Pharmacology of Antacids

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Questions and Answers

What is the primary mechanism of action of proton pump inhibitors (PPIs)?

Neutralize stomach acid by increasing pH.

Bind to H2 receptors on gastric parietal cells.

Inhibit the H+/K+ ATPase enzyme in gastric parietal cells. (correct)

Protect the gastric mucosa from injury.

Which of the following is NOT an indication for proton pump inhibitors (PPIs)?

Hypertension. (correct)

Gastroesophageal reflux disease (GERD).

NSAID-induced ulcers.

Peptic ulcer disease.

What is a common adverse effect of magnesium-containing antacids?

Diarrhea. (correct)

Constipation.

Dizziness.

Headache.

Which type of medication is used to protect the gastric mucosa from injury?

Gastroprotective agents. Signup and view all the answers

What is the goal of anti-secretory therapy in the treatment of peptic ulcers?

Reduce acid secretion to promote healing. Signup and view all the answers

Which of the following is an example of a combination therapy for Helicobacter pylori eradication?

PPIs or H2 blockers + antibiotics. Signup and view all the answers

What is a common adverse effect of cimetidine, an H2 blocker?

Impotence. Signup and view all the answers

Which type of medication is used to neutralize stomach acid?

Antacids. Signup and view all the answers

What is a characteristic of antacids in heartburn relief?

They neutralize stomach acid to provide fast relief Signup and view all the answers

What is the primary benefit of H2 blockers over antacids?

Longer-lasting relief Signup and view all the answers

What is a limitation of antacids in treating acid reflux?

They may not be effective in severe acid reflux Signup and view all the answers

What is a common side effect of antacids?

Diarrhea or constipation Signup and view all the answers

What is a characteristic of proton pump inhibitors (PPIs)?

They block the production of stomach acid Signup and view all the answers

What is a potential advantage of H2 blockers over PPIs?

Fewer side effects Signup and view all the answers

What is a rare but serious side effect of antacids?

Kidney stones Signup and view all the answers

What is a lifestyle change that can help alleviate acid reflux symptoms?

Avoiding trigger foods Signup and view all the answers

Study Notes

Proton Pump Inhibitors (PPIs)

Mechanism of action: Inhibit the H+/K+ ATPase enzyme in gastric parietal cells, reducing acid secretion
Examples:
- Omeprazole
- Lansoprazole
- Rabeprazole
- Esomeprazole
- Pantoprazole
Indications:
- Gastroesophageal reflux disease (GERD)
- Peptic ulcer disease
- Zollinger-Ellison syndrome
- NSAID-induced ulcers
Adverse effects:
- Headache
- Diarrhea
- Abdominal pain
- Increased risk of Clostridioides difficile infection

H2 Blockers (Histamine-2 Antagonists)

Mechanism of action: Bind to H2 receptors on gastric parietal cells, reducing acid secretion
Examples:
- Ranitidine
- Famotidine
- Nizatidine
- Cimetidine
Indications:
- Peptic ulcer disease
- GERD
- Zollinger-Ellison syndrome
Adverse effects:
- Headache
- Dizziness
- Constipation
- Impotence (cimetidine)

Antacids

Mechanism of action: Neutralize stomach acid by increasing pH
Examples:
- Sodium bicarbonate
- Magnesium hydroxide (Mylanta)
- Aluminum hydroxide (Amphojel)
- Calcium carbonate (Tums)
Indications:
- Heartburn
- Indigestion
- Upset stomach
Adverse effects:
- Diarrhea (magnesium-containing antacids)
- Constipation (aluminum-containing antacids)
- Interactions with other medications (e.g., tetracycline)

Gastroprotective Agents

Mechanism of action: Protect the gastric mucosa from injury
Examples:
- Sucralfate
- Misoprostol
Indications:
- Prevention of NSAID-induced ulcers
- Treatment of duodenal ulcers
Adverse effects:
- Constipation (sucralfate)
- Diarrhea (misoprostol)

Anti-secretory Therapy

Goal: Reduce acid secretion to promote healing of peptic ulcers and prevent recurrence
Combination therapy:
- PPIs or H2 blockers + antibiotics (e.g., clarithromycin, amoxicillin) for Helicobacter pylori eradication
- PPIs or H2 blockers + gastroprotective agents for NSAID-induced ulcers

Proton Pump Inhibitors (PPIs)

Inhibit H+/K+ ATPase enzyme in gastric parietal cells, reducing acid secretion
Examples: omeprazole, lansoprazole, rabeprazole, esomeprazole, pantoprazole
Used to treat: Gastroesophageal reflux disease (GERD), peptic ulcer disease, Zollinger-Ellison syndrome, NSAID-induced ulcers
Adverse effects: headache, diarrhea, abdominal pain, increased risk of Clostridioides difficile infection

H2 Blockers (Histamine-2 Antagonists)

Bind to H2 receptors on gastric parietal cells, reducing acid secretion
Examples: ranitidine, famotidine, nizatidine, cimetidine
Used to treat: peptic ulcer disease, GERD, Zollinger-Ellison syndrome
Adverse effects: headache, dizziness, constipation, impotence (cimetidine)

Antacids

Neutralize stomach acid by increasing pH
Examples: sodium bicarbonate, magnesium hydroxide (Mylanta), aluminum hydroxide (Amphojel), calcium carbonate (Tums)
Used to treat: heartburn, indigestion, upset stomach
Adverse effects: diarrhea (magnesium-containing antacids), constipation (aluminum-containing antacids), interactions with other medications (e.g., tetracycline)

Gastroprotective Agents

Protect gastric mucosa from injury
Examples: sucralfate, misoprostol
Used to: prevent NSAID-induced ulcers, treat duodenal ulcers
Adverse effects: constipation (sucralfate), diarrhea (misoprostol)

Anti-secretory Therapy

Goal: reduce acid secretion to promote healing of peptic ulcers and prevent recurrence
Combination therapy: PPIs or H2 blockers + antibiotics for Helicobacter pylori eradication, PPIs or H2 blockers + gastroprotective agents for NSAID-induced ulcers

Heartburn Relief

Antacids neutralize stomach acid to relieve heartburn symptoms, providing quick relief within minutes
Antacids can be taken as needed or on a regular schedule to prevent heartburn

Histamine-2 Blockers

Histamine-2 (H2) blockers reduce acid production in the stomach to treat heartburn, acid reflux, and GERD
Examples of H2 blockers include ranitidine (Zantac) and famotidine (Pepcid)
H2 blockers take longer to start working than antacids but provide longer-lasting relief

Acid Reflux Treatment

Antacids may not be effective for severe acid reflux symptoms
Combination therapy with H2 blockers or PPIs may be needed for more severe acid reflux
Lifestyle changes, such as avoiding trigger foods and losing weight, can alleviate acid reflux symptoms

Antacid Side Effects

Common antacid side effects include diarrhea, constipation, bloating, gas, stomach cramps, nausea, and vomiting
Rare but serious side effects include kidney stones, interactions with other medications, high blood pressure, and heart problems

Proton Pump Inhibitors (PPIs)

PPIs block stomach acid production to treat severe acid reflux, GERD, and stomach ulcers
Examples of PPIs include omeprazole (Prilosec) and lansoprazole (Prevacid)
PPIs are more effective than antacids or H2 blockers but may have more side effects and interactions with other medications