1AB Small Animal Gastrointestinal Pharmacology Overview

Solitary tract nucleus, Periphery, and Chemoreceptor trigger zone

note: same as Metoclopramide

Name the locations that the antiemetic drug Odansetron acts on in cats:

Solitary tract nucleus, Vomiting center in the medulla, Vestibular apparatus

Name the locations that the antiemetic drug Maropitant acts on in cats:

Solitary tract nucleus, Periphery, Chemoreceptor trigger zone

note: same as Ondansetron

Name the locations that the antiemetic drug Metoclopramide acts on in cats:

To remove the toxicant from the upper GIT within 4-6 hours of ingestion in patients (ex. grapes, chocolate, xylitol)

EXCEPTION: Do NOT do this for corrosive (battery acid) or sharp objects or petroleum distillates. Do NOT do in animals showing clinical signs

Why would we want to induce emesis in small animal patients? What is the EXCEPTION to this?

DOGS have MORE than cats

Which animal has MORE dopamine agonist receptors that stimulate CTZ for emesis, cats or dogs?

a. Ropinirole (clevor)

What is the FDA approved selective dopamine-2 receptor agonist that stimulates CTZ to induce emesis in dogs which has tachycardia as a side effect:

a. Ropinirole (clevor)

b. Apomorphine

c. 3% Hydrogen Peroxide

d. Xylazine

e. Dexmedetomidine

b. Apomorphine

What is the opioid derivative and nonselective dopamine receptor agonist that stimulates CTZ to induce emesis in dogs:

a. Ropinirole (clevor)

b. Apomorphine

c. 3% Hydrogen Peroxide

d. Xylazine

e. Dexmedetomidine

Naloxone

Apomorphine is an opioid derivative and nonselective dopamine receptor agonist that stimulates CTZ to induce emesis in dogs. This means you can use WHAT to reverse it?

DO NOT GIVE ORALLY

Which way can you NOT administer Apomorphine, an emetic in dogs?

a. Ropinirole (clevor)

c. 3% Hydrogen Peroxide

d. Apomorphine

Select the following emetics which can be used in DOGS only:

a. Ropinirole (clevor)

b. Xylazine

c. 3% Hydrogen Peroxide

d. Apomorphine

e. Dexmedetomidine

b. Xylazine

e. Dexmedetomidine

Select the following emetics which can be used in CATS only:

a. Ropinirole (clevor)

b. Xylazine

c. 3% Hydrogen Peroxide

d. Apomorphine

e. Dexmedetomidine

PERIPHERAL: 3% hydrogen peroxide

There are 3 emetics in dogs. Which one of them acts peripherally, where the other two act centrally?

Cats

Which animal can 3% hydrogen peroxide NOT be used in to induce emesis because it causes fatal respiratory issues?

c. 3% Hydrogen Peroxide

Select the peripheral emetic which causes local irritation to the stomach in dogs to induce vomiting:

a. Ropinirole (clevor)

b. Xylazine

c. 3% Hydrogen Peroxide

d. Apomorphine

e. Dexmedetomidine

CATS

Which animal's induced vomiting is mediated by alpha-2 receptors in the CTZ, cats or dogs?

Xylazine and Dexmedetomidine

DEXMEDETOMIDINE IS BEST

Name the two emetics which can ONLY be used in cats, as they are alpha-2 receptor agonists? Which is best?

XYLAZINE: yohimbine

DEXMEDETOMIDINE: atipamezole

Xylazine and Dexmedetomidine are alpha 2 agonists which can be used in cats to induce emesis. However, their side effects include CNS depression. What can you use to reverse the effects of each of these drugs?

a. Capromorelin (entyce)

Which appetite stimulant in dogs mimics endogenous ghrelin hormone that triggers the release of growth hormone and insulin like growth factor 1?

a. Capromorelin (entyce)

b. Mirtazapine (mirtaz)

c. Capromorelin (elura)

d. Cyproheptadine

b. Mirtazapine (mirtaz)

Which appetite stimulant in cats AND dogs is an anti-depressant with antagonism of serotonin receptors which result in appetite stimulation and have antiemetic effects + it antagonizes H1 histamine and presynaptic alpha 2 receptors?

a. Capromorelin (entyce)

b. Mirtazapine (mirtaz)

c. Capromorelin (elura)

d. Cyproheptadine

DOGS: Entyce

CATS: Elura

What is the difference between the CAT and DOG Capromorelin names?

