Week 5 Upper Gastrointestinal Disorders Flashcards Preview

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Flashcards in Week 5 Upper Gastrointestinal Disorders Deck (22)
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1
Q

. List and explain the 4 defensive factors which protect the stomach and duodenum from self-digestion.

A

Mucus – forms a 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

2
Q

List and explain 5 aggressive factors which predispose the stomach and duodenum to ulcerations.

A

Helicobacter pylori (H. pylori) – gram-negative bacillus which lives between the mucus layer and the mucosa. Produces CO2 and ammonia from urea which damages the mucosa.
NSAIDs – decreases the production 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.

3
Q

What are three mechanisms of action for antacids?

A

Binds gastric acid and forms a neutral salt, inactivates pepsin if pH > 5, and stimulates prostaglandins.

4
Q

How are antacids administered in relation to meals, sleep, or other drugs? If not eating, how often are they given?

A

1 and 3 hrs after meals and at bedtime, 1 hour before another drug, or every 2 hours if not eating

5
Q

Which antacids can cause complications in heart failure and renal disease?

A

Aluminum hydroxide and sodium bicarbonate – heart failure, magnesium hydroxide – CNS toxicity in renal patients

6
Q

How do histamine2 receptor antagonists work?

A

Block H2 receptors on parietal cells which suppress gastric acid secretion and decrease the hydrogen ion concentration in gastric acid.

7
Q

How are histamine2 receptor antagonists administered in relation to meals?

A

May be taken without regard to meals, except take Tagamet with food

8
Q

Which histamine2 receptor antagonist is noted for drug-drug interactions caused by inhibition of hepatic drug-metabolizing enzymes?

A

cimetidine (Tagamet)

9
Q

Which histamine2 receptor antagonist is known for its ability to block androgen effects?

A

cimetidine (Tagamet)

10
Q

Proton-pump inhibitors may decrease the absorption of antifungals by what action?

A

Decreased gastric acid production

11
Q

Proton pump inhibitors are usually given when?

A

Usually given before the first large meal of the day. Some may be given at any time.

12
Q

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?

A

Weeks due to irreversible inhibition. 3-5 days.

13
Q

Why is misoprostol (Cytotec) used?

What are the mechanisms of action?

A

Prevention of NSAID-caused gastric ulcers. Stimulates the secretion of mucus and bicarbonate, vasodilates blood vessels, suppress gastric acid secretion. Replaces prostaglandins.

14
Q

Why is misoprostol (Cytotec) not given during pregnancy?

A

Stimulates uterine contractions.

15
Q

How does sucralfate (Carafate) work? When should it be given?

A

Polymerization and cross-linking occurs when the pH is < 4. It adheres to the crater for 6 hours. Given on an empty stomach.

16
Q

How many hours must elapse between an antacid and sucralfate (Carafate)? Between other drugs and sucralfate (Carafate)?

A

1 hour between an antacid and sucralfate.

2 hours between drugs and sucralfate

17
Q

In order to kill Helicobacter pylori, what combination of drugs is given?

A

2-3 antibiotics with a proton pump inhibitor or histamine-2 receptor antagonist`

18
Q

How does bismuth (Pepto-Bismol) work? What are two common side effects?

A

Disrupts the cell wall of H. pylori, inhibits urease, and keeps H. pylori from adhering to the mucosa. Black tongue and stools.

19
Q

At what pH will pepsin be decreased? Inhibited?

A

pH 5, > pH 6-7

20
Q

What is the preferred drug category for the prevention of NSAID-induced ulcers?

A

Proton Pump Inhibitors

21
Q

What are two signs of gastrointestinal bleeding?

A

Black, tarry stools and coffee-ground vomitus.

22
Q

What is the acid-neutralizing capacity (ANC)?

A

The number of mEq of hydrochloric acid that is neutralized by a given amount of the antacid.