Cephalosporins

Question 1

1st generation drugs

Answer 1

G+ mainly including B-L resistant
Weak against G-
Ex: Cephazolin and cephalexin

Question 2

2nd generation drugs

Answer 2

Reduced activity against G+ (Anaerobes)
↑ activity against G- (E. coli)
Ex: Cefoxitin

Question 3

3rd generation drugs

Answer 3

Staph +, Strept ++, enterobacter +++
Antipseudomonal (Cefoperazone and ceftazidine)
B-L resistant
For meningitis causes by G- bacteria in small animals

Question 4

Examples of 3rd generation drugs

Answer 4

Ceftiofur, cefovecin, cefotaxime,cefpodoxime, ceftazidime

Question 5

Cephalexin

Answer 5

Staph pyoderma, UTI in dogs
Dermal and UTIs in cats
Respiratory infections in horses

Question 6

Cefazolin

Answer 6

Gram- , better against E. coli
Avoid during sx because of surgical prophylaxis (resistance,destory natural bacteria)

Question 7

Cefazolin uses

Answer 7

Dogs: surgical prophylaxis, bone infections, orthopedic sx
Horses: Pre-op or peri-op, bone infections

Question 8

Cefoxitin

Answer 8

Good anaerobic spectrum (bacteroides group)
Uses: organisms resistant to 1st gen cephalos

Question 9

Ceftiofur

Answer 9

Dogs: UTI
Horse: resp tract infections, neonatal sepsis
Cattle/pigs: Shipping fever, resp. diseases

Question 10

Cefovecin (convenia)

Answer 10

UTI and soft tissue infections in dogs and cats
Skin and periodontal infections
Good for Staph intermedius and Strept canis

Question 11

Cefpodoxime proxetil

Answer 11

Pyoderma in dogs

Question 12

Cefotaxime

Answer 12

Enteric gram- bacteria and strept in dogs and cats

Question 13

Which cephalosporin has the longest half-life?

Answer 13

cefovecin (130h because of high protein binding)

Question 14

Adverse effects of cephalosporins

Answer 14

Pseudomembranous enterocolitis (if high biliary excretion)
Hypersensitivity rx
Hemolytic anemia

Question 15

What do high doses of ceftiofur cause in dogs?

Answer 15

Thrombocytopenia: interferes with platelet function and compete with vitamin K

Question 16

Irritants caused by cephalosporins (local and GI)

Answer 16

Pain injection sites
Irritant GI and inhibit normal microflora (V/D)
Don’t administer intrathecally
Risk of phlebitis

Question 17

Special species considerations

Answer 17

Reptiles: slow excretion
Birds: rapid elimination and poor oral absorption with high does and frequent admin

Question 18

3rd generation cephalosporins are very susceptible to

Answer 18

Extended spectrum beta lacatamases (ESBL)

Question 19

Imipenem (carbapenems/ reserved drugs)

Answer 19

Potentially toxic unless combined with cilastatin
Wide distribution (CNS- meningitis)
Crosses placenta and excreted in milk

Question 20

Imipenem uses

Answer 20

Wide G- (cocci and rods) and G+ (anaerobic and aerobic)
Resistance B-L
Can cause seizures

Question 21

Aztreonam (monobactams/ reserved drugs)

Answer 21

Narrow spectrum, G- aerobic
B-L resistant
Patients allergic to B-L may not be allergic to this

Question 22

Vancomycin (reserved drug)

Answer 22

Glycopeptide, bactericidal
G+ (cocci)
Used for systemic and GI infections, MRSA in small animals, pseudomembranous enterocolotis

Question 23

Adverse affects of vancomycin

Answer 23

Rapid IV injection and lead to histamine release → hypotension (red neck)
Thrombophlebitis and nephrotoxicity

Question 24

Bacitracin

Answer 24

Cyclic poly peptide, bactericidal
Used per os
G+ bacteria

Question 25

Bacitracin uses

Answer 25

Skin and mucous membranes
Prevents and treats enteritis caused by P. perfrigens in pigs
Necrotic enteritis in poultry
Growth promotor in poultry, swine and cattle

Question 26

Polymixins

Answer 26

Polypeptide
Bactericidal: disrupts cell mem of phospholipids and↑ in cell permeability of G- bacteria
Highly nephrotoxic

Question 27

Polymixins uses

Answer 27

G- bacteria
Topical only and orally in GI tract (polymixin)
G- enteric infection in swine and cattle (colistin)