Gastro-Intestinal Pharmacology Overview

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Questions and Answers

What is the classic symptom of gastroesophageal reflux disease (GERD)?

Severe stomach pain

Nausea and vomiting

Frequent and persistent heartburn (correct)

Weight loss

Which of the following factors can directly irritate the gastric mucosa?

Chocolate (correct)

Lean meats

Whole grains

Fiber-rich foods

What must occur for gastroesophageal reflux to become classified as GERD?

All three lines of defense must be impaired (correct)

Presence of hiatal hernia

Weight gain in the patient

Increase in stomach acidity

What is the role of the lower esophageal sphincter (LES) during swallowing?

It relaxes to allow the passage of food into the stomach Signup and view all the answers

What is one of the primary goals of therapy for esophageal reflux?

Alleviate or eliminate symptoms Signup and view all the answers

Which phase of treatment involves lifestyle changes and OTC medications for heartburn?

Phase I Signup and view all the answers

Which of the following is a factor that decreases esophageal mucosal resistance?

Decreased bicarbonate movement from blood to mucosa Signup and view all the answers

Which of the following can stimulate acid secretions in the stomach?

Soda Signup and view all the answers

What pharmacological intervention is preferred for rapid symptom relief and healing in moderate to severe GERD?

Proton pump inhibitors (PPIs) Signup and view all the answers

What does the clearance of refluxed materials from the esophagus rely on?

Gravitational effects and peristalsis Signup and view all the answers

Which of the following lifestyle modifications can help manage esophageal reflux symptoms?

Elevating the head of the bed 6-8 inches Signup and view all the answers

What is a common symptom that might indicate the need for treatment of GERD?

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

What type of refluxed material is considered more damaging to the esophagus?

Acidic fluid Signup and view all the answers

Which agent is commonly utilized to enhance gastric emptying in GERD treatment?

Metoclopramide Signup and view all the answers

What constitutes Phase II of GERD treatment?

Pharmacologic intervention with antisecretory therapy Signup and view all the answers

Which of the following is a potential complication of GERD that treatment aims to prevent?

Pulmonary disease Signup and view all the answers

What is the primary action of antacids?

They increase LES pressure. Signup and view all the answers

Which of the following is a common reason for the use of proton pump inhibitors (PPIs)?

To treat moderate to severe GERD. Signup and view all the answers

What is the recommended dosing range for esomeprazole?

20 to 40 mg daily. Signup and view all the answers

When should prokinetic agents like metoclopramide be administered?

At least 30 minutes prior to meals. Signup and view all the answers

What is NOT a result of therapy with prokinetic agents?

Improved gastric acid secretion. Signup and view all the answers

Which of the following products is typically used for antacid therapy?

Calcium carbonate. Signup and view all the answers

Why do nearly half of all pregnant women experience issues related to gastric acid?

Decreased LES pressure and increased abdominal pressure. Signup and view all the answers

Which of the following is an appropriate indication for higher doses of PPIs?

Patients with breakthrough symptoms. Signup and view all the answers

Study Notes

Gastro-Intestinal (GI) Pharmacology

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

GI Picture

A diagram showing the major organs of the digestive system.
Labels for organs like the mouth, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (colon, cecum, rectum), liver, gallbladder, pancreas, and anus.

Gastroesophageal Reflux Disease (GERD)

GERD is characterized by the flow of stomach contents back into the esophagus.
Typical symptoms include frequent and persistent heartburn.
Other symptoms, such as belching, regurgitation, and hypersalivation, may also occur when pH is less than 4.
GERD might have atypical symptoms, like a chronic cough, hoarseness, or chest pain (mimicking angina).
Possible symptoms may only be noticeable with an "omeprazole test".

Normal Physiology Functions - Esophagus

The esophagus transports food from the mouth to the stomach via peristaltic contractions.
The lower esophageal sphincter (LES) relaxes during swallowing, allowing food entry into the stomach, and then contracts to prevent reflux.

Pathogenesis of GERD

For GERD onset, 3 lines of defense must be compromised:
- 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 of GERD

Factors decreasing LES pressure include: chocolate, alcohol, fatty meals, coffee, cola, tea, garlic, onions, and smoking.
Factors directly irritating the gastric mucosa include tomato-based products, coffee, spicy foods, citrus juices, NSAIDs, aspirin, iron, potassium chloride, and alendronate.
Substances that stimulate acid secretions are soda, beer, and smoking.

Lines of Defense

Clearance of refluxed materials from the esophagus, including primary and secondary peristalsis, gravitational effects.
Esophageal mucosal resistance, including mucus production in the esophagus, and bicarbonate movement from the blood to the mucosa.

Factors Determining Extent of Esophageal Damage

Factors influencing esophageal damage include the amount of damage, composition of refluxed material, volume of refluxed material, length of contact time of reflux material, natural sensitivity of esophageal mucosa, and rate of gastric emptying.
A key consideration is whether acid or alkaline refluxed material is worse.

