersensitivity/ allergic reaction
- vitamin K deficiency
- Disulfiram like reaction (when taken with alcohol)
- cross allergenicity between cephalosporins and penicillins
- pain at IM injection site
- Phlebitis after IV injection
- when given with aminoglycosides–> ↑ nephrotoxicity
what side effects are less common with cephalosporins than with penicillins
dysbacteriosis
hypersensitivity reaction
what side effects are less common with cephalosporins than with penicillins
dysbacteriosis
hypersensitivity reaction
spectrum and clinical uses of 2nd generation cephalosporins (3)
- similar activity as 1st but extended gram -
- Bacteroides fragilis (cefotetan, cefoxitin)
- sinus, ear, and respiratory infection caused by H. influenza, M. catarrhalis (cefuroxime)
what is the CI of Ceftriaxone?
in newborns–> causes jaundice
what is the 1st line drug for N.gonorrhoea?
Cefixime (single dose, IM injection)
list the 3rd generation cephalosporins
ceftriaxone
cefotaxime
cefixime
ceftazidime
half life of Ceftriaxone is..
long
*CI in new borns–> jaundice
half life of Cefotaxime is..
short
can be given to newborns
spectrum and clinical use of 3rd generation cephalosporins (12)
- ↑ activity aganist gram -
- empiric treatment of bacterial meningitis (N.meningitidis, H. influenza, S. pneumoniae)
- empiric treatment of sepsis
- community and hospital acquired pneumonia, including PRSP strains (ceftriaxone)
- pseudomonas (ceftazidime)
- B. fragilis, B. burgdorferi
- N. gonorrhoea
- endocarditis (S. viridans), HACEK group
- otitis
- severe UTI
- cholecystitis
- abdominal infections
what generation of cephalosporins have the most indications?
3rd
what does HACEK group stand for?
Haemophilus Actinobacillus Cardiobacterium Eikenella Kingella
what is Cefepime?
4th generation cephalosporin
what generation do Ceftaroline fosamil and Ceftolozane belong to?
5th
clinical use of Ceftaroline fosamil and Ceftolozane+ tazobactam?
broad spectrum (including MRSA) Complicated UTI's abdominal infections
clinical use of cefepime
broad spectrum, resistant to most beta lactamase
Enterobacter, Hemophilus, Neisseria
Pneumococci, Pseudomonas
what drug ↑ serum concentration of cephalosporins
probenecid
blocks renal excretion
