GI Pharmacology and Disorders

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Questions and Answers

What is the primary function of the lower esophageal sphincter (LES)?

Prevents food from entering the stomach

Relaxes to allow air to escape from the stomach

Facilitates the absorption of nutrients

Contracts to prevent reflux after swallowing (correct)

Which of the following factors can decrease the pressure of the lower esophageal sphincter (LES)?

Protein-rich meals

High fiber foods

Citrus juices (correct)

Whole grains

What is a significant symptom of gastroesophageal reflux disease (GERD)?

Frequent and persistent heartburn (correct)

Nausea after eating

Severe abdominal cramps

Unexplained weight loss

What contributes to the impaired defense mechanisms in the esophagus leading to GERD?

Decreased clearance of refluxed materials Signup and view all the answers

Which material is worse for causing esophageal damage: acid or alkaline reflux?

Acid reflux Signup and view all the answers

What does the GI tract include?

The mouth to the anus including all intermediate structures Signup and view all the answers

Which of the following beverages is known to stimulate acid secretion?

Soda Signup and view all the answers

Which component in the esophagus contributes to mucosal resistance?

Mucus production Signup and view all the answers

Which of the following can irritate the gastric mucosa directly?

Potassium Chloride Signup and view all the answers

What physiological mechanism helps clear refluxed materials from the esophagus?

Primary and secondary peristalsis Signup and view all the answers

What is one of the main therapy goals for treating esophageal reflux?

Promote healing if the mucosa is injured Signup and view all the answers

In Phase I of the treatment for mild intermittent heartburn, what is primarily recommended?

Lifestyle changes plus antacids Signup and view all the answers

What is the action of antacids with alginic acid in gastric treatment?

Forms a viscous solution that floats on gastric contents Signup and view all the answers

What is a lifestyle modification recommended to alleviate symptoms of GERD?

Avoid recumbency for at least 3 hours post-prandial Signup and view all the answers

Which of the following is a characteristic of Phase II in the treatment of GERD?

Standard/high-dose antisecretory therapy Signup and view all the answers

Which of the following is NOT a type of proton pump inhibitor?

Metoclopramide Signup and view all the answers

Which of the following is NOT a goal of GERD therapy?

Increase acid production in the stomach Signup and view all the answers

When should the second dose of a PPI be taken for optimal effectiveness?

30 to 60 minutes before the evening meal Signup and view all the answers

What treatment is preferred for healing erosive esophagitis in moderate to severe GERD?

Proton pump inhibitors (PPI's) for 8-16 weeks Signup and view all the answers

What is a primary use of prokinetic agents?

To enhance esophageal motility Signup and view all the answers

Which of the following statements about magnesium salts as antacids is correct?

They help neutralize gastric acid. Signup and view all the answers

Which of the following reflects a typical symptom of GERD?

GI bleeding and other warning signs Signup and view all the answers

Which prokinetic agent is mentioned as part of the treatment options?

Metoclopramide Signup and view all the answers

What is the recommended dose of Esomeprazole for treating GERD?

20 to 40 mg daily Signup and view all the answers

What is a consequence of untreated esophageal reflux?

Complications such as esophagitis Signup and view all the answers

How are prokinetic agents typically administered?

At least 30 minutes before meals Signup and view all the answers

What dietary change is suggested to help manage GERD symptoms?

Limit alcohol intake Signup and view all the answers

Which population commonly experiences the need for antacids due to physiological changes?

Pregnant women Signup and view all the answers

What should be monitored when prescribing Metoclopramide?

Documented motility dysfunction Signup and view all the answers

Which of the following is true regarding the mechanism of action for antacids?

They neutralize gastric acid. Signup and view all the answers

Study Notes

Gastro-Intestinal (GI) Pharmacology

GI Pharmacology encompasses the actions of drugs affecting GI system function.
These drugs normalize impaired function in the GI tract.
The GI tract is the passageway of the digestive system, leading from the mouth to the anus (oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, and anal canal).

GI Picture

Diagram showing the major components of the GI tract: mouth, esophagus, stomach, duodenum, jejunum, ileum, colon/large intestine, rectum, anus, liver, gallbladder, pancreas, ileocecal valve.

Gastroesophageal Reflux Disease (GERD)

GERD is characterized by the reflux of gastric contents into the esophagus.
Reflux: The flow back or return; abnormal reflux of gastric contents into the esophagus can cause symptoms or mucosal damage.
Typical symptom is frequent and persistent heartburn.

Normal Physiology Functions (Esophagus and LES)

Esophagus: Transports food from the mouth to the stomach via peristaltic contractions.
Lower Esophageal Sphincter (LES): Relaxes during swallowing to allow food to enter the stomach and then contracts to prevent reflux.

Pathogenesis of GERD

3 lines of defense must be impaired for GERD to develop.
LES barrier impairment
Relaxation of LES, low resting LES pressure.
Increased gastric pressure
Decreased clearance of refluxed materials from the esophagus.
Decreased esophageal mucosal resistance.

Contributing Factors

Decreased LES pressure: Chocolate, alcohol, fatty meals, coffee, cola, tea, garlic, onions, smoking.
Direct irritation of the gastric mucosa: Tomato-based products, coffee, spicy foods, citrus juices, NSAIDs, aspirin, iron, potassium chloride, alendronate.
Stimulate acid secretions: Soda, beer, smoking.

Lines of Defense

Clearance of refluxed materials from the esophagus.
Primary peristalsis from swallowing – increases salivary flow.
Secondary peristalsis from esophageal distension.
Gravitational effects.
Esophageal mucosal resistance: Mucus production in the esophagus and bicarbonate movement from blood to mucosa.

