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61 Cards in this Set
- Front
- Back
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What are:
atropine scopolamine propantheline telenzipine pirenzipine |
-competitive inhibitors of acetylcholine
-reduce basal secretion of gastric acid |
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What side effects are associated with anticholinergic agents?
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-dry mouth
-increased heart rate -blurred vision |
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What are:
cimetidine ranitidine famotidine nizatidine |
-histamine H2-receptor antagonists
-reduce basal and stimulated acid secretion |
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What side effects are associated with histamine H2-receptor antagonists?
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relatively rare, often less than placebo groups!
-increase prolactin → gynecomastia -mental confusion -agranulocytosis -(cimetidine only) inhibits P450 |
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What are:
lansoprazole omeprazole |
-permanently inhibit H+ K+ ATPase
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How are H+ K+ ATPase inhibitors activated? What is their mechanism of action?
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converted in acidic environment of parietal cell canaliculi to sulfenamides → interact covalently with sulfhydryl groups in extracellular domain of proton pump
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What side effects are associated with H+ K+ ATPase inhibitors?
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-nausea
-diarrhea -inhibit p450 -drug interactions with phenytoin, diazepam, and warfarin |
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How do prostaglandins improve duodenal ulcers?
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-nonspecific reduction of basal and stimulated acid output
-shortens healing time |
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What is the mechanism of action of sodium bicarbonate?
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neutralizes acid:
NaHCO3 + HCl = NaCl + H2O + CO2 |
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What side effects are associated with sodium bicarbonate?
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-systemic alkalosis (milk-alkali syndrome)
-acid rebound/secretion (due to distension of stomach) -alkalination of urine (avoid in patients with renal insufficiency) |
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What is the mechanism of calcium carbonate?
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-acid neutralizing agent:
CaCO3 + 2 HCl = NaCl + H2O + CO2 |
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What side effects are associated with calcium carbonate?
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-hypercalcemia (patients with milk-alkali syndrome)
-positive phosphate balance -reduces dietary fat absorption -acid rebound -nausea -constipation |
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What is the mechanism of aluminum antacids?
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-acid neutralizing agent:
Al(OH)3 + 3HCl = AlCl3 + 3 H2O -slow acting, not absorbed |
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What side effects are associated with aluminum antacids?
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-constipation
-form aluminum phosphate → hypophosphaturia -reduces bioavailability of pepsin, bile salts, indomethacin, tetracycline, isoniazid, benzodiazepines, chlorpromazine, barbiturates, etc. |
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What is the mechanism of magnesium antacids?
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-acid neutralizing agent:
Mg(OH)2 + 2 HCl = MgMCl2 + 2 H2O -poorly soluble |
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What side effect is commonly associated with magnesium antacids?
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osmotic diarrhea
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What is magnesium trisilicate?
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-non systemic, non reversible slow reacting antacid
-rarely elevates the pH above 3 |
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What byproduct is formed with usage of magnesium trisilicate? What does it do?
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-SiO2
-adsorbs pepsin, dietary protein, and drugs (digoxin, iron, benzodiazepines, phenothiazine, antimuscarinic drugs) |
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How do anti-inflammatory agents such as ACTH, cortisone, aspirin, and indomethacin contribute to formation of peptic ulcers?
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reduce secretion of mucin
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What is carbenoxolone sodium?
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mucosal barrier fortifying agent:
-acts locally on gastric mucosa to inhibit back diffusion of hydrogen ions → increased mucin secretion |
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What side effects are associated with carbenoxolone sodium?
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aldosterone-like activity →
-water/salt retention -hypokalemia (use with thiazide diuretic and potassium) |
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What is misoprostol?
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-prostaglandin E analog
-mucosal barrier fortifying agent -moderately effective in treating duodenal/gastric ulcers -prevention of ulcers in patients taking NSAIDS |
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What is a side effect of misoprostol?
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potential abortificant
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What is sucralfate? What conditions are necessary for it to be effective?
