Lecture 2: Respiratory Drugs and Treatments for Allergy

Question 1

What are some indications for antihistamines/H1 antagonists

Answer 1

Sedation, prophylaxis of atopic dermatitis, aseptic laminitis (cows), blood transfusions, tx MCT, motion sickness

Question 2

What are some first generation H1 antagonists

Answer 2

1. Diphehydramine HCl
2. Chloropheniramine maleate
3. Promethazine HCl
4. Trimeprazine tartrate
5. Hydroxyzine HCl

Question 3

What is the second generation H1 antagonist

Answer 3

Cetirizine

Question 4

How do H1 antagonist affect neurotransmission

Answer 4

Histamine is typically stimulatory so antagonist will block that excitatory effect- promotes sedation

Question 5

What are H1 antagonists role in anaphylaxis

Answer 5

Histamine typically causes vasodilation and reflex tachycardia in anaphylaxis, but H1 antagonist will block vasodilation so promote constriction and increase BP

Question 6

What is the mechanism in which histamine causes vasodilation

Answer 6

1. Histamine binds to H1 receptor
2. Activates NO synthase
3. NO acts on guanylyl Cyclase turning GTP to cGMP
4. Inhibits PLC
5. Promotes vascular smooth muscle relaxation

Question 7

Which has a lower VD- first or second generation h1 antagonists

Answer 7

2nd generation- cetirizine

Question 8

If you have a patient who needs to treat an allergy but doesn’t want to have sedative effect which drug should you put on and why

Answer 8

Ceterizine- second generation h1 antagonist that has lower VD- does not cross BBB so no sedative effect

Question 9

What are some adverse effects of h1 antagonists

Answer 9

Sedation, paradoxical excitation, anticholinergic effects, iatrogenic Cushing with temparil P

Question 10

Which h1 antagonist contains prednisolone

Answer 10

Temparil P

Question 11

Which generation of h1 antagonists cause anticholinergic effects

Answer 11

First generation

Question 12

What is oclacitinib labeled for

Answer 12

Treatment of pruritic atopic dermatitis

Question 13

What is the mechanism of action for oclacitinib

Answer 13

Competitive inhibitor of JAK1/JAK3–> inhibits signaling in target cells due to inflammatory cytokines

Question 15

What is the mechanism of action of lokivetmab

Answer 15

Caninized monoclonal antibody to IL-31, so can’t activate JAK1/2 pathways, reduces the perception of itch

Question 16

What are some adverse effects of lokivetmab

Answer 16

Erythema, anorexia

Question 17

What is cyclosporine A indicated for

Answer 17

Labeled: atopic dermatitis in dogs and cats
ELDU: keratoconjunctivitis sicca and autoimmune disorders

Question 18

What is the mechanism of action of cyclosporine A

Answer 18

Blocks calcineurin so can’t form NFAT which promotes production of IL-2

Question 19

What is tacrolimus indicated for

Answer 19

ELDU- atopic dermatitis and auto-immune dz

Question 20

What is the mechanism of action of tacrolimus

Answer 20

Blocks calcineurin so can’t form NFAT which promotes production of IL-2

Question 21

What are some adverse effects of calcineurin inhibitors

Answer 21

All species: vomiting, diarrhea, anorexia, hypersensitivity, gingival hyperplasia, hypertrichosis

Dogs: DM
Cats: hepatic lipodosis

Question 22

What are some contraindications of cyclosporine A

Answer 22

Hx of malignant neoplasia, use of live vaccines, FIV or FeLV positive, latent toxoplasma gondii

Question 23

What is dimethylsulfoxide indicated for

Answer 23

1. Labeled for reduction of inflammation secondary to trauma in dogs and horses
2. Commonly used as systemic anti-inflammatory in horses
3. Chronic endometritis in horses
4. Any inflammatory condition

Question 24

What is the mechanism of action of dimethylsulfoxide

Answer 24

Traps oxygen radicals and therefore reduces neutrophil and macrophage activity, inhibits prostaglandin synthesis

Question 25

What are some adverse effects of dimethylsulfoxide

Answer 25

IV: hemolysis, hemoglobinuria, diarrhea, muscle tremors, colic, odor Topical: burning sensation, erythema, vesisculation

Question 26

What is theophylline indicated for

Answer 26

ELDU: bronchoconstriction in dogs and cats, primarily used for coughs of unknown origin when all else fails

Question 27

What is the mechanism of action for theophylline

Answer 27

Inhibits smooth muscle contraction by inhibiting PDE IV, which increases cAMP. GS-linked adenosine receptors- increase cAMP

Question 28

What are some adverse effects of theophylline

Answer 28

CNS: nervousness, excitability, seizures Cardiac: tachycardia to arrhythmia Muscular: ataxia and tremors Urinary: PU/PD GI: nausea, vomiting, increased gastric pH

Question 29

What is ipratropium bromide indicated for

Answer 29

Bronchoconstriction in horses with RAO and small mammals- mostly feline asthma

Question 30

What is the mechanism of action of ipratropium bromide

Answer 30

Cholinergic antagonist- inhibits PNS tone, which increases normal SNS stimulation

Question 31

What are some side affects and contraindications for ipratropium bromide

Answer 31

Increased HR, decrease GI, urinary retention, increased IOP, hypertension, arrhythmias, colic, urinary obstruction CI: glaucoma, hepatic or renal insufficiency, atropine hypersensitivity

Question 32

What receptor does albuterol, clenbuterol, terbutaline target

Answer 32

B2-agonists

Question 33

What is albuterol indicated for

Answer 33

Treatment of bronchoconstriction in dogs, cats and horses

Question 34

What is the mechanism of action of albuterol

Answer 34

Directly stimulates relaxation of bronchial smooth muscles through B2 receptors

Question 35

What are some adverse effects of albuterol

Answer 35

Vasodilation, increased HR and contractility (B2 loses specificity at high dose and can target B1), decrease GI, increase insulin secretion, glycolysis, glycogenolysis, lipodosis, increase IOP

Question 36

What are some contraindications for albuterol

Answer 36

Cardiac dz including hypertension, hyperthyroidism, DM, low seizure threshold

Question 37

What is terbutaline indicated for

Answer 37

1. Acute bronchoconstriction in cats, birds, reptiles 2. Bradyarrythmias in dogs or cats 3. Premature labor-suppressed uterine contractions 4. Testing for anhidrosis in horses

Question 38

What is clenbuterol indicated for

Answer 38

Labeled for treatment of bronchoconstriction in horses/RAO

Question 39

What is the mechanism of action of clenbuterol

Answer 39

Activates B2 receptors on pulmonary macrophages which inhibits cytokine release- IL-1B and tNF-alpha

Question 40

What are some acute adverse effects of clenbuterol

Answer 40

Tachycardia, muscle tremors, increased serum creatinine kinase, sweating, restlessness, urticaria

Question 41

What are some chronic adverse effects of clenbuterol

Answer 41

Cardiac hypertrophy, suppression of cortisol response to exercise, altered immune function, reduced uterine tone and contractility, impaired reproductive function in males

Question 42

What are some contraindications for clenbuterol

Answer 42

Cardiac abnormalities, pregnancy

Question 43

What is fluticasone indicated for

Answer 43

Dogs-upper tracheobroncial disease Cats: asthma Horses: RAO but expensive

Question 44

What is the mechanism of action of fluticasone

Answer 44

Local pulmonary immunosuppression reducing inflammation and epithelial damage

Question 45

What are some adverse effects of fluticasone

Answer 45

Pharyngitis, upper respiratory infection, suppression of HPA, hypersensitivity, liver insufficiency