Factors Determining Extent of Esophageal Damage

Amount of esophageal damage is dependent on:
Composition of refluxed material (acid or alkaline).
Volume of refluxed material.
Length of contact time of reflux material.
Natural sensitivity of esophageal mucosa
Rate of gastric emptying.

Typical Symptoms

Common symptoms experienced when pH < 4: Heartburn, belching, regurgitation, hypersalivation.
Symptoms may be aggravated by meals and reclining position.

Atypical Symptoms

Chronic cough, hoarseness, and chest pain (mimics angina)
Possible only symptoms – “omeprazole test.”

Complications

Esophagitis, esophageal strictures and ulcers, hemorrhage, perforation, aspiration, precipitation of an asthma attack.

Warning Signs

Requires endoscopy if present: Dysphagia, odynophagia, bleeding, unexplained weight loss, choking, and chest pain.

Diagnosis

Clinical symptoms and history; Presenting symptoms and associated risk factors, Give empiric therapy and look for improvement.
Endoscopy if warning signs are present.

When to Refer for Further Care

Chest pain, heartburn while taking PPIs, or heartburn that continues after 2 weeks of treatment.
Nocturnal heartburn symptoms, frequent heartburn for >3 months, GI bleeding and other warning signs, concurrent use of NSAIDs.
Pregnant or nursing patients, children <12 years old.

Therapy Goals

Alleviate or eliminate symptoms.
Diminish frequency and duration of esophageal reflux.
Promote healing if the mucosa is injured.
Prevent complications.

Therapy

Directed at: Increasing LES pressure, enhancing esophageal acid clearance, improving gastric emptying, protecting esophageal mucosa, decreasing acidity of reflux, decreasing gastric volume available to be refluxed.

Treatment

Three phases:
Phase I: Lifestyle changes (2 weeks), lifestyle modifications, patient-directed therapy with OTC medications.
Phase II: Pharmacologic intervention (standard/high-dose antisecretory therapy).
Phase III: Surgical intervention.
Severe GERD complications, patients who fail pharmacologic treatment.
LES positioned within the abdomen where it's under positive pressure.

Treatment Selection

Mild intermittent heartburn (Phase I): Lifestyle changes plus antacids.
Symptomatic relief of mild to moderate GERD (Phase II): Lifestyle changes plus standard doses of proton pump inhibitors (PPIs) for 4-8 weeks.
Healing of erosive esophagitis or treatment of moderate to severe GERD (Phase II): Lifestyle modifications plus PPIs for 8-16 weeks.
- PPIs are the preferred initial choice due to more rapid symptom relief and higher rate of healing.
May also add a prokinetic agent in selected patients.

Examples of Prokinetic Agents

Metoclopramide, Domperidone.

Lifestyle Modifications

Elevate the head of the bed 6-8 inches, decrease fat intake, smoking cessation, avoid recumbency for at least 3 hours post-prandial, weight loss, limit alcohol intake, wear loose-fitting clothing, avoid aggravating foods.

Drug Therapy - Antacids

Antacids with or without alginic acid: Increase LES pressure and do not promote esophageal healing.
Neutralize gastric acid, causing alkalinization.
Alginic acid forms a highly viscous solution that floats on top of gastric contents.
Dose as needed; typical action is 1-3 hours.
Products: Magnesium salts, aluminum salts, calcium carbonate, sodium bicarbonate.
Examples: Maalox/Mylanta, Maalox TC/Mylanta II, Gaviscon, Tums, Nugel tabs or suspension.

Drug Therapy - PPIs

Proton Pump Inhibitors (PPIs) treat moderate to severe GERD.
All agents are effective.
Omeprazole released OTC.
Use for heartburn that occurs ≥2 days/week.
Standard dosing: Esomeprazole 20-40 mg daily (approved for adolescents 12-17 years), Lansoprazole 15-30 mg daily, Omeprazole 20-40 mg daily, Pantoprazole 40 mg daily, and Rabeprazole 20 mg daily.
Timing: Best taken 30-60 minutes prior to meals.
May give higher doses BID for patients with a partial response.
Patients with breakthrough symptoms; patients with severe esophageal dysmotility.
Always give a second dose 30-60 min prior to evening meal.

Drug Therapy - Prokinetics

Prokinetic agents enhance motility of smooth muscle, accelerating gastric emptying.
Results of therapy: Improved gastric emptying, enhanced tone of the lower esophageal sphincter, stimulated esophageal peristalsis.
Prokinetic Agents - Products: Metoclopramide (only use if motility dysfunction is documented, administer at least 30 minutes prior to meals, dose 10-15 mg before meals and at bedtime).

Special Populations

Pregnancy: Common due to decreased LES pressure and increased abdominal pressure.
Nearly half of all pregnant women experience GERD.
Antacids generally considered safe, but avoid chronic high doses.

Counseling Questions

Before recommending a therapy, ask about the duration and frequency of symptoms, quality and timing of symptoms, use of alcohol and tobacco, dietary choices, medications already tried to treat symptoms, and other disease states present and medications being used.

Case Study

AA, a 45-year-old male postal worker, complains of heartburn 3-4 times per month, typically after meals.
- Has tried Tums with some success and wants something more effective.
Questions to ask: What questions should you ask AA first? What would cause you to refer AA to a physician? What type of GERD does AA have? What treatment should you recommend?

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Description

Explore the essentials of Gastro-Intestinal Pharmacology, focused on drugs that impact GI system function, including their role in treating conditions like GERD. This quiz also covers the anatomy of the GI tract and the normal physiology of the esophagus and lower esophageal sphincter (LES).