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

Answer 9

cefaclor, cefadroxil, cefalexin, cefradine, and ceftaroline fosamil

Question 10

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 10

cefalexin

Question 11

cefalexin is a ….gen cephalorpsorin

Answer 11

1st gen

Question 12

cefuroxime is a …. gen cephalosporin

Answer 12

2nd gen

Question 13

cefixime, cefotaxime, ceftazidime and ceftriaxone are … gen cephalosporin

Answer 13

3rd gen

Question 14

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

Answer 14

superinfection with resistant bacteria or fungi

Question 15

dose and half life of ceftriaxone

Answer 15

long half life, dose OD

Question 16

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

Answer 16

cefuroxime

Question 17

MOA cephalosporins

Answer 17

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

Question 18

can ceftriaxone be given orally

Answer 18

no given IV IM etc

Question 19

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

Answer 19

nephrotoxic

Question 20

interactions of ceftriaxone - vit K antagonists and calciums

Answer 20

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

Question 21

what can the calcium salt of cetriaxone do?

Answer 21

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 22

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

Answer 22

no

Question 23

monitoring requirements of ceftriaxone

Answer 23

FBC regularly during prolonged treatment

Question 24

can cefotaxime be given orally

Answer 24

no it is given IV,IM etc

Question 25

can cefixime be given orally

Answer 25

yes it is only given orally

Question 26

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

Answer 26

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

Question 27

what is the dose of cefalexin for lower UTI in pregnancy

Answer 27

500mg BD for 7 days