WIDE

note: discontinue this med if no response in 5 days

What is the margin of safety like on Capromorelin (Entyce)?

Do not use with other selective serotonin reuptake inhibitors (fluoxetine, metoclopramide, erythromycin, cimetidine) = will cause serotonin reuptake syndrome

What do you have to avoid using Mirtazapine (an appetite stimulant for cats and dogs) with?

Liver and renal disease

Mirtazapine (an appetite stimulant) will have decreased clearance with WHAT DISORDERS, so you have to lower the dose in cats?

c. Capromorelin (elura)

Which appetite stimulant in cats is a ghrelin receptor agonist but may cause hypersalivation, GI upset, and behavior changes?

a. Capromorelin (entyce)

b. Mirtazapine (mirtaz)

c. Capromorelin (elura)

d. Cyproheptadine

d. Cyproheptadine

Which appetite stimulant in cats is an antihistamine that blocks H1 histamin receptors and inhibits serotonergic receptors which control appetite?

a. Capromorelin (entyce)

b. Mirtazapine (mirtaz)

c. Capromorelin (elura)

d. Cyproheptadine

Acromegaly and diabetes mellitus

It is contraindicated to use Capromorelin Elura (an appetite stimulant for cats) in animals with WHAT conditions?

b. Mirtazapine (mirtaz)

c. Capromorelin (elura)

d. Cyproheptadine

All of the following are appetite stimulants. Select which of the following can be used in cats:

a. Capromorelin (entyce)

b. Mirtazapine (mirtaz)

c. Capromorelin (elura)

d. Cyproheptadine

a. Capromorelin (entyce)

b. Mirtazapine (mirtaz)

All of the following are appetite stimulants. Select which of the following can be used in dogs:

a. Capromorelin (entyce)

b. Mirtazapine (mirtaz)

c. Capromorelin (elura)

d. Cyproheptadine

Phenothiazines, Dopamine antagonists, Serotonin (5-HT) antagonists, Neurokinin-1 receptor antagonists

What are the 4 main categories of antiemetics which can be used in animals?

Phenothiazine

Chlorpromazine, mepazine, and prochlorpromazine are all examples of WHAT category of antiemetic?

Phenothiazines

Which category of antiemetic should not be used in epileptic dogs because it can lower the seizure threshold?

Dopamine receptor antagonist

Metoclopramide is WHAT category of antiemetic?

b. metoclopramide

Which antiemetic drug is a dopamine receptor antagonist in the CTZ, meaning it is more effective in dogs than cats, increasing esophageal sphincter tone, duodenal pyloric relaxation, and antegrade contraction of the gastric antrum?

a. chlorpromazine

b. metoclopramide

c. ondansetron

d. maropitant

a. CTZ dopamine receptor antagonist

b. increased esophageal sphincter tone

e. increases antegrade contraction of gastric antrum

Select which of the following are true for the METACLOPRAMIDE antiemetic:

a. CTZ dopamine receptor antagonist

b. increased esophageal sphincter tone

c. helps fight chemotherapeutic emesis

d. helps fight pre-surgical emesis

e. increases antegrade contraction of gastric antrum

f. serotonin receptor antagonist

c. helps fight chemotherapeutic emesis

d. helps fight pre-surgical emesis

f. serotonin receptor antagonist

elect which of the following are true for the ONDANSETRON antiemetic:

a. CTZ dopamine receptor antagonist

b. increased esophageal sphincter tone

c. helps fight chemotherapeutic emesis

d. helps fight pre-surgical emesis

e. increases antegrade contraction of gastric antrum

f. serotonin receptor antagonist

c. ondansetron

Which drug is a serotonin receptor antagonist at 5HT3, best as an antiemetic against chemotherapeutic induced emesis, presurgical emesis, and parvovirus emesis?

a. chlorpromazine

b. metoclopramide

c. ondansetron

d. maropitant

Neurokinin-1 receptor antagonist blocking substance P

What is the MOA of maropitant (cerenia), an antiemetic?

d. maropitant

Which centrally acting antiemetic blocks impulses at the emetic center, but has pain on injection (which is why you keep it cold) and may cause bone marrow suppression in puppies under 8 weeks old (ex. parvo patients)?

a. chlorpromazine

b. metoclopramide

c. ondansetron

d. maropitant

Maropitant (cerenia)

Which antiemetic best works for motion sickness?

