Antimicrobials 3

Question 1

MOA of cephalosporins?

Answer 1

they are beta lactams, they bind to penicillin binding proteins (PBPs) and inhibit peptidoglycan cross linking

Question 2

cephalosporins have a similar spectrum of action to _____

Answer 2

aminopenicilins
have some activity against beta lactamase producing strains and against some gram -s, but not very good for anaerobes

Question 3

list some PD and PK characteristics of cephalosporins

Answer 3

• bactericidal (less so than penicillins)
• time dependent
• freuent administrations
• excretion in urine (good for UTIs)
• few adverse effects

Question 4

name two practical uses of cephalosporin drugs

Answer 4

• prophylaxsis before surgery
• skin infections, staph

Question 5

what are the two first class cephalosporins I need to know

Answer 5

cephalexin (more common, oral admin), cefazolin (injectable)

Question 6

name clinical uses for cephalexin and cefazolin

Answer 6

cephalexin: staph pyoderma in dogs
cefazolin: periopperative prophylaxsis

Question 7

what are the two third gen cephalosporins i have to know?

Answer 7

ceftiofur and cefovecin

Question 8

third generation cephalosporins have greater activity against _____ pathogens than earlier generations

Answer 8

gram neg

Question 9

what kind of drug is ceftiofur and what is it commonly used for in vet med?

Answer 9

a 3rd gen cephalosporin, commonly used in horses and production animals, UTIs in dogs

cefitofur sodium is short acting, ceftiofur crystalline free acid is long acting

Question 10

what kind of drug is cefovecin, what is the brand name, and what is it used for commonly?

Answer 10

• a 3rd gen cephalosporin, very long acting and highly protein bound
• can be used for many many things, but DO NOT reach for it simply because of convienence

Question 11

MOA of tetracylines?

Answer 11

they are protein synthesis inhibitors, interferes with binding of tRNA to the ribosome, inhibiting bacterial protein synthesis

Question 12

list some PD and PK characteristics of tetracyclines

Answer 12

• bacteriostatic
• time dependent
• lipophilic (doxy moreso than oxy)
• quite variable in administration and excretion

Question 13

tatracyclines are good for what bacteria?

Answer 13

anything except for gram - aerobes like E coli

Question 14

what happens if you give tetracylines too fast IV?

Answer 14

hypotension and collapse, SO GIVE IT SLOWLY!!!

Question 15

what are the two big tatracyclines I need to remember?

Answer 15

doxycycline (companion animals) and oxytetracycline (production animals)

Question 16

list some clinical uses of oxytetracycline

Answer 16

• pneumonia and metritis in cattle/sheep/goats
• can be used for BRD in cattle
• potomac horse fever
• treat tendon contracture?

Question 17

you have a horse with potomac horse fever. what drug are you going to give and how will you give it?

Answer 17

oxytatracycline, given IV but diluted in a fluid bag to avoid CV effects

Question 18

what is some practical reasons to use doxycycline?

Answer 18

• for tick borne infections
• for mycoplasma
• chlamydia & resp infections

Question 19

the oral form of doxycycline can cause _____ in cats. For this reason, if you give it to a cat, you should…

Answer 19

esophageal strictures
do not give it dry, give water or food afterwards!

Question 20

which antimicrobial can be used as an add on treatment for heartworm in dogs? how does this work?

Answer 20

doxycycline. it kills the wolbachia organism in the worms, which helps the worms survive, so it makes the worms easier to kill

Question 21

not only does doxycycline have an antimicrobial effect, but it also has a _____

Answer 21

anti inflammatory effect!

Question 22

MOA of nitroimidazoles? what is the one drug in this class to remember?

Answer 22

produce short lived intermediates/free radicals inside bacteria/protozoans that damage their DNA

metronidazole

Question 23

list some general characteristics for metronidazole. what is it good at killing?

Answer 23

• bactericidal, concentration dependent
• kills anaerobes and protozoans

Question 24

which antimicrobial can be used to treat giardia in dogs?

Answer 24

metronidazole

Question 25

Why should you not use metronidazole in production animals?

Answer 25

it is potentially carcinogenic and teratogenic