Unit 3- GI Flashcards
Reflex Emetics
Distension can induce emesis, water can dilute poison, salt in pharynx or solution, hydrogen peroxide
Prokinetic Drugs
Increase GI motility
Metoclopramide
Central and peripheral emetic, dopaminergic, serotonin antagonist and agonist, increases Ach release in GI
Metoclopramide Effects
Increase gastric emptying, increase esophageal sphincter tone, stimulates duodenum motility, increase prolactin and aldosterone
Metoclopramide Small Animal Use
Stimulate motility after surgery, volvulus, postop ileus, gastric ulceration, gastroparesis, not for obstruction or perforation
Metoclopramide Horse Use
Reduce postop ileus, stimulates small intestine, causes behavior changes and abdominal pain
Metoclopramide Ruminant Use
May increase rumen motility, treat pyloric stenosis
Cisapride
Enhance Ach release at myenteric plexus, increased GI activity at all sites
Cisapride Use
Reflux, delayed emptying, small bowel motility disorders, increases lower esophageal sphincter tone, chronic constipation in cat
Domperidone
Dopamine antagonist, does not cross BBB, accelerate small intestine transit
Domperidone Use
Fescue toxicity in horses, increase laminal blood flow to treat vasculitis
Erythromycin
Stimulates GI motility at lower doses than antibacterial, activates motilin receptors in stomach and proximal intestine
Lidocaine
IV in horses improves intestinal motility, may prevent inflammation
Peripheral Opiate Antagonists
Promotes motility and treats opioid-induced constipation
Treatment of GI Ulcers
Histamine antagonists, sulfacrate, omeprazole, antacids
Antacids
Neutralize stomach acids, Magnesium Hydroxide, Aluminum hydroxide, Calcium carbonate, Sodium bicarbonate, interfere with absorption of other drugs
Histamine Antagonists
Competitive Inhibitors reducing acid secretion and pepsin, cimetidine, ranitidine, famotidine, nizatidine
Gastric Acid Secretion
CCK at gastrin receptors, paracrine at histamine receptors, Ach at muscarinic receptors
Histamine Antagonist Activity
Ranitidine and nizatidine prokinetic, cimetidine and ranitidine used in calf, ranitidine used in horse
Histamine Antagonist Adverse Effects
Minor, cimetidine inhibits clearance of other drugs
Sucralfate
Dissociates and polymerizes into sticky substance that binds ulcerated mucosa, increases prostaglandins, inactivates pepsin
Proton Pump Inhibitors
Decrease acid secretion, potent and irreversible, prodrug in blood, omeprazole
PPI Use
Support ulcer healing, prevent reflux, administer prior to meal, caution with liver metabolizable drugs
PPI Adverse Effects
Elevated gastrin levels, small intestine bacterial overgrowth, diarrhea in dogs
Synthetic Prostaglandins
Block EP3 receptors on parietal cells to decrease acid secretion, reduces risk of ulcer and hemorrhage from NSAID, misoprostol
Misoprostol
Prevents ulcer, reduces acid secretion, contraindicated in pregnancy
Helicobacter Gastritis Treatment
Antibiotics and PPI
Mucosal Protectants
Produce coating of epithelium that prevents irritation
Mucosal Adsorbents
Prevent absorption of chemical compounds to eliminate them in feces
Kaolin-Pectin
Binds bacterial toxins, changes stool consistency
Pectin
May adsorb other drugs
Mismuth Subsalicylate
Adsorbs bacterial toxins and produces protection, salicylate is absorbed, anti-Helicobacter
Anticholinergic Drugs
Modify motility for the treatment of diarrhea
Stovepipe Effect
Anticholinergics may worsen some types of diarrhea, avoid if diarrhea is infectious
Anticholinergic Adverse Effects
Ileus, dry mouth, urine retention, pupil paralysis, tachycardia, CNS excitement, contraindicated in gastritis and vomiting
N-butylscopolammonium Bromide
Antispasmodic for colic, relax rectum and colon, short duration
N-butylscopolammonium Bromide Adverse Effects
Increase in HR
Opioids
Antisecretory and antimotile, contraindicated in infectious diarrhea
Diphenyloxylate hydrochloride
Administered with atropine, systemic opiate effects can occur
Loperamide hydorchloride
Does not have systemic opiate effects, increases intestinal transit time
Antimicrobials
Should be based on bacterial etiology
Indication of Antibacterial Therapy
Hemorrhagic diarrhea, fever, abnormal WBC count
Tylosin Responsive Diarrhea
Chronic diarrhea in dogs
Sulfasalazine
Treatment of colitis, inhibits prostaglandins to decrease intestinal free radicals
Prednisolone
Suppress autoimmune activity to prevent IBD
Azathioprine
Inhibits activated lymphocytes in severe IBD
Eicosapentanoic Acid
Treats colitis
Anthraquinone
Irritant laxative, inhibits Na/K ATPase, can cause damage to enterocytes
Saline Cathartics
Electrolytes that draw fluid into the bowel, increase peristalsis
Carboxymethylcellulose
Bluk forming, nonabsorbed polysaccharide, attracts water into intestine
Lubricants
Coat stool, increase water content, pass hair balls
Surfactants
Stool Softeners
