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22 Cards in this Set
- Front
- Back
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List and explain the 4 defensive factors which protect the stomach and duodenum from self-digestion
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Mucus- forms barrier to protect underlying cells from gastric acid and pepsin
Bicarbonate- neutralizes any acid which penetrates the mucus Blood flow-maintains integrity or health of the mucosa Prostaglandins - stimulates mucus and bicarbonate, vasodilates blood vessels, suppresses gastric secretion |
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List and explain 5 aggressive factors which predispose the stomach an duodenum to ulcerations
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Helicobacter pylori (H. pylori)- gram negative bacillus which lives between the mucus layer and the mucosa. prod CO2 and ammonia from urea which damages the mucosa
NSAIDS - decreases the prod of prostaglandins which decreases blood flow, decreases bicarbonate and mucus secretion, and increases gastric acid Gastric acid - injures cells of the mucosa and activates pepsin Pepsin - breaks down protein of the gut wall Smoking - delays healing of ulcers and increases risk of recurrence |
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What are three mechanisms of action for antacids?
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Binds gastric acid and forms a neutral salt, inactivates pepsin if pH > 5, and stimulates prostaglandins
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How are antacids administered in relation to meals, sleep, or other drugs? if not eating, how often are they given?
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1 and 3 hours after meals and at bedtime, 1 hour before another drug, or every 2 hours if not eating
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Which antacids can cause complications in heart failure and renal disease?
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Aluminum hydroxide and sodium bicarbonate-heart failure, magnesium hydroxide-CNS toxicity in renal patients
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How do histamine (2) receptor antagonists work?
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Block H(2) receptors on parietal cells which suppress gastric aced secretion and decrease the hydrogen ion concentration in gastric acid
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How are histamine (2) receptor antagonists administered in relation to meals?
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May be taken w/o regard to meals except take Tagamet w/food
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Which histamine (2) receptor antagonist is noted for drug-drug interactions caused by inhibition of hepatic drug-metabolizing enzymes?
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Cimetidine (Tagamet)
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Which histamine (2) receptor antagonist is known for its ability to block androgen affects?
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Cimetidine (Tagamet)
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Proton-pump inhibitors may decrease the absorption of antifungals by what action?
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Decreased gastric acid production
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Proton pump inhibitors are usually given when?
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Usually given before the first large meal of the day. Some may be given at any time
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How long does it take for full recovery of the H+, K+-ATPase pump after stopping a proton pump inhibitor? Why? How long for partial recovery?
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Weeks due to irreversible inhibition. 3-5 days
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Why is misoprostol (Cytotec) used? What are the mechanisms of action?
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Preventions of NSAID-caused gastric ulcers. Stimulates the secretion of mucus and bicarbonate, vasodilates blood vessels, suppress gastric acid secretion. Replaces prostaglandins
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Why is misoprostol (Cytotec) not given during prego?
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Stimulates uterine contractions
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How does sucralfate (Carafate) work? When should it be given?
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Polymerization and cross-linking occurs when the pH is < 4. It adheres to the crater for 6 hours. Given on an empty stomach
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How many hours must elapse between an antacid and sucralfate (Carafate)? Between other drugs and sucralfate (Carafate)?
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1 hour between an antacid and sucralfate.
2 hours between drugs and sucralfate |
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In order to kill Helicobacter pylori, what combo of drugs is given?
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2-3 antibiotics w/ a proton pump inhibitor or histamine -2 receptor antagonist
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How does bismuth (pepto-bismol) work? What are 2 common side effects>
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Disrupts the cell wall of H pylori, inhibits urease, and keeps h. pylori from adhering to the mucosa. side effects = black tongue and stools
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At what pH will pepsin be decreased? inhibited?
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pH 5; > pH 6-7
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What is the preferred drug category for the prevention of NSAID-induced ulcers?
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Proton Pump Inhibitors
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What are 2 signs of gastrointestinal bleeding?
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Black, tarry stools, and coffee-ground vomitus
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What is the acid-neutralizing capacity (ANC)?
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the number of mEq of hydrochloric acid that is neutralized by a given amount of the antacid
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