Antihistamines

Question 1

What functions are H1 thought to control?

Answer 1

Affects vascular smooth muscle, endothelium, airways, and peripheral nerves (itch sensation)

Question 2

What functions are H2 thought to control?

Answer 2

Heart rate, contractility, and stomach acid secretion

Question 3

What functions are H3 thought to control?

Answer 3

Wakefulness in the CNS

Question 4

Diphenhydramine mechanism and use?

Answer 4

(Benedryl) H1 inhibition. Crosses the BBB; broad range of use - prevent anaphlaxis, atopy, sedation, anti-emetic

Question 5

Cyproheptadine mechanism and use?

Answer 5

H1 Inhibition. + anticholinergic + serotonin antagonist //

Appetite stim in cats, and Tx for serotonin sickness in dogs // Little histamine activity

Question 6

Meclizine

Answer 6

H1 antiemetic + Tx of vestibular DZ in dogs

Question 7

Famotidine

Answer 7

H2 antacid w/ high potency and long duration of action

Question 8

Selegiline

Answer 8

MAO serotonin degradation inhibition - MAO-A at high doses, MAO-B at low doses // Tx of K9 cognitive dysfunction

Question 9

Clomipramine

Answer 9

TCA approved in dogs with separation anxiety and dominance aggression // Off label in cat stress urination

Question 10

Fluoxitine

Answer 10

SSRI - approved in dogs w/ separation anxiety // Side effect = appetite reduction

Question 11

Mirtazapine

Answer 11

Block of 5-HT and A2 neurotransmitter + increases NE neurotransmission // Apetite stimulant and antiemetic

Question 12

Trazodone

Answer 12

Serotonin 5-HT antagonist + weak SSRI // confinement anxiety + sleep facilitator

Question 13

Cisapride

Answer 13

Seritonin 5-HT antagonist + increased acetylcholine release // Increase GI motility to Tx Gastric stasis, gastric reflux, and megacolon (cats)

Question 14

Ondasetron

Answer 14

Seritonin 5-HT antagonist // potent anti emetic (used with chemotherapy)