Cephalosporins

Question 1

Are cephalosporins classified by structure or activity? Why?

Answer 1

Activity because structure is not related to activity

Question 2

Name the 1st generation cephalosporins

Answer 2

Cefadroxil, Cephalexin, Cefapirin, Cefazolin

Question 3

What is the spectrum of the first generation cephalosporins?

Answer 3

Mostly Gram +

Little gram -

Question 4

How are the second generation CPs different from first generation?

Answer 4

Similar gram +
More gram -
Less activity againt Strep & staph
More activity against enterobacteriaceae

Question 5

What are the third generation cephalosporins?

Answer 5

Cefpodoxime proxetil, cefotaxime, ceftazidine, ceftiofur Na, ceftiofur hydrochloride, Ceftiofur crystalline free acid, Cefovecin

Question 6

What is the spectrum of third generation cephalosporins?

Answer 6

Much more gram -

Similar gram +

Question 7

Which third generation cephalosporin is best for anaerobes?

Answer 7

Cefatoaxime

Question 8

Which third generation cephalosporin is best for Pseudomonas?

Answer 8

Ceftazidime

Question 9

Which third generation cephalosporin has the longest half-life?

Answer 9

Ceftriaxone

Question 10

Name the fourth generation cephalosporin

Answer 10

Cefepime

Question 11

Fourth generation cephalosporins were formed to overcome resistance by which bacteria?

Answer 11

Pseudomonas

Enterobacteriaceae

Question 12

Which first generation cephalosproin has the best activity against gram -?

Answer 12

Cefazolin

Question 13

What is the revised spectrum for 1st and 2nd generations?

Answer 13

Anerobes: +++++
Gram + Aerboes: +++++
Gram - aerobes: ++

Question 14

What is the revised spectrum for 3rd generation?

Answer 14

Anaerobes: ++
Gram + Aerobes: ++
Gram - aerobes: +++++

Question 15

Can you use ceftiofur for staph?

Answer 15

No

Question 16

Would a staph that is methicillin resistant be resistant to 4th generation cephalosporins?

Answer 16

No

Question 17

What is the revised spectrum for 4th generation cephalosporins?

Answer 17

Aerobes: +++++
Anaerobic Gram +: ++
Anaerobic gram -: none

Question 18

Which bacteria are the main target of fourth generation cephalosporins?

Answer 18

Enterobacteriaceae

Question 19

Are cephalosporins water soluble?

Answer 19

Very

Poor lipid solubility

Question 20

What is the efficacy of cephalosporin most connected to?

Answer 20

Time above MIC in plasma

Question 21

Are cephalosporins bactericidal or -static?

Answer 21

Bactericidal

Question 22

What generation is cefovecin?

Answer 22

Third

Question 23

Why does cefovecin have such a long half-life? What is this half-life?

Answer 23

High protein binding
133 hrs in dogs
166 hrs cats

Question 24

Following a single administration of cefovecin in a dog, how long is there activity against Staph intermedius? Pasteurella multocida?

Answer 24

7 days against S. intermedius

14 days against P. multocida

Question 25

What is the concern when administering Cefovecin concurrently with carprofen, furosemide, doxycycline, ketoconazole?

Answer 25

Competitive protein binding & increase free concentrations of these drugs

Question 26

Does Cefovecin reach the MIC90 for E. coli, pseudomonas, enterococci?

Answer 26

No

Question 27

What are the indications for Naxcel (Ceftiofur Na) in cattle?

Answer 27

IM, SQ for BRD | Footrot (F. necrophorum, B. melaninogenicus

Question 28

What are the indications for Naxcel (Ceftiofur Na) in swine?

Answer 28

IM for swine bacterial pneumonia (Actinobaciullus pleuropneumonia, P. multocida, S. cholerasuis, S. suis)

Question 29

What are the indications for Naxcel (ceftiofur Na) in sheep?

Answer 29

IM | Sheep respiratory dz (P. haemolytica, P. multocida)

Question 30

What are the indications for Naxcel (ceftiofur nA) in Goats?

Answer 30

IM | Caprine respiratory dz (P. haemolytica & multocida)

Question 31

What are the indications for Naxcel (ceftiofur Na) in horses?

Answer 31

IM | Respiratory infections with S. zooepidemicus

Question 32

What are the indications of Naxcel (Ceftiofur Na) in dogs?

Answer 32

SQ | UTI from E. coli or P. mirabilis

Question 33

What are the indications of Naxcel (Ceftiofur Na) in day old chickens?

Answer 33

SQ | Control early mortality associated with E. coli

Question 34

What are the indications of Naxcel (Ceftiofur Na) in day old turkey poults?

