GI Drugs p2 Flashcards
Ulcer therapy drugs (5)
- Antacids
- Histamine-2 receptor antagonists
- Mucosal protective drugs
- Prostaglandin analogs
- Proton pump inhibitors
Antacids
1. Systemic or Nonsystemic?
2. Administered… Why?
3. Frequency of use in vet med & why (3)
4. Base types & examples (3)
- Nonsytemic
- Orally to directly neutralize acid
- Little use in vet med because:
- Short-acting, difficult to administer
- Possible electrolyte imbalances
- Rebound increase in acid of Ca+ type - Types
- Ca+ (Tums, Rolaids)
- Magnesium (Mylanta, Maalox)
- Aluminum (Amphojel, Maalox)
Histamine-2 Receptor Antagonists
1. Systemic or Nonsystemic?
2. How it works
3. Examples (3)
- Systemic “antacid”
- Must be absorbed into blood stream to exert effect. - Prevent acid reflux by competitively blocking H2 (histamine) receptors of the parietal cells in the stomach, thus reducing gastric acid secretion.
- Examples
- Cimetidine
- Ranitidine
- Famotidine
Mucosal Protective Drugs
1. How it works
2. Works well for…
3. Example (1)
- Combine with protein to form an adherent substance that covers the ulcer & protects it from stomach acid & pepsin.
- Excellent for esophagus erosions!
- Example
- Sucralfate (Carafate)
T/F: Mucosal protective drugs are thought of as “gastric band-aids”
True!
Prostaglandin analogs
1. What do they do?
2. Example (1)
- Suppress gastric secretions & increase mucus production in the GI tract.
- Misoprostol (Cytotec)
- Typically given to Pt on NSAIDs or high dose steroids for spinal emergencies
T/F: Prostaglandins analogs are the only drugs that can “prevent ulcers” but they are expensive, and diarrhea is a common side effect
True
Proton pump inhibitors bind irreversibly to the ___-___-ATPase enzyme on the surface of parietal cells of the stomach. This inhibits ___ ion transport into the stomach so that it cannot secrete ___ ____.
- Hydrogen (H+)-Potassium (K+)-ATPase
- Hydrogen ion
- Hydrochloric acid (HCl)
What is peristalsis? (3)
- Circular muscle contractions
- Wavelike movements along the GI tract
- Propel digestive tract contents along the tube ahead of them
What are segmental contractions of the GI tract? (3)
- Periodic circular muscle contractions
- Occur in different adjacent sites
- Mixes digestive tract contents & slows their movement thru the tract
Small intestine digestion
1. Walls absorb what? (3)
2. Chemicals absorb what? (3)
3. What does chemical digestion involve? (2)
- Electrolytes, water, & vitamins
- Carbs, proteins, & fats
- Involves:
- Enzymes in the lumen of the intestine
- Enzymes associated with the microvilli
Large intestine
1. Components (2)
2. Primary functions (2)
- Cecum & colon
- Functions
- Recover fluid & electrolytes
- Store feces until they can be eliminated
What is diarrhea?
Caused when the balance between fluid secretion & fluid reabsorption by the intestines is disturbed
Mechanisms (causes) of diarrhea (6)
- Secretory (enterotoxin, IBD)
- Malabsorption (parvo)
- Exudative
- Osmotic
- Increased peristalsis
- Combo of the above mechanisms
What are antidiarrheals? Examples? (5)
- Drugs that either promote reabsorption or decrease secretion into intestinal lumen.
- Ex
- Anticholinergics
- Protectants/adsorbents
- Opiate-related agents
- Probiotics
- Metronidazole
Antidiarrheals Protectants/Adsorbents drugs work by coating ___ intestinal mucosa with a ____ layer (protectants) or bind bacteria &/or digestive enzymes &/or ___ to protect intestinal mucosa from damaging effects (absorbents).
Side effect is ___.
Examples (3)
- Inflamed
- Protective
- Toxins
- Constipation
Examples
- Bismuth
- Kaolin/pectin
- Activated charcoal
T/F: Bismuth turns feces black and is safe to use in cats & dogs
False!
While it does turn feces black, it is contraindicated in cats
Anticholinergic (antidiarrheal)
1. Used to Tx what?
2. Side effects (4)
3. Examples (5)
- Tx tenesmus & vomiting
- Dry MM, Urine retention, Tachycardia, & Constipation.
- Ex
- Atropine
- Aminopentamide (centrine)
- Isopropamide
- Methoscopolamine
Opiate-related agents (antidiarrheals)
1. Work how?
2. Side effects (5)
3. Examples (3)
- Control diarrhea by decreasing both intestinal secretions and the flow of feces & increasing segmental contractions.
- Effects
- CNS depression
- Ileus
- Urine retention
- Bloat
- Constipation (<3-day use) - Examples
- Diphenoxylate
- Loperamide
- Paregoric
A theory regarding the development of diarrhea is that ___ bacteria may increase due to disruption of normal GI ___.
One way to treat this is to use an ___ effective against anaerobic bacteria (esp in colon).
___ & ___ are antibiotics used to treat diarrhea, also have anti-inflammatory properties.
- Anaerobic
- Flora
- Antibiotic
- Metronidazole & Sulfasalazine
Probiotics & Prebiotics theory is that these feed a patient’s bacteria ___. Then beneficial bacteria can ideally ___ __ non-beneficial bacteria.
- Flora
- Crowd out
- Prebiotic
- Probiotic
- Non-digestible food that feeds beneficial GI microbes.
- Must be given in a form that makes it to distal GI & is able to colonize the species treated.
What do laxatives do?
Types? (2)
Soften stool to prevent or treat constipation or prevent tenesmus.
1. Emollient
2. Bulk
Emollients (laxatives)
1. What are they?
2. Examples (3)
- Stool softeners; Lubricants
- Reduce stool surface tension & reduce water absorption thru the colon.
- - Facilitate the passage of fecal material, increasing water retention in stool - Examples
- Docusate sodium succinate (DSS)
- Petroleum products
- Mineral oil
Bulk-forming (laxatives)
1. What is it?
2. Side effects?
3. Soluble fibers (3)
- Substances that absorb water into the intestine, increase fecal bulk, & stimulate peristalsis. This results in large, soft stool production.
- Are not systemically absorbed, so side effects are rare!
- Soluble fibers
- Psyllium hydrophilic mucilloid
- Polycarbophil
- Bran
Cathartics
What are they?
Types (2)
Aggressive emptying of intestinal tract, usually to prevent toxin absorption.
1. Osmotic
2. Irritant
Osmotics (cathartics)
1. How do they work?
2. What are they?
3. Examples (3)
- Pull water into the colon & increase water content in the feces, thereby increasing bulk & stimulating peristalsis.
- Salts or saline product that may cause electrolyte imbalances if absorbed systemically.
- Examples
- Lactulose
- Sodium phosphate (no no in cats)
- Magnesium sulfate
Stimulant (cathartics)
1. How do they work?
2. Examples (3)
- Increase peristalsis by chemically irritating sensory nerve endings in the intestinal mucosa.
- Examples
- Bisacodyl
- Phenolphthalein
- Castor oil
T/F: Stimulant cathartics are absorbed systemically & cause a variety of side effects
True
