PUD, GERD, and IBD Flashcards
Tx outline for PUD
- Relief of symptoms
- Healing of ulceration
- Eradicate H. pylori to prevent recurrence
MOA antacids
NaHCO3+HCl=NaCl+CO2+H2O, goal is to raise pH >4
Ingredients in antacids
Aluminum OH–> constipation
Mg OH–> diarrhea
So, logically, a combination of the 2
Dosing and AE of antacids
1 and 3 hr after meal and before bedtime, dont take within 1-2 hrs of other drug, affects other drug absorption
MOA of H2 receptor antagonists
Competitive H2 receptor blockers, inhibit all phases of gastric secretion, reduce volume and H concentration of secretions, minimal side effects
What are the H2 receptor antagonists and how do they differ?
Cimetidine- least potent, inhibits CYP1A2, 2C19, 2D6, 3A4
ranitidine, nizatidine
Famotidine- most potent, take only once a day, reduces theophylline Cx
What are the most potent drugs reducing acid secretion?
PPI
MOA omeprazole
PPI, long duration
MOA lansoprazole
PPI, less effective in severe esophagitis
MOA of PPI
carried by blood to parietal cells and diffuse into secretory canaliculi, trapped by pH protonation due to acidity, bind COVALENTLY to enzyme- noncompetitive–> achlorhydria, new enzymes must be synthesized to overcome
What are the cytoprotective agents?
bismuth subsalicylate, sucralfate
MOA bismuth
enhances secretion of mucus and HCO3, inhibits pepsin activity, chelates with proteins to form protective barrier against acid and pepsin, inhibits H. pylori, absorbs etiological factors
MOA sucrasulfate
sticky viscous gel that adheres to gastric epithelial cells to protect them from acid and pepsin, only one requiring acid pH for max activity
When may you use either bismuth or sucrasulfate?
Bismuth: prevent traveler’s diarrhea
Sucrasulfate: H2 or PPI-induced pneumonia in bedridden pt, any chronically bedridden pt
What antibiotics are used in the eradication of H. pylori? What are their MOA?
Clarithromycin: macrolide that inhibits protein synthesis
Amoxicillin: effective in G-
Metronidazole: effective against obligate anaerobes
Furazolidine: nitrofuran antibiotic and antiprotozoal
Tx regimen for H. pylori
Antibiotics given as multi-drug to prevent resistance. Biggest primary resistance problem is in metronidazole
How do you treat the component of GERD associated with GI contents ready to reflux?
Postural and diuretic therapy- lose weight, low fat diet, decrease size of meal, bed elevation
How do you treat the compromised LES portion of GERD?
use prokinetic, antisecretory drugs
MOA of metochlopramide
prokinetic used in GERD: D2 receptor blockers and weak 5-HT4 agonists–> stimulate GI smooth muscle, increase amplitude of esophageal contractions, accelerate gastric emptying, increase LES pressure
Metochlopramide AE
central dopaminergic antagonism- tardive dyskinesia, use short term!
