C.9. Cephalosporins

Question 1

how are cephalosporins given?

Answer 1

parenteral only

cephalexin and cefixime are available orally

Question 2

how many generations of cephalosporins do we have?

Answer 2

5

Question 3

which generations of cephalosporins can cross the BBB?

Answer 3

3rd and 4th

Question 4

which generations of cephalosporins do not enter the CNS?

Answer 4

1st and 2nd

Question 5

half-life (T1/2) of cephalosporins

Answer 5

1.5 h’ (given every 8h’)

Question 6

what drugs are more stable-penicillins or cephalosporins?

Answer 6

cephalosporins

Question 7

what organisms are not covered by 1-4 gen’ cephalosporins?

Answer 7

‘LAME’

Listeria
Atypicals (chlamydia, mycoplasma)
MRSA
Enterococci

Question 8

metabolism of cephalosporins

Answer 8

renal excretion, blocked by probenecid

biliary clearance–> ceftriaxone

Question 9

what is the mechanism of action and resistance of cephalosporin

Answer 9

similar to peniciliin

Question 10

what generation do cefazolin and cephalexin belong to?

Answer 10

1st

Question 11

spectrum and clinical uses of cefazolin and cephalexin (3)

Answer 11

1. gram + cocci (staph, strep)
2. UTI’s caused by gram - (proteus, E.coli, Klebsiella)
3. surgical prophylaxis (IV cefazolin)

Question 12

side effects of cephalosporins

Answer 12

1. hypersensitivity/ allergic reaction
2. vitamin K deficiency
3. Disulfiram like reaction (when taken with alcohol)
4. cross allergenicity between cephalosporins and penicillins
5. pain at IM injection site
6. Phlebitis after IV injection
7. when given with aminoglycosides–> ↑ nephrotoxicity

Question 13

what side effects are less common with cephalosporins than with penicillins

Answer 13

dysbacteriosis

hypersensitivity reaction

Question 14

what side effects are less common with cephalosporins than with penicillins

Answer 14

dysbacteriosis

hypersensitivity reaction

Question 15

spectrum and clinical uses of 2nd generation cephalosporins (3)

Answer 15

1. similar activity as 1st but extended gram -
2. Bacteroides fragilis (cefotetan, cefoxitin)
3. sinus, ear, and respiratory infection caused by H. influenza, M. catarrhalis (cefuroxime)

Question 16

what is the CI of Ceftriaxone?

Answer 16

in newborns–> causes jaundice

Question 17

what is the 1st line drug for N.gonorrhoea?

Answer 17

Cefixime (single dose, IM injection)

Question 18

list the 3rd generation cephalosporins

Answer 18

ceftriaxone
cefotaxime
cefixime
ceftazidime

Question 19

half life of Ceftriaxone is..

Answer 19

long

*CI in new borns–> jaundice

Question 20

half life of Cefotaxime is..

Answer 20

short

can be given to newborns

Question 21

spectrum and clinical use of 3rd generation cephalosporins (12)

Answer 21

1. ↑ activity aganist gram -
2. empiric treatment of bacterial meningitis (N.meningitidis, H. influenza, S. pneumoniae)
3. empiric treatment of sepsis
4. community and hospital acquired pneumonia, including PRSP strains (ceftriaxone)
5. pseudomonas (ceftazidime)
6. B. fragilis, B. burgdorferi
7. N. gonorrhoea
8. endocarditis (S. viridans), HACEK group
9. otitis
10. severe UTI
11. cholecystitis
12. abdominal infections

Question 22

what generation of cephalosporins have the most indications?

Answer 22

3rd

Question 23

what does HACEK group stand for?

Answer 23

Haemophilus 
Actinobacillus 
Cardiobacterium
Eikenella
Kingella

Question 24

what is Cefepime?

Answer 24

4th generation cephalosporin

Question 25

what generation do Ceftaroline fosamil and Ceftolozane belong to?

Answer 25

5th

Question 26

clinical use of Ceftaroline fosamil and Ceftolozane+ tazobactam?

Answer 26

broad spectrum (including MRSA)
Complicated UTI's
abdominal infections

Question 27

clinical use of cefepime

Answer 27

broad spectrum, resistant to most beta lactamase
Enterobacter, Hemophilus, Neisseria
Pneumococci, Pseudomonas

Question 28

what drug ↑ serum concentration of cephalosporins

Answer 28

probenecid

blocks renal excretion