AB - Cephalosporins, tetracyclines, metronidazole

Question 1

What class of antibiotics are cephalosporins?

Answer 1

Beta-lactams

Question 2

Are cephalosporins bacteriostatic or bactericidal?

Answer 2

Bactericidal

Question 3

Cephalosporins are _______ dependent

Answer 3

Time

Question 4

Cephalosporins are generally not effective against __________

Answer 4

Anaerobes

Question 5

Cephalosporins are __________ bactericidal than penicillins

Answer 5

Less

Question 6

Which drugs often require frequent administration, penicillins or cephalosporins?

Answer 6

Cephalosporins (especially 1st and 2nd generation)

Question 7

What tissues do cephalosporins not penetrate?

Answer 7

Cephalosporins do not enter the CNS, prostate, or intracellular space

Question 8

True or False: Cephalosporins are excreted unchanged through the kidney

Answer 8

True, they are probably the best drug for UTIs

Question 9

What are the first generation cephalosporins?

Answer 9

Cefazolin and cephalexin

Question 10

First generation cephalosporins are a category _______ drug

Answer 10

2

Question 11

What condition is cephalexin commonly used to treat?

Answer 11

Staphylococcal pyoderma in dogs

Question 12

How can cephalexin be administered?

Answer 12

Only orally

Question 13

How can cefazolin be administered?

Answer 13

IV, IM, or SQ

Question 14

What condition is cefazolin commonly used to treat?

Answer 14

It is commonly used as perioperative prophylactic antibacterial in companion animals

Question 15

What are the second generation cephalosporins?

Answer 15

Cefoxitin

Question 16

Describe the spectrum of second generation cephalosporins compared to first generation cephalosporins

Answer 16

The spectrum of second generation cephalosporins is similar to that of first-generation cephalosporins, but they have some activity against anaerobes (especially Bacteroides)

Question 17

Second generation cephalosporins are a category _______ drug

Answer 17

2

Question 18

What are the third generation cephalosporins?

Answer 18

Ceftiofur and cefovecin

Question 19

Ceftiofur is approved for ______________ in dogs

Answer 19

UTIs

Question 20

What drug has the trade name Convenia?

Answer 20

Cefovecin

Question 21

What is a major drug contraindication you need to be wary of when prescribing cefovecin and why?

Answer 21

It is highly protein bound (99%+) so it may displace other protein bound drugs (do not use with NSAIDs)

Question 22

How long does cefovecin maintain therapeutic concentrations against bacteria?

Answer 22

It maintains therapeutic concentrations against some bacteria for up to 14 days (for example, a single subcutaneous injection provides levels above the MIC for 1 - 2 weeks!!)

Question 23

Describe the spectrum of cefovecin

Answer 23

It is broader-spectrum than 1st generation cephalosporins, but not as active against Gram-negatives as other 3rd generation drugs

Question 24

Third generation cephalosporins are a category _______ drug

Answer 24

1 (do not use unless absolutely necessary)

Question 25

Describe the spectrum of third generation cephalosporins compared to second generation cephalosporins

Answer 25

Third-generation cephalosporins have greater activity against Gram-negative pathogens than the earlier generations

Question 26

Which cephalosporin is the most commonly used in veterinary medicine?

Answer 26

Cephalexin

Question 27

Which beta-lactam class has the broadest anti-microbial spectrum?

Answer 27

Carbapenems (therefore reserve these for very severe, resistant infections)

Question 28

Name the two carbapenems

Answer 28

Imipenem and meropenem

Question 29

Which beta-lactam class is the most bactericidal?

Answer 29

Carbapenems

Question 30

What class of antibiotics are tetracyclines?

Answer 30

Protein synthesis inhibitors

Question 31

Are tetracyclines bacteriostatic or bactericidal?

Answer 31

Bacteriostatic

Question 32

Tetracyclines are _______ dependent

Answer 32

Time

Question 33

Which bacteria are tetracyclines effective against?

Answer 33

Gram-positive aerobes, Gram-positive anaerobes, Gram-negative anaerobes (basically everything except certain enteric Gram-negative aerobes like E. coli)

Question 34

What are the main adverse effects of tetracyclines?

Answer 34

- Hypotension and collapse after rapid IV administration (may decrease calcium availability to the heart) **administer SLOWLY IV or give in diluted fluids** - Teeth discoloration - Inhibited long bone growth in young animals - Crosses placenta

Question 35

Tetracyclines are a category ________ drug

Answer 35

3

Question 36

What are the two main tetracyclines?

Answer 36

Doxycycline and oxytetracycline

Question 37

Which is more highly absorbable and lipophilic, doxycycline or oxytetracycline?

Answer 37

Doxycycline

Question 38

Oxytetracycline is primarily eliminated by which organ?

Answer 38

Kidneys

Question 39

Doxycycline is primarily eliminated by which organ?

Answer 39

The GI tract

Question 40

What is oxytetracycline commonly used to treat?

Answer 40

Pneumonia/respiratory disease, mastitis, Potomac horse fever (Neorickettsia risticii), metritis, and tendon contracture (in large animals)

Question 41

What is doxycycline commonly used to treat?

Answer 41

Vector-borne intracellular pathogens (small animals)

Question 42

What are some examples of diseases that are treated with doxycycline?

Answer 42

Tick-borne diseases (Ehrlichia canis, Borrelia burgdorferi, Rickettsia), Mycoplasma haemofelis, feline chronic rhinitis, heartworm in dogs

Question 43

What are the main adverse effects of doxycycline?

Answer 43

- Oral form can cause esophageal strictures in cats (always follow with water - never give dry) - Never give IV to horses (death)

Question 44

What condition is doxycycline not good for and why?

Answer 44

Not good for UTIs since it's excreted in the feces (but on the upside it doesn't accumulate in patients with renal failure)

Question 45

Why is doxycycline used in the treatment of heartworm disease?

Answer 45

Treating dogs with heartworm with doxycycline kills the Wolbachia organisms within the heartworms. These organisms have a symbiotic relationship with the heartworms, and if they are eliminated it facilitates heartworm elimination and leads to better outcomes.

Question 46

What are the anti-inflammatory effects of doxycycline?

Answer 46

Doxycycline inhibits matrix metalloproteinase activity, neutrophil activation, and T-cell proliferation

Question 47

What inflammatory condition is doxycycline often used to treat?

Answer 47

Feline chronic rhinitis

Question 48

What class of antibiotics are nitroimidazoles?

Answer 48

DNA disruptors (produce short-lived free radicals that damage bacterial DNA)

Question 49

What is the most common nitroimidazole used in veterinary medicine?

Answer 49

Metronidazole

Question 50

Are nitroimidazoles bacteriostatic or bactericidal?

Answer 50

Bactericidal

Question 51

Nitroimidazoles are _______ dependent

Answer 51

Concentration

Question 52

Describe the spectrum of activity of nitroimidazoles

Answer 52

Effective against anaerobes and protozoans

Question 53

Which main conditions is metronidazole used to treat?

Answer 53

Giardiasis and gut inflammation

Question 54

Why can't metronidazole be used in production animals?

Answer 54

It is a teratogen and a potential carcinogen