Acid Controlling Drugs

Question 1

Where are parietal cells located and what do they produce?

Answer 1

Parietal Cells are located in the stomach and they produce HCl

Question 2

Where are Chief Cells located and what do they produce?

Answer 2

Chief Cells are located in the stomach and they produce pepsingogen (a precursor to pepsin).

Question 3

What is the role of pepsin in the stomach?

Answer 3

Pepsin is a proteolytic enzyme (breaks down protein) when activated by HCl

Question 4

The walls of the parietal cells contain what 3 receptors? When any of these 3 receptors is occupied by its corresponding chemical stimulant, what is the result?

Answer 4

1) The walls of the parietal cells contain Ach, histamine and gastrin receptors.
2) When any of these 3 receptors are occupied, the parietal cells produce and secrete H+ ions

Question 5

Define Antacids. What are they usually made up of?

Answer 5

1) Antacids are basic compounds used to neutralize stomach acid
2) Most commonly, they are non-prescription salts of aluminum, magnesium, calcium, and/or sodium.

Question 6

Give an example of a drug that blocks the binding of the hormone gastrin to its receptor on the parietal cell.

Answer 6

There is currently no drug to block the binding of gastrin to to its corresponding receptor on the parietal cell.

Question 7

How do each of the following 3 secretions help to neutralize the effects of stomach acid:

1) Mucous
2) Prostoglandins
3) Bicarbonate

Answer 7

1) Mucous - Serves as a protective barrier against HCl
2) Prostoglandins - Prevents histamine from binding to its corresponding receptor on the parietal cell
3) Bicarbonate - Acts acts as a buffer by binding with H+ ions

Question 8

Name 2 contraindications to the use of Antacids

Answer 8

1) Severe Renal Failure - Because of the potential toxic accumulation of electrolytes in the antacids
2) GI Obstruction - Because Antacids may stimulate GI motility when it it is undesirable

Question 9

What are the adverse effects of each of the following type of Antacid?

1) Magnesium (i.e., Milk of Magnesia)
2) Aluminum
3) Calcium
4) Sodium Bicarbonate

Answer 9

1) Magnesium - Diarrhea
2) Aluminum - Constipation, hypercalcemia, hypophosphatemia
3) Calcium - Constipation, kidney stones, rebound hyperacidity, milk-alkali syndrome
4) Sodium Bicarbonate - Metabolic alkalosis, electrolyte disturbances

Question 10

What are the 4 MOAs by which Antacids cause interactions?

Answer 10

1) Adsorption - Reduces the ability of other drugs to be absorbed into the body
2) Chelation - Chemical inactivation of other drugs
3) Increased stomach pH - Increases the absorption of basic drugs and decreases the absorption of acidic drugs
4) Increased Urinary pH - Increases the excretion of acidic drugs and decreases the excretion of basic drugs

Question 11

Which two categories of antacids are often recommended for patients with renal compromise because they are more easily excreted than Antacids in other categories?

Answer 11

1) Aluminum-Based Antacids

2) Sodium-Based Antacids

Question 12

What are the MOAs and drug effects of H2 Receptor Antagonists (H2RAs)?

Answer 12

H2RAs competitively block the H2 receptor of the acid-producing parietal cell, which also makes the parietal cell less responsive to Ach and Gastrin. This causes a reduction in H+ ion production by the parietal cell.

Question 13

What are 6 Indications of H2RAs?

Answer 13

1) GERD
2) Peptic Ulcer Disease
3) Erosive Esophogitis
4) Upper GI Bleeding
5) Gastric Hypersecretory Conditions (i.e., Zollinger-Ellison Syndrome)
5) Stress Ulcer Prophylaxis

Question 14

What are 2 relative contraindications that may warrant dosage adjustments of H2RAs?

