Autocoids & Anti-Histamines (final exam)

Question 1

Definition of autacoids

Answer 1

Chemical mediators that function in localized tissue and participate in physiological response to injury

Question 2

Examples of autacoids

Answer 2

Histamines
Serotonin (5-HT)
Prostaglandin
Peptides

Question 3

Where are histamines stored?

Answer 3

Throughout the body (lungs, skin, stomach), within mast cells

Question 4

Histamine release is triggered by:

Answer 4

Immune-induced (type 1 hypersensitivity)
Insect sting / envenomation
Drug-induced
Physical injury

Question 5

Antihistamines (H1 antagonists)

Answer 5

Diphenhydramine
Hydroxazine
Loratadine

Question 6

Janus kinase inhibitor

Answer 6

Oclacitinib

Question 7

Leukotriene inhibitor

Answer 7

Zafirlukast

Question 8

5-HT inhibitor

Answer 8

Trazadone

Question 9

Histamine receptors

Answer 9

Histamine-1 (H1)

Histamine-2 (H2)

Question 10

Effects of H1 agonism

Answer 10

Inflammation
Bronchoconstriction - smooth muscle contraction
Vasodilation - vascular smooth muscle relaxation
Mediate signs of urticarial and pruritis

Question 11

Effects of H2 agonism

Answer 11

Increased gastric HCl secretion

Vascular smooth muscle relaxation

Question 12

Anti-histamine drug targets

Answer 12

Mast cell stabilizers (glucocorticoids)
Physiologic histamine antagonists (catecholamines)
Therapeutic histamine antagonists (histamine receptors antagonists)

Question 13

Anti-histamine mechanism of action

Answer 13

Competitive H1 antagonism
Relaxation of bronchiolar smooth muscle
Inhibits vasodilation
Inhibits pruritis and itch stimulation

Question 14

Anti-histamine pharmacokinetics

Answer 14

High bioavailability

High Vd

Question 15

Adverse effects

Answer 15

Sedation is common (first gen more than second gen)
CNS depression
Antimuscarinic signs
Drug tolerance

Question 16

Drug of choice for allergic reactions

Answer 16

Diphenhydramine

Primarily used to treat type 1 hypersensitivity

Question 17

Hydroxyzine uses

Answer 17

Primarily used as adjunct in managing allergies
Most effective when administered prior to histamine signs
Poor efficacy for chronic allergic dermatopathies

Question 18

Loaradine uses

Answer 18

Non drowsy
Little documented animal efficacy
Some human versions contain xylitol

Question 19

Oclacitinib mechanism of action

Answer 19

Janus-Kinase inhibitor (JAK1 & JAK3)
Inhibits pro-inflammatory cytokines
Inhibits IL-31, sensation of itching
Directly targets pruritis

Question 20

Oclacitinib use

Answer 20

Treatment of allergic dermatopathy in dogs

Relief possible within 1 hour

Question 21

Oclacitinib adverse effects

Answer 21

GI signs
Polydipsia
Lethargy
Opportunistic infections possible

Question 22

Zafirlukast mechanism of action

Answer 22

Leukotriene receptor antagonist

Selective competitive antagonist for LTD4 and LTE4 receptors

Question 23

Zafirlukast uses

Answer 23

Adjunct treatment for feline asthma

Prevents bronchoconstriction in cats

Question 24

Trazadone mechanism of action

Answer 24

Serotonin antagonist reputable inhibitor (SARI)
5-HT2A and a1-adrenergic receptor antagonist
Increases serotonin levels in the brain

Question 25

Trazadone uses

Answer 25

Behavioral disorders
Post-surgical cage confinement
Separation anxiety

Question 26

Trazadone adverse effects

Answer 26

Caution in male breeding dogs, priapism
Seizures at large dose
Sedation
Shaking
GI upset