Complications of GERD

Esophagitis
Esophageal strictures and ulcers
Hemorrhage
Perforation
Aspiration
Asthma attack precipitation

Warning Signs Requiring Endoscopy

Dysphagia
Odynophagia
Bleeding
Unexplained weight loss
Choking
Chest pain

Diagnosis of GERD

Clinical symptoms and history
Presenting symptoms and associated risk factors
Empiric therapy and monitoring of improvement
Endoscopy if warning signs are present

When to Refer for Further Care

Chest pain
Heartburn while taking PPIs or persistent heartburn after 2 weeks of treatment
Nocturnal heartburn symptoms
Frequent heartburn for more than 3 months
GI bleeding and other warning signs
Concurrent use of NSAIDs
Pregnancy or nursing
Children under 12 years old

Therapy Goals

Alleviate or eliminate symptoms
Diminish reflux frequency and duration
Promote healing if the mucosa is damaged
Prevent complications

Therapy

Therapy targets increasing LES pressure, enhancing esophageal acid clearance, improving gastric emptying, protecting esophageal mucosa, decreasing reflux acidity, and decreasing gastric volume available for reflux.

Treatment Phases

Phase I: Lifestyle changes (2 weeks) for mild intermittent heartburn, plus antacids.
Phase II: Pharmacologic intervention (standard/high-dose antisecretory therapy) for symptomatic relief of mild to moderate GERD, involving lifestyle changes plus standard doses of proton pump inhibitors (PPIs) for 4–8 weeks.
Phase III: Surgical intervention for patients who fail pharmacologic treatment or have severe GERD complications, possibly involving repositioning the LES within the abdomen.

Treatment Selection

Mild intermittent heartburn: Lifestyle changes and antacids.
Mild to moderate GERD (Phase II): Lifestyle changes plus standard doses of PPIs (4–8 weeks).
Moderate to severe GERD (Phase II): Lifestyle changes plus PPIs (8–16 weeks), possibly with prokinetic agents.

Examples of Prokinetic Agents

Metoclopramide
Domperidone

Lifestyle Modifications

Elevate the head of the bed (6–8 inches)
Decrease fat intake
Stop smoking
Avoid recumbency for 3 hours after meals
Lose weight
Limit alcohol intake
Wear loose-fitting clothing
Avoid aggravating foods

Drug Therapy - Antacids

Antacids increase LES pressure but do not promote esophageal healing.
They neutralize gastric acid, causing alkalinization.
Alginic acid forms a viscous solution that floats on top of stomach contents.
Use as needed with typical action of 1-3 hours.
Antacid products include magnesium salts, aluminum salts, calcium carbonate, and sodium bicarbonate. Some brand examples include Maalox/Mylanta, Maalox TC/Mylanta II, Gaviscon, Tums (Calcium Chloride) and Nugel.

Drug Therapy - PPIs

Used to treat moderate to severe GERD, choosing based on cost.
Omeprazole was made OTC in 2003.
Used for heartburn occurring 2+ times per week.
Standard doses include: esomeprazole (20-40 mg daily), lansoprazole (15-30 mg daily), omeprazole (20-40 mg daily), pantoprazole (40 mg daily), and rabeprazole (20 mg daily).
Timing is best 30 to 60 minutes before a meal.
Higher doses may be needed in some patients.

Drug Therapy - Prokinetics

Enhances smooth muscle motility from the esophagus to the proximal small bowel.
Accelerates gastric emptying and transit of intestinal contents from the duodenum.
Results in improved gastric emptying, enhanced tone of the lower esophageal sphincter, and stimulated esophageal peristalsis.
Prokinetic agent example: Metoclopramide (10-15 mg before meals and at bedtime).

Special Populations - Pregnancy

GERD is common due to decreased LES pressure and increased abdominal pressure.
Nearly half of all pregnant women experience GERD.
Antacids are generally safe but avoid chronic high doses.

Counseling Questions

Duration and frequency of symptoms
Quality and timing of symptoms
Alcohol and tobacco use
Dietary choices
Medications already tried
Other underlying conditions and medications used

Case Study

A 45 year old male postal worker with heartburn 3-4 times per month, appearing after meals.
Has tried Tums with partial success.
Questions to ask AA: history, details of the pain, lifestyle, medications, and medical history.
Reasons for referral: severe symptoms or potential complications.
Probable GERD type: mild.
Recommended treatment: lifestyle modifications and PPIs.

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Description

This quiz explores the pharmacology of the gastrointestinal (GI) system, focusing on the actions of drugs that affect GI function. You'll learn about important conditions like GERD and the anatomy of the digestive tract, including its major organs. Test your knowledge of how medications can normalize impaired GI functions and understand chronic diseases associated with the GI system.