Gastointestinal Pharmacology Flashcards Preview

Pharmacology Quiz 4 > Gastointestinal Pharmacology > Flashcards

Flashcards in Gastointestinal Pharmacology Deck (53)
Loading flashcards...
1

What is the pathogenesis of gastroduodenal ulcers?

Excess gastric acid secretion, breakdown of mucosal cytoprotection, Helicobacter pylori infection

2

What are the goals of ulcer treatment?

reduce ulcerogenic factors, enhance defensive factors, or eradicate any infectious causes

3

What are pro-ulcerogenic factors?

Acids (HCl, VFA, bile acids), pepsin, infections

4

What are antiulcerogenic factors?

mucosal cytoprotection, epithelial renewal, external protection

5

How does one increase the gastric pH to greater than 4 to promote healing?

H2-Histamine receptor blockade, stimulation of gastric PGE receptors, gastric H+-K+-ATPase inhibition (proton pump inhibitors)

6

Famotidine

H2-Histamine antagonist, decreases acid secretion which decreases pepsin. As treatment continues effectiveness decreases due to an increased secretion of gastrin. Low oral biovalibility and renal clearance

7

What are examples of H2-histamine antagonists?

famotidine, ranitidine, cimetidine

8

What are the side effects and indications of H2-histamine antagonist?

Renal disease patients need lower dose, treatment of ulcers due to gastritis, stress, NSAID terapies, gastrinomas

9

Misoprostil

PGE analogue, po administration, needs frequent administration due to rapid hepatic metabolism. Decreases acid secretion stimulated by histamine or gastrin. Less effective than H2-HR antagonists or PPI, increases gastric cytoprotection

10

How do PGE and PGI promote cytoprotection?

Mucus production (coats surface of the gastric mucosa), bicarb production (neutralizes HCl), intrinsic mucosal barrier (resist back-diffusion of acid), and gastric blood flow (flushes away acid, prevents buildup, maintains tissue pH in normal range)

11

Indications/side effects/contraindications of misoprostil?

NSAIDs-induced ulcers, increased mast cell influx. Side effects include diarrhea due to prokinetic action. Contraindications include IBD, pregnancy

12

What is an example of a proton pump inhibitor?

Omeprazole

13

What is the action of proton pump inhibitors?

Irreversibly inactivate H+/K+ ATPase, so effects extend longer than the drug's presence in the body. Reduce acid secretions

14

Omeprazole

Proton pump inhibitor. Oral paste that is a weak base that decreases the release of HCl

15

Sucralfate

Binds to ulcerated tissue to form a seal after oral administration, heals existing ulcers not prevent new ones. Short duration of action. Binds and inactivates bile acids, increases local prostanoid formation.

16

Antacids

Either systemic or non-systemic, non-systemic only affects stomach. Maalox and Mylanta examples. Relieve clinical signs, no healing.

17

Na or Ca carbonate antacids onset

rapid

18

Mg salts (sulfate, hydroxide) onset

intermediate with laxative effect

19

all hydroxide antacids onset

slow

20

What is the best type of drug to use to treat an ulcer: PPIs, H2-histamine antagonists, or cytoprotectants?

PPIs

21

What are examples of locally-acting emetic agents?

warm water, sodium chloride, 3% hydrogen peroxide, syrup of ipecac (emetine akaloid substance)

22

Apomorphine

centrally acts on D2 dopamine receptors, produces vomiting in 2-10 minutes

23

Xylazine

simulates alpha2-adrenergic receptors to produce emesis in cats

24

Indications of anti-emetic drugs

motion sickness, uremia, liver disease, cancer chemo, parvo, trauma

25

Famotidine

H2-histamine antagonist that lessens irritating effects of acid on the stomach

26

muscarinic acetylcholine antagonist anti-emetic effects

decrease vagal afferent transmission to vomiting center to decrease vomiting

27

kaolin-pectin and other coating agents anti-emetic efficacy

not very effective

28

Metoclopramide

Simulate gastric motility, block CNS dopamine receptors and 5-HT3 receptors

29

Action of diphenhydramine, meclizine

may reduce motion sickness by blocking histamine and muscarinic cholinergic receptors

30

Ondanestron

blocks type three serotonin receptors on gastric vagal fibers and are effective at inhibiting emesis in dogs associated with chemo or parvo