Exam 5- GI Pharm Flashcards
Parietal cell H+ pump stimulation via…
diagram
- histamine
- ACh
- Gastrin
prostaglandins effects on H+ defense
two diagrams
acetocholine’s role in defense mechanisms to H+
NSAIDS systemic effect on Peptic Ulcer Disease
-inhibit COX = (-) prostaglandin synthesis
=increased H+ and decreased HCO3-/mucus
NSAIDS topical affect on PUD
NSAID enters cell protonated but then in intracellular neutral environment it gets trapped and damages cell
helicobacter pylori effects
=90% of all duodenal ulcers
=75% of all gastric ulcers
- urease induced synthesis of ammonium hydroxide
=buffers environment
=toxic to epithelial cells
=(+) gastrin release
- gastrin (+) parietal cell proliferation and more H+
- decrease in somatostatin which typically (-) gastrin
H. pylori PUD treatments
1. eradicate H. pylori
antibiotics
2. inhibit Gastric H+ release
- proton pump inhibitor
- histamine receptor antagonists
3. increase body’s defense
-prostaglandin analogs
H. pylori PUD combinaton therapy includes
- proton pump inhibitor
omeprazole
- two antibiotics
*pH will affect antibiotics which is why we coadminister a proton pump inhibitor*
omeprazole
lansoprazole
MOA
=proton pump inhibitors
- irreversible inhibition of H+/K+ pump
- only inhibit active pumps ∴ take befor a meal
- most effective treatment bc raising pH will (-) H. pylori
proton pump inhibitor side effects
- H+ kills bacteria so inhibiting this would possibly allow other infections
- omeprazole= selectively inhibits CYP45 so diazepam effects would be more pronounced
- decreases absorption of compounds that require acidic environments
histamine receptor antagonists
***insert diagram
cimetidine
famotidine
less effective than proton pump inhibitors but known to be safe and inexpensive
- block H2 receptors on parietal cells
- inhibit CYP450… so drug interactions
- most prominant in cimetidine
- absent in famotidine
prostaglandin analogs
MOA (draw it)
**diagram
misoprostol
-activates EP3
- (+) mucus and HCO3- release from epithelial
- (-) histamine induced H+ release from parietal cell
misoprostol clinical use and toxicity
use for NSAID related mucosal damage
mild toxicity… diarrhea (13-40%)
-contraindicated during pregnancy
GERD
-acid into eophagus
common causes
- -delayed gastric emptying
- -obesity
- -weakness of esoph. sphincter
- -hiatal hernia
>50% incedenc in people over 50
treatment strategies for GERD
- Histamine receptor antagonists
- proton pump inhibitors
(preferred with erosive esophagus)
cimetidine famotidine
histamine receptor antagonists
treatmetn for GERD
omeprazole lansoprazole
proton pump inhibitors used for treating GERD
nausea common causes
intestinal irritation- 5-HT and dopaminergice nerves =vomiting
Migraine- often DA mediated
vestibular- histamine and ACh
pregnancy- unknown; treated with ginger, vit B6, promethazine, 5-HT antagonists, corticosteroids
vestibular nausea treatment with antihistamines
- antihistamines -
(-) H1 receptor
dimenhydrinate
-limit vomiting from vestibular system
-can treat motion sickness but hav anticholinergic side effects - dry mouth, decreased urination, blurred vision, glaucoma
treatment of visceral nausea with anticolinergic drugs
anticolinergic
(-) Muscarinic-R
scopolamine
-can treat motion sickness but hav anticholinergic side effects - dry mouth, decreased urination, blurred vision, glaucoma
treatment of visceral nausea with 5-HT antagonists
-block 5-HT3 receptors in the small dowel, vagus nerve and chemoreceptro trigger zone
-ondansetron
treatment of visceral nausea with DA-R antagonists
-blocks D2-like receptors
= limiting emetic input to the medullary vomiting center
-large side effects.. sedation orthostatic hypotension and extrapyramidal symptoms
-chlorpromazine
-promethazine