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-mucosal barrier fortifying agent
-aluminum sucrose sulfate: binds to necrotic ulcer tissue → barrier to acid and pepsin -requires elevated pH |
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How do bizmuth compounds treat peptic ulcers?
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-antibacterial against H. pylori
-cytoprotective effects (enhanced secretion of mucus, accumulation in ulcerations) -no substantial capacity to neutralize gastric acid |
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What side effects are associated with bismuth compounds (colloidal bismuth subcitrate, bismuth subsalicylate)?
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-reaction of bismuth with bacterial H2S = bizmuth sulfide → black color of oral cavity and feces
-salicylate levels comparable to aspirin use → possibility of Reye's syndrome |
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What is the role of metronidazole in the treatment of peptic ulcers?
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antibacterial against H. pylori
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What is the role of tetracycline in the treatment of peptic ulcers?
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antibacterial against H. pylori
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What is the role of amoxicillin in the treatment of peptic ulcers?
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antibacterial against H. pylori
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What is the role of clarithromycin in the treatment of peptic ulcers?
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antibacterial against H. pylori
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What is the role of antacids in the treatment of gastroesophageal reflux?
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-direct effect: raising pH → increase lower esophageal sphincter pressure
-indirect effect: decrease gastrin (?) |
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What is the role of cimetidine in the treatment of gastroesophageal reflux?
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-indirect effect: inhibit acid secretion
-no direct effect on lower esophageal sphincter pressure |
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What is the role of cholinergic drugs (such as bethanechol) in the treatment of gastroesophageal reflux?
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-acts selectively on smooth muscle of GI tract → increases lower esophageal sphincter pressure
-reduces esophageal reflux -diminishes acid clearance time from esophagus -reduces inflammatory changes in esophagus due to reflux |
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What is metoclopramide and what does it do?
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-derivative of procainamide - structural antagonist of D2 dopamine and 5-HT3
-depresses vomiting center by blocking dopamine/5-HT3 receptors -stimulates gut motility |
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What are the GI effects of metoclopramide?
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-increased resting muscle tension of lower esophageal sphincter, gastric fundus, antrum, and small intestine
-improve gastric emptying, gastroduodenal coordination, and shorten transit through small bowel -no effect on acid secretion |
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What are the clinical uses of metoclopramide?
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-used when attempts to intubate the duodenum have failed, or with delayed gastric emptying (radiographic examination)
-in anesthesia for emergencies, labor, delivery -chronic GERD -improve effectiveness of oral medication in patients with gastroparesis/ gastric stasis -relieves early satiety, epigastric discomfort, nausea, vomiting in patients unable to digest solid food -motor abnormalities of the gut in which cholinergic activity is diminished but not abolished |
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What side effects are associated with metoclopramide?
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-nervousness
-restlessness -drowsiness -blocks dopamine secretion of aldosterone secretion -stimulation of prolactin secretion → galactorrhea |
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How are opioids used in treatment of GI problems?
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-most effective nonspecific antidiarrheal agent
-act via morphine content to cause decrease in acid secretion and gut motility → increases water/electrolyte absorption -75% have constipation |
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What are diphenoxylate and loperamide?
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-nonspecific antidiarrheal agents
-synthetic narcotics (meripedine congeners) -almost insoluble, not absorbed -slow GI motility -may be counteracted by atropine |
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What is the role of anticholinergic agents in treatment of diarrhea?
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nonspecific antidiarrheal agent:
decrease intestinal tone and peristalsis |
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How do bismuth salts, aluminum silicate, aluminum hydroxide, pectin, activated charcoal, amd magnesium trisilicate improve diarrhea?
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nonspecific antidiarrheal agent:
absorb undesirable substances (toxins, bacteria, viruses) from solution |
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How do dietary fiber, bran, methyl/carboxymethyl cellulose, and psyllium seed derivatives improve diarrhea?