Acid-titrating drugs

These antacids include aluminum hydroxide, magnesium hydroxide, and calcium carbonate, overall weak and not a primary treatment

a. acid titrating drugs

These antacids are used in gastritis, ulcers, and esophageal reflux treatment, though they lack systemic effects, only locally decreasing pepsin activity and binding to bile acids

a. acid titrating drugs

b. H2 receptor antagonists

c. proton pump inhibitors

1. BEST: proton pump inhibitors

2. H2 receptor antagnoists

3. WORST: acid-titrating drugs

Put the following treatments in order from BEST to WORST:

1. H2 receptor antagonists

2. Acid-titrating drugs

3. proton pump inhibitors

c. aluminum hydroxide

d. calcium carbonate

Select which of the following are ACID TITRATING drugs:

a. famotidine

b. omeprazole (prilosec)

c. aluminum hydroxide

d. calcium carbonate

e. ranitidine

f. esomeprazole (nexium)

a. famotidine

e. ranitidine

Select which of the following are H2 receptor antagonist drugs:

a. famotidine

b. omeprazole (prilosec)

c. aluminum hydroxide

d. calcium carbonate

e. ranitidine

f. esomeprazole (nexium)

b. omeprazole (prilosec)

f. esomeprazole (nexium)

Select which of the following are proton pump inhibitor drugs:

a. famotidine

b. omeprazole (prilosec)

c. aluminum hydroxide

d. calcium carbonate

e. ranitidine

f. esomeprazole (nexium)

a. acid titrating drugs

Which drug binds to other oral drugs like tetracyclines, fluoroquinolones, and digoxin, so these must be administered first, then the following selected drug 2 hours later:

a. acid titrating drugs

b. H2 receptor antagonists

c. proton pump inhibitors

Famotidine

Which is the most COMMONLY used H2 receptor antagonist gastric acid secretion inhibitor?

b. H2 receptor antagonists

Which category of drug decreases acid secretion induced by feeding, increases intraluminal bicarbonate and mucous secretion?

a. acid titrating drugs

b. H2 receptor antagonists

c. proton pump inhibitors

Ranitidine

Which H2 receptor antagonist gastric acid secretion inhibitor ALSO has prokinetic effects on the stomach?

Cimetidine

Which H2 receptor antagonist gastric acid secretion inhibitor decreases drug metabolism due to inhibition of P450 enzymes?

c. proton pump inhibitors

Which category of drug blocks the H/K ATPase enzyme on the gastric luminal side:

a. acid titrating drugs

b. H2 receptor antagonists

c. proton pump inhibitors

Proton pump inhibitor

What is the MOST POTENT gastric acid inhibitor causing long lasting and pronounced decrease in acid secretion, which overall should be tapered to avoid rebound hypersecretion of gastric acid?

Misoprostol (Cytotec)

This drug is a synthetic prostaglandin E2 analog with specific activity for parietal cell receptors and decreases histamine, pentagastrin, and meal-stimulated gastric acid secretion

b. Misoprostol

The problem with this drug is that it stimulates intestinal motility and secretion, resulting in diarrhea and uterine contractions, making it CONTRAINDICATED in pregnancy:

a. Iansoprazole

b. Misoprostol

c. Sucralfate

d. Metronidazole

b. Misoprostol

Which drug is often used for prevention and treatment of NSAID induced ulceration, increasing gastric mucous and bicarbonate production:

a. Iansoprazole

b. Misoprostol

c. Sucralfate

d. Metronidazole

c. Sucralfate

This drug forms stable complexes with proteins from damaged mucosa to act as a diffusion barrier and absorb bile salts, overall used to treat esophagitis and gastroduodenal ulceration and erosion:

a. Iansoprazole

b. Misoprostol

c. Sucralfate

d. Metronidazole

Mucosal protectant

Overall, what two words would you use to describe sucralfate?

c. Sucralfate

Which drug, when coadministered with doxycycline, ciprofloxacin, or theophylline, SIGNIFICANTLY decreases bioavailability, so the following selected drug must be given 2 hours AFTER the aforementioned drugs:

a. Iansoprazole

b. Misoprostol

c. Sucralfate

d. Metronidazole

Liquid suspension

Sucralfate must be administered as a liquid suspension or tablet

PPIs

Which is superior for management of gastroduodenal ulceration and erosion: sucralfate or PPIs

2x daily

PPIs administered HOW OFTEN is considered the standard of care for cats and dogs fighting gastroduodenal ulceration and erosion?

