Lecture 17/18 - GI medications Flashcards
What is responsible for protecting the stomach from acidic conditions?
Bicarbonate + Mucous
When do ulcers occur, most basic mechanism?
Acid > Protective layer
What can cause ulcers?
Drugs = NSAIDs + Corticosteroids H.pylori Mast cell tumors GI diseases Long interavals of no food in horses
What is the most basic mechaism by which ulcers are healed?
decrease acid
What are common signs of ulcers in dogs?
Vomiting +/- blood
Weight loss + Anaemia
Black tarry stool
What are common signs of ulcers in cats?
Vomiting +/- blood
Anemia + Weight loss + loss of appetite
Abdominal pain
Tarry stool
What is EGUS?
Equine gastric ulcer syndrome
What type of horse is most prone to ulcerations?
Racing horses (~60%)
What is the most basic mechanism by which horses get ulcers?
Always producing acid, so must be able to eat at all times to prevent erosion of stomach lining
What are signs that a horse may have a stomach ulceration?
Poor appetite + Lethargy + Weight loss + Poor performance + Attitude
What are the two parts of a horses stomach?
Non-glandular + Glandular
What is ESGUS?
Non-glandular
What is EGGUS?
Glandular
What portion of the stomach is most prone to ulcerations?
Non-glandular
What is an important mechanism by which H+ is taken into the parietal cell?
Histamine from ECL cell stimulates H2
What is the important protective portion of the molecular cascade of parietal cells?
PGE2 + PGI2 –> stimulates EP3
What does EP3 do? (two different cells)
Superficial epi cell = mucous + bicarb
Parietal cell = prevents H+ secretion
What inhibits PG’s?
NSAIDs
What do antacids block?
H+ directly
What do proton pump inhibitors inhibit?
H/K ATPase
What is the pH at the mucous layer?
7
What is the pH in the gastric lumen?
2
What does Mg do in the stomach?
Binds H+
Not absorbed
Also acts as a laxative
What does Al do in the stomach?
Binds H+
Not absorbed
Causes constipation
Combine with Mg