GI Flashcards
3 ulcer treatment goals
Reduce ulcerogenic factors
Enhance defensive factors
Eradicate any infectious cause
Pro-ulcerogenic
Acids (HCl, VFA’s, bile acids)
Pepsin
Infections
Anti-ulcerogenic
Mucosal cytoprotection
Epithelial renewal
External protection
3 ways to lower gastric acid secretion
H2-Histamine receptor antagonist (dec. cAMP) - Famotidine
Prostaglandin E receptor agonist (dec. cAMP) - Misoprostil
Proton Pump Inhibitors (inhibit H+/K+ ATPase) - Omeprazole “prazole”
List from most effective to least effective at reducing gastric HCl secretion
(H2-Histamine antagonist - Prostaglandin E agonist - Proton Pump Inhibitors)
(most) Proton Pump Inhibitors > H2-Histamine Antagonist > Prostaglandin E Agonist (least)
(most) Omeprazole > Famotidine > Misoprostol (least)
3 drugs that directly protect gastric mucosa
longer action/most effective > shorter action/least effective
Misoprostol > Sucralfate > Antacids
Sucralfate mechanism of action
Sucralfate
Decrease pepsin hydrolysis
Increase prostanoid formation
Increase epidermal growth factor
Increase gastric blood flow
Locally-acting Emetic Agents
Irritate GI mucosa
Warm Water
Sodium Chloride
3% Hydrogen Peroxide (cats can aspirate)
Emetine (alkaloid, 15-30 min to work, toxic in cats)
Centrally-acting emetic agents
Stimulate CNS vomiting centers
Apomorphine (D2-Dopamine receptor agonist)
for DOGS
Xylazine (Alpha2-adrenergic receptor)
for CATS
Conditions when you would decrease frequency of emesis
Motion sickness
Uremia, liver disease, endotoxemia
Cancer chemotherapy
Canine parvoviral gastroenteritis
Trauma
Peripherally-acting anti-emetic drugs
H2-Histamine Antagonists - Famotidine
(decrease acid output)
mAChR Antagonists - Isopropamide, glycopyrrolate
(decrease vagal afferent transmission to vomiting center, decrease GI muscle spasms, decrease GI secretions)
Coating agents - Kaolin-pectin, bismuth subsalicylate
Gastric Prokinetic drugs - Metoclopramide
(stimulate gastric motility and prevent relaxation of stomach and lower esophageal sphincter)
CNS-acting anti-emetic drugs
Dopamine antagonists - promazine, droperidol, metoclopramide
H1-Histamine Antagonists - diphenhydramine, meclizine
5HT-3 serotonin receptor blockers - ondansetron, dolasetron
Neurokinin 1 (substance P) blockers - maropitant (broad spectrum)
GI motility-enhancing drugs
Benzamides - Metoclopramide, Cisapride
Motilides - Erythromycin
Lidocaine
Metoclopramide (GI motility-enhancing)
Acts on upper GI tract - increases amplitude and frequency of smooth muscle contractions
Blocks D2-dopamine receptors
Agonist effects on 5-HT4-serotonin receptors
Cisapride (GI motility-enhancing)
Partial agonist at 5-HT4 receptors - increases ACh release
Inhibited by atropine
Stimulates motility throughout entire GI tract in cats and dogs
