GI Drugs

Question 1

Which neurotransmitters inhibit appetite?

Answer 1

serotonin (5-HT2)

Question 2

Which neurotransmitters stimulate appetite?

Answer 2

• norepinephrine (a2)
• dopamine
• GABA (inhibits satiety center)
• ghrelin

Question 3

Benzodiazepines

• type of drug
• use
• formulations
• side effects/cautions

Answer 3

• GABA agonists
• stimulate GABA inhibits satiety center to increase appetite
• use short term only
• Diazepam IV, Midazolam IV or IM
• sedation, PO diazepam can cause hepatotoxicity in cats

Question 4

Propofol

• type of drug
• use
• caution

Answer 4

• GABA agonist
• very short term for appetite stimulant
• caution in cats: Heinz body anemia

Question 5

Capromorelin

• type of drug
• use

Answer 5

• Ghrelin receptor agonist

- Ghrelin stimulates hypothalamus to increase appetite

Question 6

Cyproheptadine

• type of drug
• use, what animal
• administration
• side effects

Answer 6

• serotonin antagonist
• inhibits satiety center, stimulating appetite
• effective in cats
• oral
• side effect is sedation

Question 7

Mirtazapine

• type of drug
• use, what animal

Answer 7

• serotonin antagonist
• blocks 5-HT receptors and increases NE, to stimulate appetite
• used in dogs more than cats

Question 8

Where is the emetic center located?

What does it contain?

Answer 8

• inside the BBB
• afferent nerves
• Neurokinin-1

Question 9

Where is the CRTZ?

What does it contain?

Answer 9

• outside the BBB

- serotonin, adrenergic, dopamine, metabolic

Question 10

How is the cat CRTZ different from the dog?

Answer 10

• cats have more alpha 2 and 5-HT, and fewer D2 and H1 (histamine)

Question 11

Hydrogen peroxide

• where and how does it act?
• use
• cautions

Answer 11

• peripherally acting emetic, direct irritation of oropharynx/GI lining
• used for immediate emesis if no other options
• don’t use in cats (hemorrhagic gastritis)
• don’t use other peripheral emetics

Question 12

Apomorphine

• type of drug
• how it acts
• which animal
• caution

Answer 12

• centrally acting emetic
• stimulates dopamine receptors (D2)
• more effective in dogs
• overdose can cause resp depression, reverse with naloxone

Question 13

Xylazine
Dexmedetomidine
- type of drug
- which animal

Answer 13

• centrally acting emetic
• alpha 2 agonists
• more effective in cats

Question 14

Maropitant citrate

• type of drug
• use
• caution

Answer 14

• neurokinin inhibitor
• prevention of motion sickness in dogs, and treatment of acute vomiting in dogs and cats
• injection stings

Question 15

Metoclopramide

• type of drug
• use
• administration

Answer 15

• dopamine antagonist (antiemetic)
• also blocks 5-HT3 receptors and is a prokinetic
• antagonizes apomorphine induced emesis
• oral or injectable

Question 16

Ondansetron

• type of drug
• use

Answer 16

• serotonin antagonist

- used for chemotherapy related nausea

Question 17

Cimetidine

• type of drug
• actions

Answer 17

• anti-ulcer medication
• anti-histamine (H2) blocker: competitive inhibtion
• inhibit gastric acid and pepsin secretion
• inhibitor of hepatic microsomal enzymes

Question 18

Famotidine

• type of drug
• compared to Cimetidine

Answer 18

• anti-ulcer

- more potent than Cimetidine, may last longer

Question 19

Ranitidine

• type of drug
• other effect

Answer 19

• anti-acid

- has some prokinetic activity

Question 20

What are the actions of Proton Pump Inhibitors?

Name a drug

Answer 20

• irreversibly inhibit H/K ATPase proton pump resulting in decreased hydrochloric acid production
• more potent than H2-blockers
• raises gastric pH
• Omeprazole for horses

Question 21

Misoprostol

• type of drug
• action
• use
• cautions

Answer 21

• anti-ulcer, prostaglandin E1 analog
• increases mucus and sodium bicarbonate secretion, stimulate epithelialization of mucosa and blood flow to heal ulcers
• used orally to treat NSAID-induced gastric ulcers
• cautions: abortifacient, can stimulate uterine contraction and cause diarrhea

Question 22

Sucralfate

• type of drug, formulation
• actions
• cautions

Answer 22

• anti-ulcer, sucrose-aluminum compound given orally
• binds to ulcer site and protects against acid, pepsin, and bile
• also stimulates protective PGs and antioxidants, and increases mucosal blood flow
• poorly absorbed, constipation, binds to other drugs

Question 23

Oral antacids

• name 3
• actions
• caution

Answer 23

• Aluminum, magnesium, and calcium salts
• chemically neutralize hydrochloric acid
• aluminum inactivates pepsin and binds to bile salts
• can cause constipation

Question 24

What substances increase GI activity?

What substances decrease GI activity?

Answer 24

• Increase: acetylcholine, serotonin, peptides

- Decrease: norepinephrine, dopamine, endorphins

Question 25

What are Emollient laxatives?

Answer 25

mechanical lubricants | - mineral oil, laxatone

Question 26

What are Simple Bulk laxatives?

Answer 26

absorb water from the lumen and swell up | - Psyllium

Question 27

What are Osmotic Cathartics?

Answer 27

osmotically draw fluid into the GI lumen | - Sugar alcohols, polyethylene glycol

Question 28

What are irritant cathartics?

Answer 28

irritate the GI mucosa to stimulate motility and secretions | - Bisacodyl

Question 29

What is Pancreatic enzyme replacement therapy? | - Which drugs are used?

Answer 29

- treatment for exocrine pancreatic insuficiency | - Viokase, Pancrezyme, Raw pancrease

Question 30

Lactulose - use - administration - action

Answer 30

- used in the management of hepatic encephalopathy - also a laxative - given orally, but can be given as retention enema - ion trap ammonia in the colonic lumen to enhance removal from body

Question 31

Ursodiol - made from what - use - actions - cautions

Answer 31

- bile acid salt obtained from bears, now synthesized - used in chronic inflammatory liver disease in small animals - increases bile flow - contraindicated if biliary obstruction - can interfere with bile acid tests