NURS8024 Pharm Exam 1
Gastric acid secretion by parietal cells of the gastric mucosa are stimulated by *** *acetycholine,
histamine, gastrin
Receptor-mediated binding of acetylcholine, histamine, or gastrin results in *** *the activation of
protein kinases, which in
turn stimulates the H+/K+-adenosine triphosphatase (ATPase) proton pump
Gastrin and acetylcholine stimulate release of *** histamine
receptor binding of prostaglandin E2 and
somatostatin diminish *** gastric acid production
Antacids *** weak bases that react with gastric acid to
form water and a salt → diminishing gastric acidity
Reduce pepsin activity - pepsin inactive at a pH >4
Wide variety* in chemical composition, acid-neutralizing capacity, sodium content, palatability, and
price
Acid neutralizing ability* of an antacid depends on its capacity to neutralize gastric HCl and on whether
the stomach is full or empty
• food delays stomach emptying, allowing more time for the antacid to react
Therapeutic uses of antacids *** • Symptomatic relief of peptic ulcer disease (PUD) and
gastroesophageal reflux (GERD)
,• May promote healing of duodenal ulcers, but not
robust evidence for efficacy in Tx of acute gastric
ulcers
• Calcium carbonate preparations
• also used as calcium supplements for the treatment of osteoporosis
Commonly used antacid drugs *** Classes
• Calcium salts: calcium carbonate: Tums/Rolaids
• Sodium bicarbonate: Alka-Seltzer
• Aluminum salts - Aluminum hydroxide: Amphojel; Aluminum carbonate: Basaljel
• Magnesium salts/ magnesium oxide: Milk of Magnesia
• Combination products
• Aluminum hydroxide and magnesium hydroxide (Maalox, Mylanta)
• Alginic acid, magnesium trisilicate, calcium stearate
(Gaviscon)
Adverse effects of antacids *** • Aluminum hydroxide tends to be constipating
• Magnesium hydroxide tends to cause diarrhea
• Binding of phosphate by aluminum-containing antacids → hypophosphatemia
• Sodium bicarbonate → belching and flatulence, potential for systemic alkalosis
• Sodium content of antacids → can be important in pts w/ HTN or CHF
• Excessive intake of calcium carbonate along w/ calcium foods → hypercalcemia
Mucosal Protective Agents *** Cytoprotective compounds
Sucralfate
,Bismuth Compounds
Cytoprotective Compounds *** enhance mucosal protection
mechanisms → preventing mucosal injury, ↓ inflammation, promotes healing of existing ulcers
Sucralfate *** complex of aluminum hydroxide and sulfated sucrose
• Small, poorly soluble molecule
• Polymerizes in stomach acid → binds to injured tissue, forms physical barrier coating over ulcer bed-
impairs diffusion of HCl and prevents degradation of mucus by pepsin and acid
• Accelerates healing of peptic ulcers and ↓ recurrence rate
• Stimulates prostaglandin release, mucus and bicarbonate output
• *BIG drawback.... Must be taken qid• used in long-term maintenance therapy to prevent recurrence
• Requires an acidic pH for activation -should not be administered with H2 antagonists or antacids
• Little of the drug is absorbed systemically, very well tolerated
• Can interfere w/ absorption of other drugs by binding to them
• Does not prevent NSAID-induced ulcers
Bismuth Compounds *** • Coats ulcers → protective layer against acid and pepsin
• May stimulate prostaglandin, mucus, and bicarbonate secretion
• Antimicrobial effect- binds enterotoxins
• reduces stool frequency & liquidity in acute infectious diarrhea
• Causes black stools- harmless
• Avoid in renal insufficiency
In geriatric patients avoid use of *** - antacids that contain magnesium in patients with renal failure
- sodium-containing antacids because of fluid
, retention
Antacids in Pediatrics *** Safety not established in children
Antacids during pregnancy and lactation *** No FDA category established, although antacids
generally are considered safe for use in pregnancy
Antisecretory agents *** Histamine-2 receptor antagonists
Proton pump inhibitors
Examples of Histamine-2 receptor antagonists *** ranitidine, *cimetidine, famotidine, nizatidine
Examples of Proton pump inhibitors *** • omeprazole, esomeprazole
• Lansoprazole, pantoprazole
• rabeprazole
H2 Receptor antagonists *** • MOA
• Acts selectively on H2 receptors in the stomach, blood vessels, and other sites (no effect on H1
receptors)
• Competitively blocks binding of histamine to H2 receptors
• less effective than PPIs against stimulated secretion
• Four drugs: cimetidine*. ranitidine, famotidine, and nizatidine
• Can inhibit > 90% basal, food-stimulated and nocturnal secretion of gastric acid after a single dose
• Main clinical use is to inhibit gastric acid secretion
• particularly effective against nocturnal acid secretion
