Lecture 4: Drugs for the treatment of GI disorders-2

Question 1

What receptors are located in the vomiting center (medulla) that can be activated

Answer 1

Alpha1, 5-HT3, NK1, H1

Question 2

What receptors are in the vestibular nuclei that can induce vomiting

Answer 2

M1, M2, H1

Question 3

What receptors are in the periphery (GI and pharynx) that can induce vomiting

Answer 3

5-HT3, and NK1

Question 4

What receptors are in the chemoreceptor trigger zone that can induce vomiting

Answer 4

D2, 5-HT3, NK1

Question 5

When is the appropriate timeline to induce vomiting

Answer 5

Within 1hr of toxin ingestion

Question 6

When do you not want to induce vomiting

Answer 6

Ingested sharp objects, strong acids/bases or >1hr after ingestion

Question 7

When do you want to inhibit vomiting

Answer 7

Intractable, risk of aspiration, onset of acid-base disorders, onset of electrolyte disorders

Question 8

What are ondansetron HCl and dolasetron mesylate indicated for

Answer 8

Vomiting in cats and dogs

Question 9

What drugs tend to cause vomiting in dogs that can be reduced with ondansetron

Answer 9

Dexmedetomidine and buprenorphine

Question 10

What is the mechanism of action of ondansetron and dolasetron

Answer 10

5-HT3 receptor antagonists in the CRTZ, vomiting center, and periphery

Question 11

When is PO administration ineffective with ondansetron and dolasetron

Answer 11

Acute, intractable vomiting

Question 12

What route of administration of ondansetron and dolasetron have a greater absoprtion

Answer 12

SQ

Question 13

What are some adverse effects of dolasetron

Answer 13

Prolongs ECG intervals- caution with arrhythmias, electrolyte imbalances, chemotherapy tx

Question 14

What is an adverse effect/contraindication of ondansetron

Answer 14

Eliminated by P-glycoprotein so patients with MDR1 gene like collies should not be usd

Question 15

What is maropitant citrate indicated for

Answer 15

Acute vomiting in dogs and cats, motion sickness in dogs

Question 16

What is the mechanism of action of maropitant citrate

Answer 16

NK1 receptor antagonist in CRTZ, vomiting center and periphery

Question 17

What are some adverse effects of maropitant citrate

Answer 17

Prolongs QT interval- caution with arrrythmuas, hypersalivation

Question 18

What is apomorphine HCl indicated for

Answer 18

Enteric for dogs- primarily for ingested toxins

Question 19

What is the mechanism of action of apomorphine

Answer 19

D2 receptor agonist in CRTZ

Question 20

Since cats have fewer D2 receptors in CRTZ which drug should be used in place of apomorphine

Answer 20

Xylazine

Question 21

What are some adverse effects of apomorphine

Answer 21

Protracted vomiting, lethargy, hypersalivation

Question 22

If apomorphine induces protracted vomiting what can be done to treat it

Answer 22

Rinse conjunctiva

Question 23

What are some contraindications for apomorphine

Answer 23

Seizures, obtundation, comatose, abnormal gag reflex, rabbits

Question 24

What is chlorpromazine HCl indicated for

Answer 24

Antiemetic in dogs and cats, inhibits apomorphine induced dogs, motion sickness for cats

Question 25

What is the mechanism of action for chlorpromazine HCl

Answer 25

D2 receptor antagonist in the CRTZ Anti-histaminic, anti-cholinergic, anti-alpha adrenergic effects

Question 26

What are some adverse effects of chlorpromazine

Answer 26

Sedation, lethargy, tremors, ataxia, diarrhea, loss of anal sphincter tone, hypotension, excitation, bradycardia, lower seizure threshold

Question 27

What are some contraindications of chlorpromazine HCl

Answer 27

Horses, dog breeds with predisposition to MDR1 mutations

Question 28

What is metoclopramide HCl indicated for

Answer 28

General antiemetic for most purposes in dogs, gastric ulceration (promotility effects)

Question 29

What is the mechanism of action of metoclopramide

Answer 29

D2 receptor antagonism in CRTZ, some 5-HT3 antagonism in CRTZ, vomiting center and periphery, sensitizes GI smooth muscle to PNS stimulation

Question 30

What are some adverse effects of metoclopramide HCl

Answer 30

Aggressive behavior in horses, changes in mentation, constipation, increased detrusor muscle tone

Question 31

What are some signs of ulcers in small animals

Answer 31

Weight loss, anorexia, sporadic/chronic vomiting with blood, abdominal pain, anemia, Melena, secondary esophagitis

