II - GI Large Animal Flashcards
What two drugs are used to treat esophageal obstruction in ruminants?
Acepromazine
Xylazine or detomidine
Name two ruminotorics
Mineral oil
Dicotyl sodium sulfosuccinate
Name two anti foaming agents.
Poloxalene
Polymerized methyl silicone
Neostigmine and bethanechol
N-butylscopolammonium bromide
Atropine
Xylazine
Metoclopramide
Erythromycin lactobionate
These are all:
Modulators of ruminoreticular motility
Species for which gastric ulceration tends to be more common
Horses, pigs, dogs, cats, zoo animals
NSAIDS, corticosteroids, stomach irritants, stress, disrupted mucosal blood supply, and inflammatory diseases are risk factors for ____.
Ulcers in veterinary patients
Gastric acid production is stimulated by these three things:
Histamine via H2 receptors
Vagal stimulation via ACh
Gastrin via CCK2 receptor
Mucosal protection is mediated primarily by ______ stimulation of:
Bicarbonate production
Mucus
Epithelial cell turnover and replacement
Adequate blood flow
PGE2
Drugs used for prevention and/or treatment of ulcers are divided into two categories:
Control _______
Promote ______
Gastric acidity
Mucosal protection
What do these kinds of drugs do?
Antacids
Anticholinergic agents
Antihistamines
Proton pump inhibitors
Control gastric acidity
Two common antihistamines (H2 receptor antagonists)
Ranitidine and Famotidine
Higher doses needed in horses because of limited oral absorption
H2 receptor antagonists block _________ stimulated by histamine as well as other stimuli of gastric acid secretion.
Gastric acid production
In horses, ______ are used to increase stomach pH and to improve or heal ulceration in foals or adult horses.
Antihistamines (H2 receptor agonists)
In calves, ______ is used to maintain the pH of the abomasum > 3.5.
Ranitidine (H2 receptor antagonist)
Drug interactions with antihistamines are due to ___.
Changes in pH
GastroGard and UlcerGard are FDA approved pastes for the treatment/prevention of ulcers in horses. These pastes are _______.
Proton pump inhibitors
- omeprazole
These drugs irreversibly bind to the H+,K+, ATPase proton pump, permanently inhibiting its action. The parietal cell must synthesize new enzyme in order to continue to secrete acid.
Proton pump inhibitors
___________ is superior to ____________ for healing ulcers.
omeprazole is superior to ranitidine for healing ulcers
_____ may occur when PPIs are discontinued.
Chronic administration can result in elevated levels of gastrin and ________.
Rebound hyperacidity
Bacterial overgrowth
PPIs are metabolized by _____
P450
Increment of pH can alter absorption of _____ and _____.
Antifungals and Mycophenolate
Three kinds of drugs that promote mucosal protection
Prostaglandin-analogues
Antacids (large volumes impractical in adult horses)
Sucralfate (no substantial efficacy in LA)
In horses, Misoprostol has been proposed for treatment of _______.
NSAID-associated right dorsal colitis
_____ is contraindicated in pregnant mares, because it can cause abortion. Pregnant women should handle it with extreme care.
Misoprostol (Cytotec)
Name a prostaglandin analog used in LA medicine.
Misoprostol
MOA: PGE series inhibit gastric acid secretion and promotes mucosal protection by enhanced bicarbonate secretion, enhanced mucus secretion, and enhanced mucosal blood flow
Misoprostol
This prostaglandin analogue does not cause rebound secretion of gastric acid, but it can cause intestinal hypersecretion and hyper motility resulting in nausea, diarrhea, and abdominal cramping (colic).
Misoprostol
______ is a neuropeptide that stimulates contraction of GI smooth muscle throughout most segments of the gut.
Motilin
The regulation of GI smooth muscle is complex, and involves these three influences:
Extrinsic influence - vagal and sympathetic nerves
Enteric nervous system
Receptors on smooth muscle cells
Name a condition in LA medicine that might require prokinetic drugs.
Post-operative ileus (POI)
Cholinergics, Metoclopramide, Erythromycin, and lidocaine are all ______.
Prokinetics - gastric motility modulators
_______ is the cholinergic agonist most used clinically for stimulating motility. It acts on the myenteric plexus and muscarinic receptor on smooth muscle cells.
Bethanechol
___________ is used primarily for treating delayed gastric emptying; also increases contraction of cecum and right ventral colon.
Bethanechol - cholinergic
This cholinergic is a cholinesterase inhibitor.
Neostigmine
Adverse effects of the cholinergic ______ include SLUD, bradycardia, colic (esp LA), and potential for increased gastric acid secretion.
Bethanechol
This drug is used to enhance cecal emptying in healthy ponies. It can also promote passage of gas in foals that have severe abdominal distention but no displacement or obstruction of colon.
Cholinergic
- Neostigmine
Horses usually get mild colic signs after administration of this drug.
Cholinergic
- Neostigmine
MOA: 5-HT4 agonist, 5HT3 antagonist, enhances ACh release
Prokinetic
- Metoclopramide
Metoclopramide’ s prokinetic effects are limited to the _____. It relaxes the ______ making it useful for promoting gastric emptying.
Proximal GI tract
Pyloric sphincter
_______ is contraindicated in patients with gastrointestinal obstruction or perforation.
It may cause CNS excitation, particularly in _____, or CNS depression.
Some sources list ____ as a contraindication as well.
Metoclopramide
Horses
Epilepsy
_____ promotes gastric and proximal intestinal motility. This has been attributed to stimulation of the motilin receptor.
Erythromycin
_______ is the second choice prokinetic after lidocaine used primarily for cecal impactions to improve gastric emptying.
Erythromycin
It has been suggested that _______ exerts its effects not by directly stimulating GI motility, but by preventing the inhibition of bowel motility.
Lidocaine
Potential adverse effects of ______ infusion include cardiac arrhythmias, muscle fasciculations, ataxia, and seizures.
Lidocaine
Prophylactic lidocaine treatment was associated with a significantly reduced incidence of ________ in horses undergoing small intestinal surgery for colic.
Post operative ileus
_________ is labeled for use in cases of equine colic and calf scours.
Anticholinergic
- hyoscine butylbromide (Buscopan)
Side effects of ________ include dry mouth, constipation, urinary retention, and tachycardia.
Anticholinergic
- hyoscine butylbromide (Buscopan)
Opioids used to treat diarrhea
Loperamide (Imodium - anecdotal use)
Butorphanol (used in combination with xylazine works even better)
Alpha 2 agonists used to treat diarrhea
Xylazine
Detomidine
______ was found to be effective in the treatment of severe non responsive diarrhea in adult horses.
Phenoxybenzamine
Magnesium sulfate, bismuth, and activated charcoal:
Either line the mucosal surface or absorb potential toxicants in the intestinal lumen.
This protectant/absorbent should be avoided in patients receiving glucocorticoids or NSAIDs.
Bismuth subsalicylate
Cathartics are agents that stimulate ____.
Defecation
