cephalosporins

Question 1

what is their spectrum of activity

Answer 1

broad spectrum

Question 2

state some uses of cephalosporins

Answer 2

septicaemia
pnuemonia
meningitis
biliary tract infections
peritonitis
UTI

Question 3

they are mainly excreted…

Answer 3

renally

Question 4

the pharmacology is similar to this class of abx

Answer 4

penicillin’s

Question 5

can they penetrate the CSF

Answer 5

poorly unless meninges are inflamed

Question 6

name the 2 cephalosporins that are suitable for infections of CNS e.g. meningitis

Answer 6

cefotaxime
ceftriaxone

Question 7

principal side effect of cephalosporins …

Answer 7

hypersensitivity

Question 8

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

Answer 8

cefotaxime
cefixime
ceftazidime
ceftriaxone
cefuroxime

Question 9

which ones are more likely to cause CDI

Answer 9

CDI: BS penicillins, cephalosporins (esp 3 and 4 gen), clindamycin, fluoroquinolones

Question 10

which cephalosporins must you avoid in pt with history of immediate hypersensitivity to penicillin

Answer 10

cefaclor, cefadroxil, cefalexin, cefradine, and ceftaroline fosamil

Question 11

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?

Answer 11

cefalexin

Question 12

cefalexin is a ….gen cephalorpsorin

Answer 12

1st gen

Question 13

cefuroxime is a …. gen cephalosporin

Answer 13

2nd gen

Question 14

cefixime, cefotaxime, ceftazidime and ceftriaxone are … gen cephalosporin

Answer 14

3rd gen

Question 15

cefixime, cefotaxime, ceftazidime and ceftriaxone are 3rd gen cephalosporins. their broad spectrum may encourage…

Answer 15

superinfection with resistant bacteria or fungi

Question 16

dose and half life of ceftriaxone

Answer 16

long half life, dose OD

Question 17

which second gen cephalosporin is less susceptible than the earlier cephalosporins to inactivation by beta lactamases?

Answer 17

cefuroxime

Question 18

MOA cephalosporins

Answer 18

attach to penicillin binding proteins to interrupt cell wall synthesis
leads to bacterial cell lysis and death

bactericidal

Question 19

can ceftriaxone be given orally

Answer 19

no given IV IM etc

Question 20

cephalosporins are …. toxic so interactions include drugs that are also …toxic

Answer 20

nephrotoxic

Question 21

interactions of ceftriaxone - vit K antagonists and calciums

Answer 21

• acenocoumarol, warfarin, pheninidone - increased risk of bleeding events
• calcium - IV ceftriaxone increases risk of cardio-respiratory arrest when given with IV calcium. avoid.

Question 22

what can the calcium salt of cetriaxone do?

Answer 22

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

Question 23

can you give a cephalosporin to someone with immediate hypersensitivity to penicillin and other beta lactams

Answer 23

no

Question 24

monitoring requirements of ceftriaxone

Answer 24

FBC regularly during prolonged treatment

Question 25

can cefotaxime be given orally

Answer 25

no it is given IV,IM etc

Question 26

can cefixime be given orally

Answer 26

yes it is only given orally

Question 27

name some nephrotoxic drugs - so increased risk when given with cephalosporins

Answer 27

• aciclovir
• aspirin
• amphotericin B
• NSAIDs
• ACEi
• -platins
• lithium
• methotrexate
• sulfasalazine
• trimethoprim
• zolendronate
• vancomycin

Question 28

what is the dose of cefalexin for lower UTI in pregnancy

Answer 28

500mg BD for 7 days

Question 29

are they hepatotoxic or nephrotoxic

Answer 29

nephrotoxic