Gastric acid secretion by parietal cells of the gastric mucosa are stimulated by *** *acetycholine,
histamine, gastrin
Receptor-mediated binding of acetylcholine, histamine, or gastrin results in *** *the activation of
protein kinases, which in
turn stimulates the H+/K+-adenosine triphosphatase (ATPase) proton pump
Gastrin and acetylcholine stimulate release of *** histamine
receptor binding of prostaglandin E2 and
somatostatin diminish *** gastric acid production
Antacids *** weak bases that react with gastric acid to
form water and a salt → diminishing gastric acidity
Reduce pepsin activity - pepsin inactive at a pH >4
Wide variety* in chemical composition, acid-neutralizing capacity, sodium content, palatability, and
price
Acid neutralizing ability* of an antacid depends on its capacity to neutralize gastric HCl and on whether
the stomach is full or empty
• food delays stomach emptying, allowing more time for the antacid to react
Therapeutic uses of antacids *** • Symptomatic relief of peptic ulcer disease (PUD) and
gastroesophageal reflux (GERD)
,• May promote healing of duodenal ulcers, but not
robust evidence for efficacy in Tx of acute gastric
ulcers
• Calcium carbonate preparations
• also used as calcium supplements for the treatment of osteoporosis
Commonly used antacid drugs *** Classes
• Calcium salts: calcium carbonate: Tums/Rolaids
• Sodium bicarbonate: Alka-Seltzer
• Aluminum salts - Aluminum hydroxide: Amphojel; Aluminum carbonate: Basaljel
• Magnesium salts/ magnesium oxide: Milk of Magnesia
• Combination products
• Aluminum hydroxide and magnesium hydroxide (Maalox, Mylanta)
• Alginic acid, magnesium trisilicate, calcium stearate
(Gaviscon)
Adverse effects of antacids *** • Aluminum hydroxide tends to be constipating
• Magnesium hydroxide tends to cause diarrhea
• Binding of phosphate by aluminum-containing antacids → hypophosphatemia
• Sodium bicarbonate → belching and flatulence, potential for systemic alkalosis
• Sodium content of antacids → can be important in pts w/ HTN or CHF
• Excessive intake of calcium carbonate along w/ calcium foods → hypercalcemia
Mucosal Protective Agents *** Cytoprotective compounds
Sucralfate
,Bismuth Compounds
Cytoprotective Compounds *** enhance mucosal protection
mechanisms → preventing mucosal injury, ↓ inflammation, promotes healing of existing ulcers
Sucralfate *** complex of aluminum hydroxide and sulfated sucrose
• Small, poorly soluble molecule
• Polymerizes in stomach acid → binds to injured tissue, forms physical barrier coating over ulcer bed-
impairs diffusion of HCl and prevents degradation of mucus by pepsin and acid
• Accelerates healing of peptic ulcers and ↓ recurrence rate
• Stimulates prostaglandin release, mucus and bicarbonate output
• *BIG drawback.... Must be taken qid• used in long-term maintenance therapy to prevent recurrence
• Requires an acidic pH for activation -should not be administered with H2 antagonists or antacids
• Little of the drug is absorbed systemically, very well tolerated
• Can interfere w/ absorption of other drugs by binding to them
• Does not prevent NSAID-induced ulcers
Bismuth Compounds *** • Coats ulcers → protective layer against acid and pepsin
• May stimulate prostaglandin, mucus, and bicarbonate secretion
• Antimicrobial effect- binds enterotoxins
• reduces stool frequency & liquidity in acute infectious diarrhea
• Causes black stools- harmless
• Avoid in renal insufficiency
In geriatric patients avoid use of *** - antacids that contain magnesium in patients with renal failure
- sodium-containing antacids because of fluid
, retention
Antacids in Pediatrics *** Safety not established in children
Antacids during pregnancy and lactation *** No FDA category established, although antacids
generally are considered safe for use in pregnancy
Antisecretory agents *** Histamine-2 receptor antagonists
Proton pump inhibitors
Examples of Histamine-2 receptor antagonists *** ranitidine, *cimetidine, famotidine, nizatidine
Examples of Proton pump inhibitors *** • omeprazole, esomeprazole
• Lansoprazole, pantoprazole
• rabeprazole
H2 Receptor antagonists *** • MOA
• Acts selectively on H2 receptors in the stomach, blood vessels, and other sites (no effect on H1
receptors)
• Competitively blocks binding of histamine to H2 receptors
• less effective than PPIs against stimulated secretion
• Four drugs: cimetidine*. ranitidine, famotidine, and nizatidine
• Can inhibit > 90% basal, food-stimulated and nocturnal secretion of gastric acid after a single dose
• Main clinical use is to inhibit gastric acid secretion
• particularly effective against nocturnal acid secretion
