Lecture 20 - GI Pharmacology Flashcards
What is the most common location of pain for gastric or duodenal ulcers?
Epigastric pain
What are some symptoms of gastric or peptic ulcerations?
Bleeding
Perforation
Scarring and possible obstruction
What are some risk factors of gastric acid or peptic ulcers?
Early gastric emptying
Imbalance between normal acid levels and feedback
Helicobacter pylori
NSAIDs
Smoking and alcohol delay healing of ulcers.
Why do NSAIDs increase risk of gastric ulceration?
Reduced prostaglandins which normally inhibit the production of gastric acid
What cells produce histamine stimulating gastric acid production?
Enterochromaffin cells
What are the 3 main stimulatory transmitters for gastric acid production?
ACh
Histamine
Gastrin
What is an example of a combined alginates and antacids?
Gaviscon
What is the purpose of antacids and alginates?
Antacids = buffering stomach acid
Alginic acid = inc stomach content viscosity and reduce reflux
What is contained in gaviscon?
Alginic acid = sodium alginate
Antacids = aluminium hydroxide/magnesium carbonate
What are the adverse effects of magnesium salt and then aluminium salts used as antacids?
Mg salts = diarrhoea
Aluminium salts = constipation
AC
MD
Why are aluminium hydroxide. And magnesium carbonate both taken at the same time if they are both antacids?
Mg salts cause diarrhoea and Aluminium salts can cause constipation
So balance the side effects
What are the warnings and contraindications to alginates and antacids?
Na+ and K+ containing preparations should be carefully used in renal failure
High conc sucrose in some solutions so be careful with hyperglycaemia in DM
What are the important drug drug interactions of alginates and antacids?
Reduce absorption of many drugs
Can inc urine alkalinity increasing aspirin excretion
What are some proton pump inhibtors?
Omeprazole
Lansoprazole
What is the mechanism of action of proton pump inhibitors like omeprazole and lansoprazole?
Why are they so effective?
Irreversibly inhibit the H+/K+ ATPase in gastric parietal cells
Inhibit the final stage in stomach acid production