Acid Controlling Drugs Flashcards
Where are parietal cells located and what do they produce?
Parietal Cells are located in the stomach and they produce HCl
Where are Chief Cells located and what do they produce?
Chief Cells are located in the stomach and they produce pepsingogen (a precursor to pepsin).
What is the role of pepsin in the stomach?
Pepsin is a proteolytic enzyme (breaks down protein) when activated by HCl
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?
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
Define Antacids. What are they usually made up of?
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.
Give an example of a drug that blocks the binding of the hormone gastrin to its receptor on the parietal cell.
There is currently no drug to block the binding of gastrin to to its corresponding receptor on the parietal cell.
How do each of the following 3 secretions help to neutralize the effects of stomach acid:
1) Mucous
2) Prostoglandins
3) Bicarbonate
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
Name 2 contraindications to the use of Antacids
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
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
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
What are the 4 MOAs by which Antacids cause interactions?
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
Which two categories of antacids are often recommended for patients with renal compromise because they are more easily excreted than Antacids in other categories?
1) Aluminum-Based Antacids
2) Sodium-Based Antacids
What are the MOAs and drug effects of H2 Receptor Antagonists (H2RAs)?
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.
What are 6 Indications of H2RAs?
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
What are 2 relative contraindications that may warrant dosage adjustments of H2RAs?
1) Liver dysfunction
2) Kidney dysfunction
What are the adverse effects of H2RAs
1) Confusion and disorientation
2) Increased prolactin secretion
3) Gynecomastia (with cimetidine)
4) Hypotension (with IV) pg 794
5) Thrombocytopenia
(T/F) Smoking decreases the effectiveness of H2RAs
True
What is the MOA and drug effect of Proton Pump Inhibitors (PPI)?
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.
What are the 6 Indications of PPIs?
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
What the two concerns prescribers have when prescribing PPIs?
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.
(T/F) PPIs should be taken on an empty stomach because food decreases their absorption.
True
Which Acid-Controlling drug requires that level of consciousness (especially in the elderly) be assessed before administration?
H2RAs
Which Acid-Controlling drug requires that swallowing capacity be assessed because of the size of some of the oral capsules?
PPIs
Why might an Aluminum-containing antacid be prescribed in conjunction with a Magnesium-containing antacid?
To cancel out the adverse effects of each other. Magnesium = diarrhea and Aluminum = constipation.
What are the specific indications of the 4 types of Antidiarrheal class of drugs?
1) Adsorbents - Mild diarrhea
2) Anticholinergics - Severe diarrhea
3) Opiates - Severe diarrhea
4) Intestinal Flora Modifiers - Antibiotic induced diarrhea