Question 32

What are some causes of ulcers in small animals

Answer 32

Drug induced from NSAIDS Helicobacter pylori

Question 33

What is equine squamous gastric ulcer syndrome associated with

Answer 33

Going off feed, because glandular stomach is constantly producing acid which is typically buffered by feed

Question 34

What is equine glandular gastric ulcer syndrome associated with

Answer 34

Breakdown in gastric mucus layer of the stomach

Question 35

What is the typical cause of equine glandular gastric ulcer syndrome resulting in breakdown of gastric mucus layer

Answer 35

NSAIDS

Question 36

What is omeprazole indicated for

Answer 36

FDA approved for gastric ulcer management in horses ELDU- gastric ulcers in small animals, esophagitis

Question 37

What is the mechanism of action for omeprazole and pantoprazole

Answer 37

Irreversible inhibition of H+/K+ ATPase at the secretory surface of parietal cells

Question 38

What type of gastric ulcer syndrome in horses is omeprazole better at treating

Answer 38

ESGUS

Question 39

T or F: crushing omeprazole tablets is the best way to administer them

Answer 39

False, the capsules contain coated granules that protect the drug in stomach, crushing them will reduce efficacy

Question 40

What are some H2 antagonists/proton pump inhibitors

Answer 40

1. Cimetidine 2. Famotidine 3. Nizatidine 4. Ranitidine

Question 41

What are H2 antagonists/proton pump inhibitors indicated for

Answer 41

Reducing gastric acid secretion in small animals

Question 42

Which H2 antagonist can treat ESGUS and is it not better than omeprazole

Answer 42

Ranitidine, less effective than omeprazole but cheaper

Question 43

What is the mechanism of action of H2 antagonists

Answer 43

Competitive antagonists of histamine secreted from ECL cells so blocks H+/K+ ATPase through inhibition of Gs and cAMP

Question 44

Which H2 antagonists have mild inhibition of AChE and therefore increase PNS tone (prokinetic)

Answer 44

Ranitidine and nizatidine

Question 45

What does it mean to be prokinectic

Answer 45

Increase gastric motility by mild inhibition of AChE in synaptic junctions—> increase PNS activity So ranitidine and nizatidine increase gastric motility and decrease gastric acid secretion

Question 46

What H2 antagonists inhibit P450 and what does that mean

Answer 46

Drugs: cimetidine>>ranitidine Increases time of circulation of drug/decrease metabolism. Also can affect metabolism of other drugs

Question 47

What is erythromycin indicated for

Answer 47

Primary gastroparesis, esophageal reflux, colonic motility disorders in cats and dogs

Question 48

What is the mechanism of action of erythromycin

Answer 48

Stimulates motilin receptors in cats, stimulates 5-HT3 receptors in dogs

Question 49

What are some adverse effects and contraindications for erythromycin

Answer 49

Stimulation of larger food particles into intestines causing intestinal distress Macrolide antibiotics may cause toxic entercolitis in pocket pets GI perforation, obstruction, hemorrhage

Question 50

What is cisapride indicated for

Answer 50

Primary gastroparesis, esophageal reflux, constipation and megacolon in cats

Question 51

What is the mechanism of action of cisapride

Answer 51

Modulates serotonin receptors Agonist of pre synaptic 5-HT4 receptors that increase release of ACh, stimulates gastric emptying and lower esophageal motility and sphincter pressure

Question 52

What are some adverse effects of cisapride

Answer 52

Vomiting, diarrhea, abdominal pain, increase Q-T intervals, GI perforation, obstruction, hemorrhage

Question 53

What is sucralfate indicated for

Answer 53

Ulcers in any GI location (oral to duodenum) except if caused by NSAIDS

Question 54

What is the mechanism of action of sucralfate

Answer 54

Binds protein exudates and basement membranes of cells in ulcer and coats ulcer protecting it from stomach acid allowing it to heal

Question 55

What are some adverse affects of sucralfate

Answer 55

Vomiting in cats, constipation

Question 56

What is misoprostol indicated for

Answer 56

NSAID induced gastric ulceration

Question 57

What is the mechanism of action of misoprostol

Answer 57

Synthetic prostaglandin E1 analogue inhibits H+/K+ ATPase by stimulating GI and inhibiting cAMP. Promotes bicarbonate and mucus production by gastric epithelial cells. Increases gastric blood supply and turnover of gastric epithelium

Question 58

What are some adverse effects of misoprostol

Answer 58

Diarrhea, vomiting, abdominal pain, abortion (increase uterine contraction, relax and thin cervix)