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nonspecific antidiarrheal agent:
hydrophilic substances which absorb water and bile salts |
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How do lactobacillus cultures improve diarrhea?
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nonspecific antidiarrheal agent:
restore normal bowel flora when diarrhea is caused by pathogenic organism |
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How do adrenal corticosteroids (such as hydrocortisone and prednisone) improve diarrhea?
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specific antidiarrheal agent:
-used in treatment of inflammatory bowel disorders (but does not cure infection and disorder may still progress) |
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How do colestipol and cholestyramine improve diarrhea?
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-specific antidiarrheal agent
-anion exchange resins -bind bile salts in the colon (not supposed to be there) and remove them |
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What side effects may be associated with colestipol and cholestyramine?
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may bind compounds (such as phenylbutazone, chlorothiazide, pentobarbital, digitalis, tetracycline) and interfere with their absorption from GI tract
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How do natural/semisynthetic polysaccharide derivatives such as pectin and bran function as laxatives?
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bulk producers:
-absorb water -increase volume of intestinal content → increase intraluminal pressure → stimulation of reflex peristalsis and defecation |
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How do magnesium salts act as laxatives?
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bulk producers:
-nonabsorbable salts which absorb water from the intestine to maintain isotonic concentration -increase volume of intestinal content → increase intraluminal pressure → stimulation of reflex peristalsis and defecation |
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How do dioctyl sulfosuccinate and docusate act as laxatives?
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fecal softeners:
-anionic surfactants -lower surface tension → allow water and lipids to penetrate fecal mass and soften it |
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How do mineral oil and olive oil act as laxatives? What is one of the possible side effects?
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fecal softeners:
-lubricants (mix with fecal mass and act as emulsifying agents to soften it) -may interfere with absorption of fat soluble vitamins |
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How do diphenylmethane, phenolphthalein and bisacodyl act as laxatives?
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-cathartics
-act on colon to stimulate submucosal myenteric plexus -alter water and electrolyte fluxes in intestine |
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What side effects are associated with diphenylmethane, phenolphthalein and bisacodyl?
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-laxatives: possible fluid and electrolyte deficit
-possible allergic reaction to phenolphthalein |
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How do Senna, Cascara Segrada, and Danthron act as laxatives? What conditions are necessary for them to work effectively?
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-cathartics (anthaquinones)
-act on large intestine, alter water and electrolyte fluxes by inducing changes in motility and net absorption of water -intestinal microflora must release active constituents |
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How does castor oil act as a laxative?
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-cathartic: acts on small intestine to reduce net intestinal absorption of water and shorten intestinal transit time
-triglyceride of rinoleic acid |
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What are the 4 categories of hyposecretory agents used in peptic ulcer treatment?
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-anticholinergic agents
-histamine H2-receptor antagonists -inhibitors of H+ K+ ATPase -prostaglandins |
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What are 5 types of commonly used acid neutralizing agents?
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systemic:
-sodium bicarbonate -calcium carbonate -magnesium antacids nonsystemic: -aluminum antacids -magnesium trisilicate |
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what are the 4 types of mucosal barrier fortifying agents?
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-anti-inflammatory agents
-carbenoxolone sodium -prostaglandins -sucralfate |
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What are the 4 main categories of drugs that affect the esophagus?
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-antacids
-H2 receptor antagonists -cholinergic drugs -metoclopramide |
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What are the 6 types of nonspecific antidiarrheal agents?
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-opiates
-synthetic narcotics -anticholinergic agents -adsorbents (bismuth, aluminum, etc.) -absorbents (fiber, bran, etc.) -probiotics |
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What are the 3 categories of specific antidiarrheal agents?
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-antibiotics, antifungal, antiparasitics
-adrenal corticosteroids -anion exchange resins |
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What are the 3 main categories of laxatives?
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-bulk producers (hydrophilic, saline)
-fecal softeners (anionic surfactants, lubricants) -stimulants/cathartics |