Stress related mucosal damage, often occurring in high performance dogs (sled dogs, greyhounds), can be combated with prophylactic administration of PPIs which will increase performance

How are PPIs related to stress related mucosal damage?

TRUE

TRUE OR FALSE: PPIs are not indicated as part of triple treatment of helicobacter

They prevent injury by increasing pH of reflux (making it more alkaline)

PPIs do not decrease amount of gastric reflux. So what are they good for?

Giardia, Helicobacter, Clostridium

What infections is the antibiotic metronidazole good against?

Neurotoxicity

What is the MAIN side effect of metronidazole?

Tylosin (Tylan)

Which antibacterial is best to treat antibiotic responsive enteritis and inflammatory bowel disease?

Macrolide = binds 50S ribosome, inhibits protein synthesis

What is the MOA of Tylosin (Tylan), an antibacterial?

Inhibit DNA gyrase = prevent DNA synthesis

What is the MOA of Enrofloxacin, an antibacterial?

Histiocytic ulcerative colitis in boxers

note: be careful using this in boxers and frenchies, they have a tendency to develop resistance

What does enrofloxacin best treat in small animals?

b. enrofloxacin

Which antibacterial has adverse effects which include cartilage damage in puppies under 28 weeks old, retinotoxicity (blindness) in cats, and vomiting/diarrhea:

a. metronidazole

b. enrofloxacin

c. tylosin (tylan)

d. Sulfasalazine

d. Sulfasalazine

This antibiotic has an antiinflammatory component, used to treat inflammation of the large bowel in dogs:

a. metronidazole

b. enrofloxacin

c. tylosin (tylan)

d. Sulfasalazine

d. Sulfasalazine

This antibiotic has a sulfapyridine-5-aminosalacylic acid compound that's broken down in the colon, killing bacteria by acting as a competitive antagonist for aminobenzoic acid and 5-aminosalicylic acid being antiinflammatory:

a. metronidazole

b. enrofloxacin

c. tylosin (tylan)

d. Sulfasalazine

Because of the salicylic acid component

Why do you need to be careful using antibiotic sulfasalazine in cats?

Limited to upper intestinal tract

Metoclopramide is a prokinetic, but it is limited to WHERE?

b. cisapride

note: this is not metaclopramide because that drug is limited to the UPPER GI

Which prokinetic has dose dependent increased activity at all GI sites from the esophagus to the colon, used to manage chronic constipation and megacolon in cats:

a. metaclopramide

b. cisapride

c. misoprostol

d. erythromycin

e. ranitidine

f. nizatidine

b. cisapride

Which drug should NOT be combined with drugs that inhibit cytochrome P450 enzymes like itraconazole and ketoconazole, or it will cause FATAL ARRHYTHMIA:

a. metaclopramide

b. cisapride

c. misoprostol

d. erythromycin

e. ranitidine

f. nizatidine

a. manage chronic constipation

d. manage megacolon in cats

Select the indications for using cisapride, a prokinetic:

a. manage chronic constipation

b. manage parvoviral diarrhea

c. manage hepatotoxicity

d. manage megacolon in cats

e. manage GDV in german shepherds

f. manage gastroduodenal ulceration and erosion in high sport animals

They are prokinetics

What do metoclopramide, cisapride, erythromycin, ranitidine, nizatidine, and misoprostol all have in common?

a. bismuth subsalicylate

This GI protectant and absorbant has antisecretory and antimicrobial effects but you MUST BE CAUTIOUS OF USING IT IN CATS:

a. bismuth subsalicylate

b. activated charcoal

c. kaolin-pectin

c. kaolin-pectin

This GI protectant and absorbent binds and removes bacteria and their metabolic toxins, which can improve stool consistency:

a. bismuth subsalicylate

b. activated charcoal

c. kaolin-pectin

Cats

Azithoprine is an antiinflammatory drug for inflammatory bowel disease. It should NOT BE USED IN WHICH ANIMAL?

