Gastrointestinal Agents

♦︎ gastrointestinal agents – used to treat disorders of the stomach and/or the intestines ♦︎ include - enzymes - antidiarrheals - antiemetics - anti-ulcer agents - laxatives - stool softeners

♦︎ stomach lies in the ULQ of the abdomen between the lower end of the esophagus and the beginning of the small intestine (duodenum) ● mechanically and chemically breaks down food – (HCl and pepsinogen) forming chyme (semi-fluid liquid) ● peristalsis (wave-like motion) moves food through the digestive tract ♦︎ the small and large intestine make up ~28ft bowel ● most food absorption occurs in the small intestine ● large intestine absorbs water and connects to the rectum and anus for waste (stool) elimination

♦︎ the GI system (alimentary canal) and its accessory organs play a major role in normal body function ● dysfunction may require immediate attention – drug therapy, medical or surgical intervention ● preventative care and early detection of pathology encouraged

Enzymes ♦︎ pepsin – normally present gastric enz – breaks down protein ♦︎ in the absence of pepsin, proteolytic enz from the pancreas that work in the small intestine can still break down protein to amino acids ♦︎ some conditions (cystic fibrosis / chronic pancreatitis) may require enz therapy – pancreatin or pancrelipase ♦︎ malabsorption conditions (steatorrhea) where fat is inadequately digested and excreted in the stool - may be treated with pancrelipase

Antidiarrheals ♦︎ diarrhea – condition of frequent, watery stools (decrease in intestinal water absorption, increased secretion of electrolytes or an excessive amount of mucous production) – may result from microorganisms (viral / bacterial), drug or stress reaction ♦︎ antiperistalsis drugs – slow the movement of intestinal contents (increase water and electrolyte absorption) ● Immodium (loperamide) / Lomotil (diphenoxylate + atropine) ♦︎ secretion inhibitor – blocks the secretion of stomach acid and has antibacterial properties ● Pepto-Bismol (bismuth subsalicylate) ♦︎ infectious diarrhea antibiotics (metronidazole and vancomycin) may be indicated

Antiemetics ♦︎ treats condition of nausea and vomiting – usually a symptom or side effect of some other condition ● food / drug allergy or reaction, pregnancy, stress / anxiety, exhaustion, viral / bacterial infection, cancer ♦︎ treatment is to reduce the hyperactivity of stimuli receptors and lower the impulse rate – dehydration and electrolyte imbalance are major concern with prolonged vomiting ● Compazine (prochlorperazine)

Antacid / Antiulcer Agents ♦︎ generally composed of inorganic salts (calcium carbonate, aluminum hydroxide, magnesium hydroxide) – neutralize existing acid in the stomach ♦︎ indicated at the onset of hypergastric activity – pain relieving, short acting and not strong enough for undiagnosed ulcers ● Maalox, Gaviscon, Mylanta, Rolaids, Tums histamine receptor agonist ♦︎ inhibits the secretion of gastric acid by blocking the effects of histamine ● Zantac (ranitidine), Pepcid (famotidine)

GERD (gastroesophageal reflux disease) / peptic ulcer ♦︎ caused by hypergastric acidity that erodes tissue in localized areas of the esophagus, stomach and intestines ♦︎ most are benign and produce mild symptoms of discomfort – more serious extend to underlying layers of connective tissue and smooth muscle (bleeding) ♦︎ treatment includes bland diet and PPI (proton pump inhibitor) ♦︎ proton pump inhibitors (PPIs) reduce the production of acid by blocking the enzyme in the wall of the stomach that produces acid ● Prilosec (omeperazole) – now OTC ● Prevacid (lansoprazole) – now OTC ● AcipHex (rabeprazole) ● Nexium (esomeprazole) – now OTC (“purple pill”) ● Protonix (pantoprazole(

laxatives and stool softeners ♦︎ commonly prescribed to treat constipation – condition of dehydrated stool, infrequent bowel movements (often painful and difficult) ♦︎ change in diet, fluid intake and activity level laxatives ♦︎ promote defecation without stress or pain ♦︎ bulk forming – swell when mix with intestinal contents (increase water) ♦︎ stimulant – irritate the lining and nerves of the intestine to move stool through the bowel ♦︎ saline – rapidly promote watery stools by drawing water into the intestine ♦︎ osmotic – increase stool water content through osmosis stool softeners (emollient laxative) ♦︎ Colace (docusate sodium) – promotes the mixing of fatty and watery intestinal substances to soften the stool