Week 13: GI Meds Flashcards
Prototype GI Meds
14:
Famotidine
Omeprazole
Sucralfate
AlOH and MgOH
Simethicone
Dimenhydrinate
Promethazine
Metoclopramide
Ondansetron
MgOH
Bisacodyl
Psyllium
Docusate
Loperamide
Famotidine (Pepcid) Classification
Antihistamine (H2 Blocking Agent)
different from H1 receptor blockers like true antihistamines
Action of Famotidine
Competitive antagonist acting on H2 receptors and mediates parietal cell acid production
Inhibits vagal stimulated gastrin enzyme release
*Basically blocks histamine action at parietal cells in the stomach to stop acid secretion
Routes for Famotidine
Oral or Parenteral
ADRs of Famotidine
UNCOMMON! (w/ short term use)
CONFUSION (Can see in older individuals since H2 is blocked)
PNEUMONIA
Other: HA, tiredness, constipation
Why is pneumonia a potential ADR of famotidine
because increasing gastric pH means organisms that are killed off normally can be aspirated
How often is famotidine given for GERD
20-40 mg TWICE DAILY
What does the suffix “-idine” mean
H2 blocker
Omeprazole (Prilosec) Classification
Proton Pump Inhibitor (PPI), gastric acid secretion suppressent
(Suppresses acid production)
Action of omeprazole
a “prodrug” converted to active form in parietal cells
active form inhibits H+K+-ATPase (enzyme producing gastric acid)
ADRs of omeprazole
Short Term Use (4-8 weeks): HA, NVD
Long Term: CHRONIC KIDNEY DISEASE, Dementia, Mg Deficiency, Pneumonia, Weakened Bones (Ca absorption)
What is considered to be one of the most effect acid secretion suppression drugs? What is the issue with it
Omeprazole
the issue is the ADRs increase with long term use such as chronic kidney disease
What is the most effective class of drugs for suppressing gastric acid secretion
PPIs (ex: omeprazole)
What does the suffix “-prazole” mean
PPI (ex: Omeprazole, Protonix is Pantoprazole)
What is important to know aboutb the tablet of Prilosec/omeprazole
it is enterically coated in a delayed release capsule so do not crush it
Sucralfate (Carafate) Classification
Anti Ulcer
What is unique about sucralfate
it is a unique drug with no other drug being like it
It “patches” the ulcerated area in the stomach mucosa
Action of sucralfate
exact mechanisms not fully defined
exerts LOCA ACTION - forms an ULCER ADHERENT COMPLEX (gooey sticky patch) at the ulcer site to protect it against further acid attack, pepsin, or bile salts
Also inhibits pepsin activity
Where does sucralfate act
acts locally (on the GI tract) not the bloodstream by patching the ulceration on mucosa
Sucralfate must be given…
on an empty stomach
What is important to know about the absorption and distribution of sucralfate
only 3-5% is absorbed since it has local low absorption
It is distributed on the GI tract and lasts about 5 hours
ADRs of Sucralfate
Most Common: CONSTIPATION
Other: Diarrhea, Nausea, Gastric Discomfort, Indigestion, Dry Mouth, Rash, Pruritis, Back Pain, Dizziness, Vertigo
*generally well tolerated)
Why can sucralfate not be given with an antacid within a half an hour period
because the stomach mucosa needs to be pH <4 for activation
sucralfate may interfere with what
absorption of fat soluble vitamins (blocks that mucosa)