Answer 34

SQ | Control of early mortality associated with E. coli

Question 35

Can you use Naxcel (Ceftiofur Na) in lactating dairy cattle/sheep/goats?

Answer 35

Yes

Question 36

Compare and contrast IM vs IV injection of Ceftiofur in cattle

Answer 36

Cmax IM is 4 vs IV 7 Tmax IM is .75 vs IV .3 T1/2 is similar

Question 37

What is the MIC90 for Salmonella & E. coli in swine/cattle?

Answer 37

1.0 ug/mL

Question 38

Why is Ceftiofur hydrochloride (excenel) considered RTU and Ceftiofur Na is not?

Answer 38

Ceftiofur hydrochloride comes in cottonseed oil suspension, Ceftiofur Na is sterile powder

Question 39

Are indications between Ceftiofur Na and Ceftiofur hydrochloride very different?

Answer 39

No. still primarily respiratory disease & footrot | Excenel also for metritis

Question 40

Are the Cmax & T1/2 similar between IM Naxcel and SQ/IM Excenel?

Answer 40

Yes. There is no reason to use IM Ceftiofur

Question 41

Where is Ceftiofur CFA (Excede) labeled for injection use in cattle?

Answer 41

SQ under skin of ear and at base of ear

Question 42

Why do you never inject Excede SQ in the neck of cattle?

Answer 42

Drastically extended slaughter withdrawal time

Question 43

What are the indications of using CCFA (Excede) in cattle?

Answer 43

SQ in ear | BRD & for prophylaxis of BRD

Question 44

What are the indications in swine for Excede? (CCFA)

Answer 44

IM in neck | Respiratory disease

Question 45

What are the indications for Excede (CCFA) in horses?

Answer 45

SQ in ear | Lower respiratory infections (S. zooepidemicus)

Question 46

What is the half-life of an SQ injection of excede in the ear of cattle?

Answer 46

62 hours

Question 47

What is the half-life of IM injection of Excede (CCFA) in neck of swine?

Answer 47

49 hours

Question 48

What is the indication for Simplicef (Cefpodoxime proxetil)?

Answer 48

Oral tablets for dogs with skin infections by S. intermedius, S. aureus, Streptococcus canis, E. coli, P. multocida, P. mirabilis

Question 49

Does Simplicef (Cefpodoxime proxetil) work against Pseudomonas?

Answer 49

No

Question 50

What is the half-life of Simplicef (Cefpodoxime proxetil) in dogs?

Answer 50

5 hours

Question 51

Which strains of Salmonella are resistant to cephalosporins? Which animal species are these linked to?

Answer 51

``` Salmonella Heidelberg (poultry) Salmonella Newport & Salmonella typhimurium in dairy cattle ```

Question 52

Which cephalosporins can reach therapeutic levels in the CNS of humans?

Answer 52

Ceftazidine, Ceftriaxone, Cefipime, Cefotaxime

Question 53

Which cephalosporins have CLSI approved veterinary breakpoints?

Answer 53

Ceftiofur, cefpodoxime

Question 54

What is ceftiofur rapidly metabolized to? Are these compounds equipotent?

Answer 54

desfuroylceftiofur. Yes except for staph (MIC90 for ceftiofur is 1 ug/mL, MIC90 for desfuroylceftiofur is 4 ug/mL)

Question 55

Is there cross-reactivity between penicillins and cephalosporins in veterinary species?

Answer 55

Unknown but estimated at 15% in humans

Question 56

What is the main organ to which cephalosporins are most toxic?

Answer 56

Kidney (nephrotoxicity)

Question 57

Can you use cephalosporins in a healthy patient? CKD patient?

Answer 57

Yes | No

Question 58

Which other class of antibiotics may increase nephrotoxicity of cephalosporins if administered concurrently?

Answer 58

Aminoglycosides

Question 59

Very high doses or prolonged doses of cephalosporin can lead to complications with what system?

Answer 59

Immune system | Hepatitis, agranulocytosis, thrombocytopenia

Question 60

Administration of oral cephalosporins can lead to what?

Answer 60

Anorexia, vomiting, diarrhea

Question 61

What issues are we concerned with in horses & cephalosporins? Which administration route are we most worried?

Answer 61

Clostridium difficile enterocolitis with equine diarrhea especially if given IV

Question 62

Is Ceftiofur Na labeled for IV administration in horses?

Answer 62

No, IM

Question 63

If a dog is well titrated on phenobarbital, what is the issue with administration of cephalosporin?

Answer 63

Cephalexin will decrease seizure threshold

Question 64

Can you use cephalosporins extra-label in food animals?

Answer 64

Only if route, duration, dose and everything else is followed (revoked 2012) and NO HUMAN CEPHALOSPORINS