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This Concept Map, created with IHMC CmapTools, has information related to: GI Drugs, GI Drugs Laxatives Saline (Osmotic) MAGNESIUM SULFATE (Epsom) MgOH, NaK, PO4 -ions slowly absorbed ->lots of fluid enters colon ->distension->peristalsis Use-evacuate colon for procedure, GI Drugs Peptic Acid Disorders Prostaglandins MISOPROSTOL (Cytotec) Alprostadil -PGE1 analog MOA-inhibit H+, gastrin secretion -inhibit pepsin secretion -stim mucus, HCO3 secretion -epith cells -increase mucosal blood flow -decrease cAMP->hist increases Use: prevent/Tx ulcers when on long-term NSAIDs -or failed H2 blocker ADRs-N/V/D, HA, stim uterine contractions (uterotonic), GI Drugs Laxatives Laxatives-mild ->soft, formed stool Cathartics-harsh ->fluid evacuation, GI Drugs Anti-Flatulence SIMETHICONE (Gas-X, Flatulex) -de-foaming action, H2 receptor BLOCKERS CIMETIDINE (Tagamet) MOA-inhibit H+, pepsin secretion Use: Ulcers-combo w/ H. pylori Tx -Z-E syndrome-high dose -dyspepsia, GERD ADRs-HA, dizziness, diarrhea -high dose-reduce libido, sperm -inc'd PRL secretion, gynecomastia -menstrual d/o, CNS w/ liver dz -renal failure in elderly, young Inhibits CYP-2C9, 3A4, 2D6: diazepam, theophylline, propranolol, pentobarb, lidocaine Others FAMOTIDINE (Pepcid AC) -slowly reversible -MOST potent H2 blocker -onset w/in 1 hr -no anti-androgen ADRs -fewer drug interactions, GI Drugs Laxatives Stool Softeners (Emollient) DOCUSATE-surfactant -oral (bitter), rectal -minimal lax effect, just soft MOA-decrease surface tension -inhibit Na/K ATPase -increase cAMP, cell dmg LIQUID PETROLATUM -lubricate mass, prevent dehydration -tasteless, odorless -leaks past anal sphincter GLYCERIN, MINERAL OIL, GI Drugs Peptic Acid Disorders Inhibit Proton Pump: LANSOPRAZOLE (Prevacid) OMEPRAZOLE (Prilosec) -prodrug MOA-oxidize -SH group in pump ->inhibit acid secretion by any stimulus -irreversible Use: DOC for Zolliger-Ellison -most effective Rx for GERD -ulcers-almost as effective as H2 ADRs: gastrin-producer hypertrophy -constipation, skin rash, elevated LFTs Inhibit P450-dec'd benzo, warfarin, phenytoin clearance, GI Drugs Antidiarrheals Kaolin/Pectin (Kaopectate) -water binder, thickener, GI Drugs Laxatives ADRs Cathartic Colon Syndrome -dilated colon, hypomotile, atrophic mm layer Addiction-esp WOMEN Hypokalemia-Na+ loss in stool ->retain Na in kidney, lose K Malabsorption of CHO, fat, vit, Ca Liver-DOCUSATE toxic to hep'cytes, GI Drugs Antidiarrheals OPIUM derivatives (paregoric) -DIPHENOXYLATE-demerol analog -Diphenoxine-5x more potent -CNS ADRs -LOPERAMIDE (Imodium) -MOST EFFICACIOUS -sustained sm mm contraction ->no peristalsis -inhibit ACh at bowel via mu rec -increase electrolyte xport -enhance Na+, Cl- absorption -inhibit secretion Blocked by Naloxone, GI Drugs Peptic Acid Disorders BISMUTH SUBSALICYLATE (Pepto Bismol) MOA-inhibit pepsin activity -bactericidal against H. pylori ADRs-few, unpleasant taste -TURNS STOOL BLACK, Nonselective Musc Antags -Atropine-like PROPANTHELINE-prodrug METHANTHELINE ADRs-tachy, dry mouth, blurry vision, abd pain, reduced swallowing Contraind: glaucoma, obstructive uropathy, arrhythmias, myas gravis M1 selective PIRENZEPINE (Canada) TELENZEPINE -stomach effects -hydrophilic-no CNS -OK w/ glaucoma ADRs-blurry vision, H2 receptor BLOCKERS CIMETIDINE (Tagamet) MOA-inhibit H+, pepsin secretion Use: Ulcers-combo w/ H. pylori Tx -Z-E syndrome-high dose -dyspepsia, GERD ADRs-HA, dizziness, diarrhea -high dose-reduce libido, sperm -inc'd PRL secretion, gynecomastia -menstrual d/o, CNS w/ liver dz -renal failure in elderly, young Inhibits CYP-2C9, 3A4, 2D6: diazepam, theophylline, propranolol, pentobarb, lidocaine Others RANITIDINE (Zantac) -furan ring, not imidazole -5x more potent -no PRL or anti-androgen ADRs Nizatidine-similar -higher bioavailability -shorter T1/2 -no CYP450 inhibition, GI Drugs Peptic Acid Disorders Gastrin-not approved in US Proglumide -receptor blocker Sulpiride-anti-DA drug -inhibits secretion, GI Drugs Peptic Acid Disorders H2 receptor BLOCKERS CIMETIDINE (Tagamet) MOA-inhibit H+, pepsin secretion Use: Ulcers-combo w/ H. pylori Tx -Z-E syndrome-high dose -dyspepsia, GERD ADRs-HA, dizziness, diarrhea -high dose-reduce libido, sperm -inc'd PRL secretion, gynecomastia -menstrual d/o, CNS w/ liver dz -renal failure in elderly, young Inhibits CYP-2C9, 3A4, 2D6: diazepam, theophylline, propranolol, pentobarb, lidocaine, GI Drugs Laxatives Anthraquinones EMODIN ALKALOIDS -inhibit villus Na/K ATPase ->water accum in lumen ADRs-colic, GI Drugs Peptic Acid Disorders Non-systemic Antacids -poorly absorbed ->no systemic alkalosis CALCIUM CARBONATE -chalky, rapid, long DOA -can->rebound acidity -due to Ca++ on antrum ->gastrin, H+ secretion -some Ca++ absorbed MAGNESIUM HYDROXIDE -most potent in use -can->diarrhea -kidney fcn important, GI Drugs Laxatives CASTOR OIL -> active ricinoleic acid MOA-inhibit Na/K ATPase ->water in lumen -increase PGE2->cAMP ->peristalsis -cathartic -awful taste, GI Drugs Peptic Acid Disorders Physiology Gastic Acid agonists: Histamine, ACh, gastrin, GI Drugs Antidiarrheals BISMUTH SALTS (Pepto-Bismol) -for TRAVELER'S DIARRHEA -absorb E. coli enterotoxin -inhibit PG production, cAMP ->black tongue, stool -inhibit secretions -can -> IMPACTION