Therapeutics for skin

Question 1

What are B-lactam antibiotics?

Answer 1

They inhibit bacterial growth by interfering with the transpeptidation of bacterial well synthesis

Question 2

When would you use B-lactam antibiotics for superficial pyoderma?

Answer 2

– Rx minimum of 3 weeks including
at least 7-10 days after resolution of clinical lesions

Question 3

When would you use B-lactam antibiotics for a deep pyoderma?

Answer 3

Rx at least 4-6 weeks including not less
than 2 weeks after resolution of clinical lesions

Question 4

What is the function of tetracyclines?

Answer 4

inhibit protein synthesis in susceptible bacteria –
bacteriostatic, time-dependent
* Foot rot in sheep and topical infections caused by organisms
sensitive to oxytetracycline in cattle, sheep and pigs

Question 5

What is the function of sulfonamides

Answer 5

Sulfonamides and dihydrofolate reductase
inhibitors (e.g. trimethoprim) interfere with the
production of folic acid and thereby purine
synthesis, usually combined (TMPS) - bactericidal,
time-dependen

Wound infections and open or drained abscesses in horses

Question 6

What is the function of Lincosamides?

Answer 6

• Inhibit protein synthesis
• clindamycin for treatment of infected wounds
  and abscesses and antimicrobial cover for dental
  procedures in dogs & cats

Question 7

What can you not administer to chinchillas, rabbits, hamsters, horses or ruminants

Answer 7

Lincosamide
because ingestion of
clindamycin by these species may result in severe gastrointestinal disturbance

Question 8

What is fusidic acid?

Answer 8

inhibits protein synthesis of bacteria -
bacteriostatic, high concentrations may be bactericidal.
Activity against Gram-positive bacteria, including
Staphylococcus spp

Question 9

What is polymyxin B?

Answer 9

binds to phospholipids in the bacterial
cytoplasmic membrane and disrupts the membrane -
bactericidal. Active against Gram-negative bacteria.

Question 10

What is the function of imidazoles?

Answer 10

inhibit ergosterol incorporation into cell membranes, cause increased
cell wall permeability and leakage of cellular contents

Question 11

What is the function of micanozole?

Answer 11

antifungal and has activity against yeasts

Question 12

What is the function of nystatin?

Answer 12

• broad spectrum antifungal, noted for its activity
  against Candida

Question 13

What is a triazole?

Answer 13

same mode of action to miconazole - itraconazole is
the systemic treatment of choice (cascade)

Question 14

What is the function of griseofulvin?

Answer 14

exact antifungal MoA uncertain - absorbed over a
prolonged period from the GI tract and deposited in keratin
precursor cells. Concentrates in stratum corneum, nail and in
hair thus preventing fungal invasion of newly forming cells.

Question 15

What is the function of a macrocytic lactone?

Answer 15

Opens glutamate

Question 16

What is Griseofulvin?

Answer 16

exact antifungal MoA uncertain - absorbed over a
prolonged period from the GI tract and deposited in keratin
precursor cells. Concentrates in stratum corneum, nail and in
hair thus preventing fungal invasion of newly forming cells.
- used to treat ringworm in horses

Question 17

What is Triazole?

Answer 17

same mode of action to miconazole - itraconazole is
the systemic treatment of choice (cascade)

Question 18

What does imidacloprid and nitenpyram belong to?

Answer 18

neonicotinoid group of insecticides. High affinity for post-synaptic nicotinic ACh receptors – results in paralysis and death of fleas & larvae

Question 19

What is the function of Pyrethyroids?

Answer 19

Pyrethroids (permethrin/cypermethrin/flumethrin) – many
mechanisms proposed - act on sodium channels causing
initial excitement then paralysis and death

Question 20

What is the function of amitraz?

Answer 20

formamidine insecticide/acaracide, octopamine
receptor agonist - increases nervous activity in synapses – rapid
detachment/death of parasites

Question 21

What is amitraz used to treat?

Answer 21

Used to treat mites, esp. demodicosis. Weekly wash until
2 negative skin scraps/hair plucks 2 weeks apart.
* Prepare outside, use in well-ventilated area, wear gloves
* AEs – acts as alpha-2-adrenoceptor agonist (like xylazine)
in mammals - sedation and bradycardia can be reversed
with alpha-2-adrenoreceptor antagonist, atipamezole

Question 22

What is the function of glucocorticoids?

Answer 22

Highly effective anti-inflammatory drugs, frequently used,
cheap
* prednisolone and dexamethasone most commonly used

Question 23

What is the function of ciclosprin?

Answer 23

Inhibits activation of T-lymphocytes on antigenic
stimulation by impairing the production of IL-2 and other Tcell derived cytokines.
– May take 2-4 weeks for improvement to occur
– AEs – transient vomiting & diarrhoea, gingival hyperplasia,
hirsutism, muscle weakness/cramps

Question 24

What is oclacinitib?

Answer 24

a Janus kinase (JAK) inhibitor - inhibits variety of
cytokines dependent on JAK enzyme activity – including
proinflammatory cytokines which have a role in allergic
responses/pruritis

Question 25

What is lokivetmab?

Answer 25

is a caninised monoclonal antibody for treatment
of atopic dermatitis in dogs
* Specifically targets the inflammatory cytokine canine
interleukin-31 (IL-31)