Pharm 2 Flashcards
(16 cards)
cephalic phase
body is expecting a meal
sight, taste, smell, thought of food
Gastric phase
once we have ingested food; stomach is distended, amino acids are strong stimulants of gastrin release, negative feedback in place to inhibit gastrin release
Intestinal phase
gastric motility moves food to small intestine where most of proteins from meal will be absorbed
Factors that protect gastric mucosa from damage
mucus
bicarbonate secretion (neutralizes acid)
blood flow carries acid away from cells and carries bicarb and other protective nutrients to mucosa
prostaglandins stimulate all of this
Factors that damage gastric mucosa
acid secretion pepsin NSAIDs H pylori Smoking Alcohol Ischemia Bile acids
Two most common causes of PUD
h pylori
NSAIDs
Pathogenesis of H pylori
inhibit release of somatostatin (D cells)
impairs secretion of sodium bicarb
produces a significant immune response which results in the release of inflammatory cytokines which contribute to tissue damage and ulceration
damage mucosal defenses by proteases that directly damage mucosal tissues
reduces release of growth factors which normally stimulate replacement mucosal cell growth and development
PPIs
Dexlansoprazole Esomeprazole Lansoprazole Omeprazole Pantoprazole Raberprazole
What should you avoid giving someone who is taking Clopidogrel (plavix)?
Omeprazole and esomeprazole due to CYP2C19 metabolism
also avoid omeprazole in pregnancy
Why are PPIs ideal
short half-lives
concentrated site of action
long duration of action
usually given once daily, but sometimes twice daily (infrequent dosing)
Long-term treatment concerns with PPIs
decreased vitamin B12 absorption
possible interference with calcium absorption
Possible interference with magnesium absorption
Risk of infection
ECL cell hyperplasia and possible development of carcinoid tumors
IBD
H2 histamine receptor antagonists (H2RAs)
Cimetidine (a lot of interactions)
Famotidine (only one to choose from)
Nizatidine (lacks data)
Ranitidine (removed from market due to cancer causing agent)
H2RA mechanism of action
H2RAs bind to and competitively block H2 receptors on the parietal cells –> decreased acid secretion
Antacids
aluminum and magnesium hydroxides
Sodium bicarbonate
Calcium carbonate
Cytoprotective drugs
Sucralfate
Misoprostol
Bismuth Subsalicylate
Antacids MOA
inorganic bases chemically neutralize stomach acid rapidly acting raises pH reduces pepsin
