Anti-allergics

Question 1

what are 5 common treatments for allergies and atopy

Answer 1

glucocorticoids, antihistamines, oclacitinib, cyclosporine, lokivetmab

Question 2

explain basic pathogenesis of atopic dermatitis

Answer 2

environmental allergens trigger abnormal production of cytokines by T-helper cells in dogs with a genetic skin barrier defect. Th-2 cells secrete interleukins to trigger B cells to produce allergen-specific IgE, leading to mast cell activation, degranulation, and eosinophilic response. certain Th-2 cytokines cause pruritic and further skin damage by self-trauma. then, Th-1 cells secrete IFN-gamma and TNF-alpha and chronic inflammatory response occurs, predisposes to bacterial and yeast infections.

Question 3

what 2 things happen when sensitized mast cell (IgE bound to mast cell receptors) are bound by antigen

Answer 3

mast cell activation and degranulation

Question 4

what is a release of preformed mediators (histamine, proteases, and chemotactic substances) from sensitized mast cells

Answer 4

degranulation

Question 5

what is the synthesis of arachidonic acid from plasma membrane and production of prostaglandins and leukotrienes from sensitized mast cells

Answer 5

activation

Question 6

this class of anti-allergics are H1 antagonists. they are often used in treatment of canine atopic dermatitis in spite of little evidence of effectiveness, are usually given with corticosteroids initially, then are continued for long-term therapy

Answer 6

antihistamines

Question 7

name at least 2 adverse effects of antihistamines

Answer 7

CNS depression most common, GI effects, anticholinergic effects

Question 8

name at least 2 antihistamines used for treatment of allergies in small animals

Answer 8

diphenhydramine and hydroxyzine emphasized. also cetirizine, chlorpheniramine, trimeprazine, loratadine, mirtazapine, TCAs

Question 9

what 2 drugs should you not give with antihistamines

Answer 9

CNS depressants monoamine oxidase inhibitors (may also interact with ketoconazole and omega 3 and 6 products)

Question 10

this janus-kinase inhibitor anti-allergic drug is JAk-1 selective with some JAK-3 inhibition. it blocks the action of interleukins associated with B cell IgE production and action of IL-31 (associated with pruritis). good evidence for use with canine atopic dermatitis, but less evidence for use in cats. what is the drug?

Answer 10

oclacitinib

Question 11

what is the route of administration for oclacitinib? how often is it given?

Answer 11

orally. BID for 2 weeks then SID as maintenance

Question 12

why should you not give animals with active infections oclacitinib

Answer 12

immunomodulatory effects

Question 13

name 3 adverse effects of oclacitinib

Answer 13

mostly GI effects–diarrhea, vomiting, anorexia. immune suppression and infection. possible worsening of pre-existing tumours.

Question 14

what are the 2 oral formulations of cyclosporine? what is more predictably absorbable?

Answer 14

ultramicronized (Atopica brand) and vegetable oil based. ultramicronized (both formulations are absorbed in the small intestine; ultramicronized forms a microemulsion on contact with GI tract, while the vegetable oil product has varied bioavailability in dogs)

Question 15

what is cyclosporine labelled for treatment of in vet med? in which species?

Answer 15

atopic dermatitis in dogs (also used for other conditions). it is extra label in cats.

Question 16

what is the mechanism of action of cyclosporine

Answer 16

inhibits calcineurin within T lymphocytes, reducing transcription of cytokine-encoding genes, reducing cytokines. (so it is immunosuppressive, useful for atopic dermatitis)

Question 17

cyclosporine is expensive! what can you do to reduce the amount you need to use of it?

Answer 17

coadminister with ketoconazole (drug interaction will reduce amount of cyclosporine needed)

Question 18

you have started cyclosporine treatment on a patient and they get an upset tummy. what do you tell the client?

Answer 18

GI upset is common but usually decreases with time, and the medication rarely requires discontinuation

Question 19

this monoclonal antibody against IL-31 is given in dogs SQ every 4-8 weeks to reduce pruritis associated with atopic dermatitis. what is it

Answer 19

lokivetmab (Cytopoint brand)