GI Flashcards
What are the three gastric gland cell types?
- Parietal
- Chief
- Mucoid
What cells are the primary site of action for many acid-controller drugs?
Parietal cells
What do parietal cells secrete?
HCl
What do chief cells secrete?
Pepsinogen
What does pepsin break down?
Proteins
What does mucous protect against?
Self-digestion by HCl
What is the pH of the stomach?
1-4
What are three stimuli for HCl secretion?
- Excessive amounts of alcohol
- Large, fatty meals
- Emotional stress
Acid-related GI disorders are due to an imbalance of what?
The three gastric gland secretions
What is the most common kind of acid-related GI disorder?
Hyperacidity
What are three lay terms for hyperacidity?
- Sour stomach
- Acid stomach
- Heart burn
What is peptic ulcer disease (PUD)?
- Lesion in stomach (gastric)
- Lesion in small intestine (duodenal)
What are six predisposing factors of PUD?
- Heavy ETOH use
- Smoking
- Heavy caffeine use
- Chronic use of ASA (aspirin) and other NSAIDs
- Chronic use of systemic corticosteroids (injection or pill… NOT inhaler)
- Excessive psychological stress
What are two primary etiologies for PUD?
- Chronic NSAID use
- Heliobacter pylori infection
What is a rare condition of hypersecretion of HCl due to gastrinoma?
Zollinger-Ellison Syndrome
In Zollinger-Ellison Syndrome, what does the tumor secrete and what does this cause?
Tumor secretes gastrin
Hypersecretion of HCl
In what age group do duodenal ulcers frequently occur?
30-50
How does a duodenual ulcer manifest?
Hematemesis or melena
In a duodenal ulcer, what can the pain be relieved by?
Eating
Gastric ulcers are more common in what age group?
Over 60
What do gastric ulcers present with?
- Anorexia
- Weight loss
- Vomiting
- Epigastric pain that may/may not be relieved by eating
What are two forms of inflammatory bowel disease (IBD)?
- Crohn’s Disease
- Ulcerative Colitis
Where can inflammation occur in Crohn’s Disease?
Anywhere along the alimentary canal
What is the most common site of inflammation in Crohn’s Disease?
Terminal Ileum
What are the characteristics of the lesions in Crohn’s Disease?
They are “skip lesions”
True or False:
Extraintestinal mainfestations are very common in Crohn’s Disease.
False
(Extraintestinal manifestations less common)
Where does inflammation and ulceration take place in Ulcerative Colitis (UC)?
Large intestine
True or False:
Extraintestinal manifestations are very common in Ulcerative Colitis (UC)
True
In UC, where does pyoderma gangrenosum usually occur?
Cutaneous ulcerations usually in legs
What is erythema nodosum?
Inflammation, scarring, and destruction of bile ducts
What are ten extraintestinal manifestations that occur in IBD (mostly UC)?
- Sacroiliitis
- Osteoporosis
- Peripheral arthritis
- Uveitis
- Scleritis
- Episcleritis
- Nephrolitiasis
- Thromboembolic events
- Pyoderma gangrenosum
- Primary sclerosing cholangitis
What is gastroesophageal reflux disease (GERD)?
HCl from stomach splashes up into esophagus
↓ ↓
Results in severe heartburn and other chest symptoms
What is GERD caused by?
Ineffective lower esophageal sphincter
What are some complications that arise from GERD?
- Esophageal ulcers
- Barrett’s esophagitis
- Esophageal strictures
What happens to the squamous epithelium in the distal esophagus when a person has Barrett’s esophagitis?
Converts to columnar epithelium
(Not normally found here → Pre-malignant)
How do esophageal strictures cause disphagia?
Esophageal lining damaged from HCl
↓ ↓
Develops scar tissue
↓ ↓
Esophageal lining becomes still and scar tissue builds up
↓ ↓
Esophageal narrowing around scar tissue
What are three goals for pharmacotherapy of PUD and GERD?
- Provide relief from symptoms
- Promote healing of ulcer
- Prevent future recurrence of disease
What is the MOA for antacids?
Promote gastric mucosal secretion
Mucus is rich in bicarbonate so it buffers HCl.
True or False:
Antacids prevent the over-production of acid.
False
(Antacids DO NOT prevent the overproduction of acid)
True or False:
Antacids neutralize the acid once it’s present in the stomach.
