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Pharmacology Unit 6 > Gastrointestinal Drugs I > Flashcards

Flashcards in Gastrointestinal Drugs I Deck (35)
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1

Basic pathophysiology leading to ulcers?

 

  1. Increased acid
  2. Decreased mucosal resistance

2


Three receptors on the parietal cell? Overall effect?

 

  1. Histamine
  2. Gastrin
  3. ACh

Stimulate K+/H+ ATPase activity

3


By what mechanism does Histamine work to increase stomach acidity?


Histamine hits receptor that causes an increase in cAMP and K+/H+ action

4


Describe the mechanism of action of gastrin to increase acidity of stomach. ACh?


Both hit their respective receptors and cause an influx of Ca2+ activating K+/H+ ATPase

5


Where do Gastrin and ACh come from, respectively?

 

  • Gastrin - antrum
  • ACh - Vagal inputs

6


What are the goals of pharmacologic intervention for ulcer Tx?

 

  1. Relieft of Syx, especially pain
  2. Promotion of healing
  3. Prevention of complications such as perforation, hemorrhage, or scar formation
  4. Prevention of recurrence

7


Tx plan for ulcer?

 

  1. Neutralize acid
  2. Decrease acid production
  3. Increase mucosal resistance

8


Antacid neutralizing efficacy based on:

  1. The neutralizing power of the antacid
  2. The degree or rate of acid secretion
  3. Rate of stomach emptying

9


What are the active ingredients of antacid preparations?

 

  • CaCO3
  • NaHCO3
  • Mg(OH)2 and MgCO3
  • Al(OH)2

10


Mjr SE of CaCO3


Milk-alkali syndrome, nephrocalcinosis, rebound acidity, digitalis antagonism

11


SE of NaHCO3


Systemic alkalosis and therefore rarely used

12


SE of Mg(OH)2?


Diarrhea, Hypokalemia, Hypermagnesemia, complexing of enteric iron and therefore iron deficiency

13


Why is Al(OH)2 less likely to cause electrolyte imbalances?


Al precipitates with enteric phosphate and is not absorbed in the gut

14


Adverse effects of Al(OH)2?


Constipation, Phosphate depletion and sequelae

15


What would an equivalent procedure be to using an Anticholinergic agent?


Vagotomy

16

What are the SE of anticholinergic agents?

  • Dryness of mouth
  • Blurred vision
  • Atony of the bladder
  • Constipation
  • Drowsiness
  • Mental Confusion

17

What are the anticholinergic drugs?


Atropine, Prpantheline, Metantheline bromide

18

What are the two big guns of the H2 blocker family? The lesser kids?

  • Cimetidine and ranitidine
  • Famotidine
  • Nizatidine

19


What is an important consideration when prescribing an H2 blocker?


Cimetidine and ranitidine bind to CP450 interfering with the metabolism of drugs such as theophylline, warfarin, dilantin, or lidocaine

20

What are the H+/K+ ATPase inhibitors?

 

  • Omeprazole
  • Lansoprazole
  • Rabeprazole
  • Esomeprazole
  • Pantoprazole
  • Dexlansoprazole

21


Which H+/K+ ATPase inhibitor has the best bioavailability?


Lansoprazole

22


Which H+/K+ ATPase inhbitor has the greatest P450 inhbition? Moderate? Least?

 

  • Most - Omeprazole
  • Moderate - Rabeprazole
  • Least - Pantoprazole

23


Which H+/K+ ATPase inhibitor has the greatest bioavailability and least P450 inhibition?


Pantoprazole

24


What are the advantages of H+K+ ATPase inhibitors over the H2 inhibitors?

  • Better pain relief
  • Faster healing of ulcer
  • Heal H2 antagonist refractory ulcers

25


SE of HKAIs?

 

  • Gynecomastia
  • P450 inhibition and delayed metabolism of diazepam, warfarin, dilantin
  • Gastric hyperplasia in humans

Not recommended for long term Tx

26


What are two exogenous agents that can cause ulcers?

 

  • NSAIDS
  • H. Pylori

27


MOA of Bismuth Salts?


In acidic environment, salts precipitate and coat ulcer

28


MOA of sucralfate?


Al(OH)2 complex of sucrose activated in acidic environment and binds to ulcer

29


Which ulcer-coating agent is most efficacious?


Bismuth salts

30

In a patient taking chronic NSAIDs, what would be  a good medication to prescribe to prevent ulcers?


Presribe misoprostol to compensate for prostaglandin defciency due to NSAIDs.