Gastrointestinal Flashcards
Examples of Antacids
Magnesium oxide, magnesium hydroxide, aluminum oxide and calcium carbonate
MOA of antacids
buffers neutralize gastric acids and decrease pH-dependent conversion of pepsinogen to pepsin (increasing gastric pH to above 3.5 reduces proteolysis catalyzed by pepsin); reduces gastric damage to mucosal lining
Therapeutic effects of antacids
Reduces gastritis and peptic ulcer disease
Examples of antimicrobials and antibiotics
amoxicillin and/or tetracycline
MOA of bismuth
bismuth increases mucus secretion and disrupts bacterial cell wall adhesion to gastric mucosa, reduces bacterial damage
MOA of antibiotics in gastric pharmacology
antibiotics inhibit bacterial cell growth and eliminate infection by H. Pylori
Therapeutic effect of antimicrobials and antibiotics
to treat peptic ulcer disease, gastritis and H. Pylori
Examples of histamine receptor antagonists
cimetidine and rantidine
MOA of histamine receptor antagonists
parietal cell H2 histamine receptor antagonist; blocks activation of proton pump
therapeutic effect of histamine receptor antagonists
treatment of peptic ulcer disease, gastritis and GERD
examples of proton pump inhibitors
omeprazole and esomeprazole
MOA of proton pump inhibitors
drugs directly inhibit proton pump on parietal cells; slow onset of action
therapeutic effects of proton pump inhibitors
treatment of GERD, peptic ulcer disease, gastritis, esophagitis and esophageal bleeding
Examples of synthetic prostaglandins
misoprostol
MOA of synthetic prostaglandins
prostaglandin receptor agonist along GI tract; mimics the inhibitory effects of prostaglandins on parietal cells
therapeutic effect of synthetic prostaglandins
treat gastritis, peptic ulcer disease caused by steroid and other drugs (NSAIDs)
Example of anti-diarrheal agents
loperamide
MOA of anti-diarrheal agents
opioid receptor agonist along GI tract; mimics inhibitory effects of endorphins
therapeutic effects of anti-diarrheal
treating diarrhea
examples of prokinetic medications
metoclopramide and erythromycin
MOA of metoclopramide
a D2 receptor antagonist that suppresses the inhibitory effects of dopamine on cholinergic smooth muscle contractions along the GI tract.
MOA of erythromycin
Erythromycin is a motilin receptor agonist that triggers smooth muscle contractions on the GI tract
therapeutic effect of prokinetic medications, specifically metoclopramide
metoclopramide is used in the treatment of delayed gastric emptying due to diabetic gastroparesis and GERD.
therapeutic effect of prokinetic medications, specifically erythromycin
Erythromycin is used before endoscopies for emptying
Example of a human guanylin and uroguanylin agonist
linaclotide
MOA of human guanylin and uroguanylin agonists
guanylin acts as an agonist of the guanylyl cyclase receptor that regulates electrolyte and water transport into the lumen of the intestine. Linacotide is a guanylin/guanylate cyclase-c agonist. Draws more water into the stool by bringing more sodium and bicarb into the lumen. Water follows.
Therapeutic effect of linaclotide
Linaclotide is used in the treatment of Irritable Bowel Syndrome with Constipation and Chronic Idiopathic Constipation
things to consider to educate the patient when taking linaclotide
Linzess should be taken on an empty stomach at least 30 minutes before the first meal of the day. Taking linaclotide (Linzess) immediately after the high fat breakfast results in looser stools and a higher stool frequency compared with taking it in the fasted state.
true or false: patients with cystic fibrosis do NOT have the cystic fibrosis transmembrane conductance regulator (CFTR)
true
What are proton pumps?
Proton pumps are found in parietal cells. When stimulated by histamine 2 proton pumps will pump H+ into the stomach which will contribute to hydrochloric acid. When prostaglandins are present in a parietal cell, the proton pumps are turned off.
What are gastric endocrine cells?
extrachromaffin-like cells that are located near parietal cells, contain receptors for gastrin and ACh that when activated trigger the release of histamine that then interacts with parietal cells.
what pH does the gastric content need to be, to convert pepsinogen to pepsin?
less than 3.5
what does pepsin break down?
proteins
What neurotransmitter inhibits cholinergic control of peristalsis?
dopamine
What hormone enhances gastric motility?
motilin
Why should a pt not take metoclopramide for prolonged periods of time?
it may cause tardive dyskinesia d/t its persistent dopamine antagonistic effect
MOA of dicyclomine (bentyl)
cholinergic receptor antagonist in the GI system; suppresses peristalsis and spasms
Treatment of inflammatory bowel disease (could also be used for RA)
Infliximab; it is an IV infusion. Antibody to tumor necrosis factor. Immune system suppressant. Must test for latent TB before administering
