PUD+ GERD Dr. J Flashcards
True or false: PPIs are prodrugs
True
What type of environment do PPIs need to be in to be activated?
Acidic
What 3 components make up a PPI?
- Benzimidazole
- Methylsulfinyl
- Pyridine
When Omeprazole is activated by a proton catalyzed process, what does it generate?
A sulphenamide
The sulphenamide interacts _____ with the sulphydryl groups of cysteine residues
Covalently
To prevent premature degradation of proton pump inhibitors by acid in the gastric lumen, oral dosage forms are supplied in what kind of formulations?
Enteric coated
How are PPIs absorbed and how does it reach its site of action?
Systemically; through the blood
What CYP enzymes extensively metabolize PPIs?
- 2C19
- 3A4
Protonix is is freely ____ in water
Soluble
The stability of protonix in aqueous solution is dependent on what?
pH
The delayed release and enteric coated tablets dissolve only at what pH for PPIs?
Alkaline
What inhibits acid production by reversible competing with histamine for binding to H2 receptors on the basolateral membrane of parietal cells?
H2RAs
True or false: H2RAs are less potent than PPIs
True
The H2RAs predominantly inhibit what?
Basal acid secretion
Because of what H2RAs inhibit, what are they efficacious for?
Suppressing nocturnal secretion
True or false: H2RAs need to have enteric coating
False
Why isn’t ranitidine on the market?
NDMA levels increase in ranitidine even under normal storage conditions
H2RAs are rapidly absorbed after oral administration with peak serum concentrations within how many hours?
1-3
Absorption of H2RAs may be enhanced by ____ or decreased by ______
Food; antacids
What type of cells are the most prevalent in the acid secreting regions of the stomach?
Enterochromaffin like cells (ECL)
What cytoprotective effects does PGE2 have? 3
- Stimulation of mucin
- Stimulation of bicarbonate secretion
- Increase mucosal blood flow
Misoprostol is an agonist at what receptor?
EP3
True or false: mistoprostol is a prodrug
True
What does misoprostol decrease?
Acid secretion
What does sucralfate undergo in an acidic environment?
Extensive cross-linking
What does sucralfate produce?
Viscous, sticky polymer that adheres to epithelial cells and ulcer craters
What are the 4 mechanisms of sucralfate cytoprotection?
- Protective effects in mucus
- Antipeptic effect
- Barrier effect
- Enhanced tissue growth
Antacids can prolong neutralizing effects on the pH in the presence of _____.
Food
H. Pylori releases cytokines, toxins, and chemokines that result in
A massive inflammatory response
Neutrophils are released from the capillaries to kill H. Pylori, but what else does it destroy?
Mucus secreting mucous membranes of the stomach