Laxatives

DSS and Psyllium are examples of laxatives or cathartics.

note: Laxatives and cathartics both treat constipation by promoting bowel movements, but differ in intensity and mechanism. Laxatives are generally milder, softening stool and easing evacuation. Cathartics (or purgatives) are stronger, inducing a rapid, often watery, evacuation of the entire colon

Cathartic

Osmotic lactulose is an example of a laxative or cathartic.

a. don't use with other SSRIs to prevent serotonin syndrome (dogs and cats) + decreased clearance with renal and liver disease (cats)

Which contraindication goes with Mirtazapine:

a. don't use with other SSRIs to prevent serotonin syndrome (dogs and cats) + decreased clearance with renal and liver disease (cats)

b. don't use with acromegaly or diabetes mellitus patients

c. can lower seizure threshold

d. pain on injection, bone marrow hypoplasia in puppies under 8 weeks old

e. decreased drug metabolism due to inhibition of P450 enzymes

f. stimulates intestinal motility and secretion - contraindicated in pregnancy

b. don't use with acromegaly or diabetes mellitus patients

Which contraindication goes with Capromorelin (cats):

a. don't use with other SSRIs to prevent serotonin syndrome (dogs and cats) + decreased clearance with renal and liver disease (cats)

b. don't use with acromegaly or diabetes mellitus patients

c. can lower seizure threshold

d. pain on injection, bone marrow hypoplasia in puppies under 8 weeks old

e. decreased drug metabolism due to inhibition of P450 enzymes

f. stimulates intestinal motility and secretion - contraindicated in pregnancy

c. can lower seizure threshold

Which contraindication goes with phenothiazines:

a. don't use with other SSRIs to prevent serotonin syndrome (dogs and cats) + decreased clearance with renal and liver disease (cats)

b. don't use with acromegaly or diabetes mellitus patients

c. can lower seizure threshold

d. pain on injection, bone marrow hypoplasia in puppies under 8 weeks old

e. decreased drug metabolism due to inhibition of P450 enzymes

f. stimulates intestinal motility and secretion - contraindicated in pregnancy

d. pain on injection, bone marrow hypoplasia in puppies under 8 weeks old

Which contraindication goes with maropitant:

a. don't use with other SSRIs to prevent serotonin syndrome (dogs and cats) + decreased clearance with renal and liver disease (cats)

b. don't use with acromegaly or diabetes mellitus patients

c. can lower seizure threshold

d. pain on injection, bone marrow hypoplasia in puppies under 8 weeks old

e. decreased drug metabolism due to inhibition of P450 enzymes

f. stimulates intestinal motility and secretion - contraindicated in pregnancy

e. decreased drug metabolism due to inhibition of P450 enzymes

Which contraindication goes with cimetidine:

a. don't use with other SSRIs to prevent serotonin syndrome (dogs and cats) + decreased clearance with renal and liver disease (cats)

b. don't use with acromegaly or diabetes mellitus patients

c. can lower seizure threshold

d. pain on injection, bone marrow hypoplasia in puppies under 8 weeks old

e. decreased drug metabolism due to inhibition of P450 enzymes

f. stimulates intestinal motility and secretion - contraindicated in pregnancy

f. stimulates intestinal motility and secretion - contraindicated in pregnancy

Which contraindication goes with misoprostol:

a. don't use with other SSRIs to prevent serotonin syndrome (dogs and cats) + decreased clearance with renal and liver disease (cats)

b. don't use with acromegaly or diabetes mellitus patients

c. can lower seizure threshold

d. pain on injection, bone marrow hypoplasia in puppies under 8 weeks old

e. decreased drug metabolism due to inhibition of P450 enzymes

f. stimulates intestinal motility and secretion - contraindicated in pregnancy

e. coadministration with doxycycline, ciprofloxacin, theophylline decreases bioavailability

Which contraindication goes with sucralfate:

a. don't use with other SSRIs to prevent serotonin syndrome (dogs and cats) + decreased clearance with renal and liver disease (cats)

b. don't use with acromegaly or diabetes mellitus patients

c. can lower seizure threshold

d. pain on injection, bone marrow hypoplasia in puppies under 8 weeks old

e. coadministration with doxycycline, ciprofloxacin, theophylline decreases bioavailability

f. stimulates intestinal motility and secretion - contraindicated in pregnancy