22 – GI Miscellaneous

Question 1

Exocrine pancreatic insufficiency

Answer 1

• Failure of exocrine pancreas to produce Lipase Amylase and Tripsin for DIGESTION of normal diet
• Mainly in dogs

Question 2

What can be used to treat exocrine pancreatic insufficiency?

Answer 2

• *Pancrelipase (Pank-Aid)
• (Octreotide (Sandostatin))
• (Fuzapladib (Panoquell-CA1))

Question 3

Pancrelipase (Pank-Aid) (‘ground pancreas’)

Answer 3

• Supplement of exocrine pancreas enzymes (lipases, amylase and proteases)
• Mix it with the food, let it sit so it can start to ‘digest’ the food before feeding it to the dog
• increased gastric pH may increase the amount of active enzyme reaching duodenum
• should wipe mouth after eating as it will ‘break down’ the nose structure

Question 4

What might be used to treat constipation?

Answer 4

• Lubricants
• (stimulant laxatives)
• Hyperosmotic laxatives
• Bulk laxatives
• Stool softeners

Question 5

Lubricants to treat constipation

Answer 5

• Mineral oil: cattle, horses
• Mineral oil + white petroleum: cats=hairball remedy
• *if get into lungs=bad pneumonia that will kill them!
  o NEEDS to go into the stomach

Question 6

Stimulant laxatives

Answer 6

• Irritate the mucosa or intrinsic nerves (ENS) causing motility

Question 7

Hyperosmotic laxatives

Answer 7

• Draw fluid into GI lumen to stimulate motility

Question 8

What are some examples of hyperosmotic laxatives?

Answer 8

• *Polyethylene glycol (PEG) powder
  o ¼ tsp: Mix in food for cats
• Sodium phosphate enemas: do NOT use in cats
  o Can cause hyperphosphatemia (absorb P=toxic)
• Lactulose
  o Non-digestible sugar

Question 9

Bulk laxatives

Answer 9

• Non-absorbed cellulose material with INCREASE the bulk of fecal material
  o Hydrophilic colloids: Metamucil (Drink right away, otherwise it will turn into gel)
  o Fiber: prunes, pumpkin

Question 10

Stool softeners (not really used)

Answer 10

• Increase water accumulation in feces
• Docusates
  o (Dioctyl sodium sulfosuccinate)
  o (Dioctyl calcium sulfosuccinate)

Question 11

Probiotics for diarrhea/constipation (theory)

Answer 11

• Bacteria or yeast added to food with purpose of relating intestinal flora
• Mechanism of action: unknown
• No reports of adverse effects
  o Downsides might be lack of efficacy and expense

Question 12

Trying to fix motility drugs

Answer 12

• Really DOESN’T work

Question 13

Motility-modifying drugs

Answer 13

• Metoclopramide: upper GI
• Cisapride: lower and upper GI
  *used as a prokinetic

Question 14

Motility-modifying drugs that have prokinetic effect as a side effect

Answer 14

• Erythromycin, azithromycin
• Cimetidine, ranitidine
• Lidocaine

Question 15

Metoclopramide (injectable solution)

Answer 15

• Inhibits dopamine receptors
• Inhibits serotonin receptors (5HT3)
• *stimulates serotonin receptor (5HT4)
  o Accounts for prokinetic effect
• *UPPER GI (stomach)

Question 16

Metoclopramide in upper GI

Answer 16

• Prokinetic effect: increase gastric and upper duodenal emptying
• Increase gastroesophageal sphincter tone

Question 17

Metoclopramide adverse effects

Answer 17

• Make sure there is NO GI obstruction
• Watch for extrapyramidal effects
• Can increase prolactin secretion

Question 18

Metoclopramide in horses

Answer 18

• AVOID

Question 19

Cisapride

Answer 19

• No approved vet or human formulation
  o Formerly Prepulsid (human tablets)
  o Now compounded products only

Question 20

What is Cisapride mechanism of action

Answer 20

• 5-HT4 agonist
• 5-HT3 antagonist
• Likely more effective prokinetic

Question 21

Cisapride vet uses in cats

Answer 21

• Increase smooth muscle motility
  o Used for MEGACOLON

Question 22

Cisapride vet uses in dogs

Answer 22

• Increase smooth muscle motility throughout GIT
  o Increase gastroesophageal sphincter one
  o Delayed emptying, small bowel motility disorders
  o Not effective for megaesophagus in dogs (little smooth muscle present)

Question 23

Cisapride vet uses in horses

Answer 23

• Treatment of ileus after abdominal surgery (IV use)
  o Co-ordinated motility in ileum/cecum/colon

Question 24

PK of Cisapride

Answer 24

• 30-60% oral bioavailability
• Longer half life in dogs and cats than horses and ruminants

Question 25

Adverse effects of Cisapride

Answer 25

- Cardiac arrythmias and drug interactions - Not reported in dogs and cats: but can happen

Question 26

Erythromycin, Azithromycin

Answer 26

- Though to activate motilin receptors in stomach and SI - LITTLE effect - Not available - Can cause vomiting and irritation?

Question 27

Lidocaine

Answer 27

- Horses to reduce post-op ileus (IV infusion) o VERY EXPENSIVE - Adverse effects: muscle fasciculations, ataxia, seizure