Answer 14

1) Liver dysfunction

2) Kidney dysfunction

Question 15

What are the adverse effects of H2RAs

Answer 15

1) Confusion and disorientation
2) Increased prolactin secretion
3) Gynecomastia (with cimetidine)
4) Hypotension (with IV) pg 794
5) Thrombocytopenia

Question 16

(T/F) Smoking decreases the effectiveness of H2RAs

Answer 16

True

Question 17

What is the MOA and drug effect of Proton Pump Inhibitors (PPI)?

Answer 17

PPIs bind irreversibly to the hydrogen-potassium ATPase pump and inhibits the movement of H+ ions out of the parietal cell and into the stomach.

Question 18

What are the 6 Indications of PPIs?

Answer 18

1) Erosive esophagitis
2) GERD (when poorly responsive to H2RAs)
3) Short-term treatment of active duodenal ulcers and active benign-gastric ulcers
4) Gastric hypersecretory conditions
5) NSAID-induced ulcers
6) Stress ulcer prophylaxis

Question 19

What the two concerns prescribers have when prescribing PPIs?

Answer 19

1) GI Tract Infections - Because of reduced acid-mediated antimicrobial protection.
2) Osteoperosis - Inhibition of stomach acid is thought to speed up bone mineral loss.

Question 20

(T/F) PPIs should be taken on an empty stomach because food decreases their absorption.

Answer 20

True

Question 21

Which Acid-Controlling drug requires that level of consciousness (especially in the elderly) be assessed before administration?

Answer 21

H2RAs

Question 22

Which Acid-Controlling drug requires that swallowing capacity be assessed because of the size of some of the oral capsules?

Answer 22

PPIs

Question 23

Why might an Aluminum-containing antacid be prescribed in conjunction with a Magnesium-containing antacid?

Answer 23

To cancel out the adverse effects of each other. Magnesium = diarrhea and Aluminum = constipation.

Question 24

What are the specific indications of the 4 types of Antidiarrheal class of drugs?

Answer 24

1) Adsorbents - Mild diarrhea
2) Anticholinergics - Severe diarrhea
3) Opiates - Severe diarrhea
4) Intestinal Flora Modifiers - Antibiotic induced diarrhea

Question 25

What are the mechanisms of action of sucralfate?

Answer 25

1) Sucralfate binds to he exposed proteins of ulcers and erosions, forming a protective barrier that can be thought of as a liquid bandage against HCl and pepsin.
2) Sucralfate also binds and concentrate epidermal growth factor, present in the gastric tissues, which promotes ulcer healing.
3) Stimulates secretion of prostoglandins

Question 26

What are the adverse effects of Sucralfate?

Answer 26

1) Nausea
2) Constipation
3) Dry mouth

Question 27

What are the indictions of Sucralfate?

Answer 27

1) Stress ulcers
2) Esophogeal erosions
3) Peptic ulcer disease

Question 28

Despite its many beneficial actions, why has sucralfate fallen out of common use?

Answer 28

Its effects are transient and multiple daily dosing (up to 4 times daily) is required.

Question 29

What is the mechanism of action of misoprotol?

Answer 29

It is a synthetic prostoglandin analogue and therefore inhibits gastric acid secretion by blocking H2 receptors on parietal cells.

Question 30

What are the indications of misoprostol?

Answer 30

1) Reduces the incidence of gastric ulcers in PTs taking NSAIDs

Question 31

What are the adverse effects of Misoprostol?

Answer 31

1) Headache
2) GI distress (abdominal cramps & diarrhea)
3) Vaginal bleeding

Question 32

Why are Misoprostols not believed to be as effective as H2RAs and PPIs for duodenal ulcers?

Answer 32

Because the Misoprostols must be used in dosages that usually produce disturbing adverse effects such as abdominal cramps, and diarrhea.

Question 33

What is the indication of Simethicone?

Answer 33

Relief of painful symptoms from excess gas in the GI tract that may occur because of air swallowing, dyspepsia, peptic ulcer, or diverticultis.

Question 34

What is the mechanism of action of Simethicone?

Answer 34

It causes mucous coated gas bubbles to break up into smaller ones.