AMDs

Question 1

what is the MoA of Penicillins

Answer 1

inhibits cell wall synthesis

Question 2

What AMD inhibits cell wall synthesis?

Answer 2

penicillin
cephalosporin

Question 3

What AMD inhibits protein synthesis?

Answer 3

Aminoglycoside, Tetracycline, Macrolides

Question 4

what are the main adverse effects of penicillins (3)

Answer 4

1) decrease seizure threshold
2) can cause fatal colitis in hindgut fermenters if given orally
3) hypersensitivities (incl. contact hypersensitivity -> not given topically)

Question 5

what are the main PK features of penicillins (3)

Answer 5

1) penicillin G is not acid stable
2) amoxicillin has an oral bioavailability of 90%
3) excreted intact in the urine

Question 6

how should we be treating penicillins

Answer 6

1) Penicillin G and amoxicillin
2) Potentiated penicillins

Question 7

what is the general spectrum of Penicillin G

Answer 7

G+ aerobes, anaerobes

Question 8

what is the general spectrum of amoxicillin

Answer 8

G+ aerobes, anaerobes, some G- aerobes

Question 9

all penicillins end in

Answer 9

“cillin”

Question 10

do penicillins have a long or short half life

Answer 10

short (<2h)

Question 11

what is the Vd (high or low) of penicillins and why

Answer 11

low; they distribute to extracellular fluids well (not brain or prostate) but have poor penetration of cells

Question 12

if an animal is hypersensitive to penicillins they are also likely reactive to

Answer 12

cephalosporins

Question 13

what is the MoA of cephalosporins

Answer 13

inhibit cell wall synthesis

Question 14

what are the major adverse effects of cephalosporins

Answer 14

hypersensitivity; colitis in hindgut fermenters if given orally; reduce seizure threshold

Question 15

how should we use cephalosporins

Answer 15

first line: 1st gen
second line: 3rd gen

Question 16

what are the major PK features of cephalosporins

Answer 16

• most are not acid-stable
• some 3rd gen (cefotaxime) enter CNS readily
• not destroyed by penicillinases (may be destroyed by β-lactamases)

Question 17

what is the general spectrum of first generation cephalosporins

Answer 17

same as amoxicillin: G+ aerobes, anaerobes, some G- aerobes

Question 18

what is the issue with cefovecin (Convenia)

Answer 18

it is a third generation cephalosporin given as a single SQ injection with a 2-week half-life that essentially guarantees inappropriate duration of therapy

Question 19

what is a convenient (hint) AMD we should avoid using unless the patient is really aggressive or long duration of therapy needed

Answer 19

Cefovecin (Convenia)

Question 20

what are the main uses of aminoglycosides

Answer 20

1) topical infections (ex. staph)
2) serious G- aerobic systemic infections

Question 21

what is the MoA of aminoglycosides

Answer 21

inhibits protein synthesis; bactericidal

Question 22

what are the major adverse effects of aminoglycosides

Answer 22

nephrotoxicity and ototoxicity

Question 23

what are the major PK features of aminoglycosides

Answer 23

• highly ionized so no oral or topical absorption
• food residues are over 1y if given parenterally

Question 24

how should we give aminoglycosides

Answer 24

1st line: topical administration
2nd line: systemic administration

Question 25

what is the general spectrum of aminoglycosides

Answer 25

G- aerobes; mycoplasma; staph

Question 26

what is the MoA of tetracyclines

Answer 26

inhibit protein synthesis (bacteriostatic)

Question 27

what are the major adverse effects of tetracyclines

Answer 27

- nephrotoxicity if dehydrated - esophageal ulcers in cats - tissue irritation - incorporates into growing long bones and teeth

Question 28

what are the major PK features of tetracyclines

Answer 28

lipid soluble useful against intracellular pathogens

Question 29

how do we use tetracyclines and what is it especially important for

Answer 29

first line, especially important for atypical bacteria (mycoplasma, rickettsia, anaplasma, chlamydia...)

