Peptic ulcers Flashcards
What is the mechanisms of action of antacids?
SODIUM BICARBONATE
- NaHCO3
- Lasts 1-2 hours
- Reacts FAST
- Common adverse effects = reduced drug bioavailability and enteric infection
- Sepecific Adverse effects = metabolic alkalosis, excessive NaCl absorption, GAS/BLOATING
Calcium carbonate
- CaCO3
- duration of action = 1-2hrs
- Reacts moderately fast
- Common adverse effects = reduced drug bioavailability, enteric infection
- Specific adverse effects = ACID REBOUND, GAS/BLOATING
Magnesium hydroxide
- Mg(OH)2
- Duration of action = 1-2 hrs
- Reacts slows
- common adverse effects = Reduced drug bioavailability, enteric infection
- SPECIFIC ADVERSE EFFECTS = OSMOTIC DIARRHEA
Aluminum hydroxide
- Al(OH)2
- Duration of action = 1-2hrs
- Reacts slowly
- Common adverse effects = reduced drug bioavailability, eneteric infection
- SPECIFIC ADVERSE EFFECTS = constipation, ALUMINUM TOXICIITY (impaired renal function)
Describe the uses of antacids
- GERD
- peptic ulcers
- dyspepsia
- Just as efficacious to H2-receptor antagonists
describe H2-receptor antagonists
- Competitive inhibitors of histamine H2-receptors in the stomach
–> partially block gastrin and acetylcholine induced acid secretion
- just as efficacious as antacids, but MUCH LONGER DURATION OF ACTION
Cimetidine
- Duration of action = 10 hrs (6hrs OTC)
- common adverse effects (very safe drugs): headache*, diarrhea, fatigue, constipation, infection etc
- ADVERSE EFFECTS:
–> CNS EFFECTS (confusion, hallucinations, agitation)
–> Endocrine effects
ranitidine, nizatidine, famotidine
- Duration of action = 10 hrs (6hrs OTC)
- Common adverse efects = headache, diarrhea, fatigue, constipation, infection
- USES: dyspepsia, gastritis, GERD, peptic ulcers
describe the mechanisms of action of the Proton pump inhibitors (PPI’s)
- Mechanisms of action: block H/K-ATPase (final common pathway)
–> require a LOW pH to be activated
–> become concentrated at parietal cells and concentrated on the luminal side of the cell
–> PPIs IRREVERSIBLY BIND to an INHBIT H/K-ATPase
- Reactivation of the H/K-ATPase requires new protien synthesis of the pump
Omeprazole, lansoprazole, rabeprazole, esomeprazole, pantoprazole
- Prazole = PPI
- Duration of action = 24 hours (takes 3-4 days of dosing to reach max effect)
- Common adverse effects (extremely safe): Decreased drug bioavailability, Diarrhea, headache, abdominal pain
- ADVERSE EFFECTS: decreased nutrient absorption (B12, iron, calcium, zinc), enteric and respiratory infection
describe the therapeutic uses for omeprazole, lansoprazole, rabeprazole, esomeprazole, pantoprazole
- GERD
- Peptic ulcers
- dyspepsia, gastritis, hypersecretory diseases
- NSAID-associated ulcer
- H. Pylori-assocaited ulcer
**Most efficacious inhibitors of acid secretion**
describe mechanism of action of mucosal protective agents
- creates a physical barrier to protect ulcerated tissue and promote healing or stimulates the secretion of the gastric protective factors (MUCUS AND HCO3-)
–> sucralfate and bismuth subsalicyclate for protective barrier over damaged tissue to prevent further tissue damage by H+ or pepsin
–> also stimulate mucus and HCO3- production
–> Misoprostol (prostaglandin derivative) does not form a physical barrier to protect the gastric mucosa
SUCRALFATE
- Duration of action = 6hrs
- common adverse effects = constipation, impaired drug absorption
- USE CAUTION WITH RENAL INSUFFICIENT PATIENTS
- MECH of ACTION
–> forms protective barrier + stimulate mucus and HCO3- production
- Used if you don’t want to impact acid secretion
MISOPROSTOL
- duration of action = 6 hours
- Common adverse effects = cramping diarrhea
- CAN CAUSE ABORTIFICIENT (causes smooth muscle contraction)
- mech of action
–> prostaglandin derivative (stimulates mucus and bicarbonate secretion, suppression of HCl secretion, increase gastric blood flow)
- USE = NSAID-associated ulcers