True
Chronic use of antacids may lead to what?
Rebound hyperacidity
(especially calcium formations)
Raising gastric pH from 1.3 to 1.6 (0.3) neutralizes what percentage of the gastric acid?
What percentage would be neutralized by raising it from 1.3 to 2.3 (1.0)?
50%
90%
What are five OTC formulations of antacids?
- Capsules and tablets
- Powders
- Chewable tablets
- Suspensions
- Effervescent granules and tablets
What are four types of antacids?
- Aluminum salts
- Magnesium salts
- Calcium salts
- Sodium bicarbonate
Why are aluminum salts are often used with magnesium?
Counteract constipation
What is an example of an aluminum?
Aluminum carbonate (Basaljel)
Aluminum causes _________ while magnesium is a __________.
Constipation; laxative
Why do you need to use caution when giving magnesium to a patient with renal failure?
Failing kidney cannot excrete extra Mg
↓ ↓
Magnesium accumulation
What is an example of magnesium?
Magnesium hydroxide (MOM)
What is an example of a combo of magnesium and aluminum?
Maalox and Mylanta
What is the most common form of calcium?
Carbonate
What might calcium cause?
Constipation
Calcium might contribute to the development of what?
Kidney stones
What are two examples of calcium salts?
- Tums
- Rolaids
Sodium bicarb is more commonly known as what?
Baking soda
What are three sodium content cautions?
- CHF
- Htn
- Renal insufficiency
What is a special precaution of sodium bicarb and why?
Alkaseltzer
Because it has sodium bicarb, citric acid, and aspirin
Antiflatulents relieve painful symptoms associated with what?
Gas
Antiflatulents are often added to what combination products?
Antacid
What is the OTC antiflatulent?
Simethicone
What is the MOA of simethicone?
Alters elasticity of mucus-coated bubbles
↓ ↓
Bubbles break
What are five examples of simethicone?
- Phazyme
- Flatulex
- Mylicon
- Gas-X
- Mylanta Gas
Aluminum and calcium cause _________; magnesium causes ________; calcium carbonate causes _______ and __________.
Aluminum and calcium cause CONSTIPATION; magnesium causes DIARRHEA; calcium carbonate causes GAS and BELCHING.
To prevent gas and belching, calcium carbonate is often combined with what?
Simethicone
What is chelation?
Chemical binding with other drugs
↓ ↓
Drugs become inactive
↓ ↓
Insoluble complexes
↓ ↓
Reduced absorption of bioactive drug
What are three drug interactions of antacid?
- Chelation
- Inceased gastric pH
- Increased urine pH
Why does gastric pH rise from taking antacids?
- Increased absorption of basic drugs
- Decrease absorption of acidic drugs
What are five drug interactions of calcium compounds?
- Quinolones
- Tetracycline
- Corticosteroids
- Calcium channel blockers (CCBs)
- Phosphate supplements
Histamine stimulates ________ cells in the stomach to produce ______.
Parietal; HCl
What do H2 antagonists block? What does this cause?
Histamine at the parietal cell H2 receptors
Decreased production of HCl from stomach
True or False:
H2 antagonists are all available OTC.
True
True or False:
H2 anagonists are more popular than PPIs.
False
What are four H2 antagonists?
- Cimetidine (Tagamet)
- Famotidine (Pepcid)
- Nizatidine (Axid)
- Ranitidine (Zantac)
What is the MOA of H2 anatgonists?
Histamine stimulates parietal cells to produce HCl
↓ ↓
H2 antagonists block histamine (H2) at the parietal H2 receptors
↓ ↓
Decreased production of HCl from parietal cells in stomach
What are six indications for H2 antagonists?
- Heal active ulcers
- Maintenance therapy ulcers
- Reduction of GERD symptoms
- Heal erosive esophagitis
- Zollinger-Ellison Syndrome
- Prevent GI bleed in critical care patients (stress ulcers)
True or False:
H2 antagonists are also used in management of severe or refractory allergic conditions.
True
What are H2 antagonists used in conjunction with to manage severe or refractory allergic conditions?
- H1 blockers
- Antihistamines
- Corticosteroids
True or False:
H2 antagonists have a large number of side effects.
False
(Low side effect profile overall - less than 3%)