Question 30

what is a highly lipid soluble tetracycline

Answer 30

doxycycline

Question 31

what is the general spectrum of tetracycline in small animals? large animals?

Answer 31

small animals: atypical bacteria large animals: atypical bacteria plus some G+ and G- aerobes and anaerobes

Question 32

if giving tetracyclines what is an important feeding consideration

Answer 32

divalent cations in food (ex. calcium) will markedly decrease oral absorption

Question 33

what tetracycline has the best oral availability

Answer 33

doxycycline

Question 34

why is it a problem that tetracyclines will bind to multivalent cations (ex. calcium)

Answer 34

1) inhibits oral absorption if taken with calcium-containing foods 2) incorporates into growing long bones and teeth which creates food residues

Question 35

what is the MoA of sulphonamides

Answer 35

inhibit folic acid synthesis

Question 36

what are the main adverse effects of sulphonamides

Answer 36

- nephrotoxicity in dehydrated patients - hypersensitivity - lacrimotoxicity in dogs

Question 37

how should we use sulphonamides

Answer 37

first line!

Question 38

what are the main PK features of sulphonamides

Answer 38

inactive in the presence of pus; distributes to all tissues

Question 39

what is the general spectrum of sulphonamides for small animals and for large animals

Answer 39

small animals: UTIs, atypical bacteria large animals: fairly broad spectrum

Question 40

what does TMS stand for and what is it

Answer 40

trimethoprim sulfonamide; it is sulphonamide combined with a diaminopyrimidine inhibitor (trimethoprim) to help restore its effectiveness

Question 41

sulfonamides alone are ____________ whereas trimethoprim sulfonamides are _____________

Answer 41

bacteristatic; bactericidcal

Question 42

what is the MoA of macrolides

Answer 42

inhibit protein synthesis

Question 43

what are the main adverse effects of macrolides

Answer 43

- oral erythromycin causes nausea and vomiting - tissue irritation - potentially fatal colitis if given orally to hindgut fermenters

Question 44

how do we give macrolides

Answer 44

first line: erythromycin second line: newer macrolides

Question 45

what are some key PK features for macrolides

Answer 45

* erythromycin: inhibits P450 enzyme and stimulates motilin receptors * enters cells * concentrates in lungs * newer macrolides have long half lives

Question 46

in an animal with allergies what is better to give over penicillin

Answer 46

erythromycin (macrolid)

Question 47

macrolides are especially important for ________ disease

Answer 47

respiratory

Question 48

what AMD is fatal to swine and fatal in general if given IV

Answer 48

tilmicosin (a newer macrolide)

Question 49

what is the MoA of fluoroquinolones

Answer 49

inhibit DNA synthesis (DNA gyrases and topioisomerases)

Question 50

what are the main adverse effects of fluoroquinolones

Answer 50

- retinal damage in cats with enrofloxacin - decreased seizure threshold - cartilage damage

Question 51

how do we use fluoroquinolones

Answer 51

second line

Question 52

what are the main PK features of fluoroquinolones

Answer 52

- concentrates in lungs - most have a long half-life (not enrofloxacin) - oral absorption 100%

Question 53

what is the general spectrum of fluoroquinolones

Answer 53

similar to aminoglycosides.... staph, G- aerobes, atypicals

Question 54

what is the general spectrum of macrolides (old vs new)

Answer 54

old (erythromycin): some G- aerobes and some atypical; all G+ aerobes and anaerobes new: all G- aerobes; some G+ aerobes, anaerobes and atypical

Question 55

what drugs should we avoid using if at all possible (3)

Answer 55

fluoroquinolones, potentiated penicillins, 3rd gen cephalosporins

Question 56

how is chloramphenicol used in food animals and why?

Answer 56

Federal law banning the use chloramphenicol in food animal. Will cause aplastic anemia in humans!