Lecture 33 - Drugs and the gut Flashcards Preview

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Flashcards in Lecture 33 - Drugs and the gut Deck (12)
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1
Q

H2 Receptor antagonist characteristics?

A

competitive antagonist, rapid action, tolearnce development (tachyphylaxis)

2
Q

H2 antagonist problems?

A

not effective in heartburn & moderate/severe reflux, multiple dosing, half acid suppression maximum, recurrence of peptic ulcers

3
Q

H2 receptor location?

A

Gastric parietal cells

4
Q

Proton pump location?

A

gastric parietal cells

5
Q

Proton Pump inhibitor mechanism of action?

A

Omeprazole (e.g.) absorbed in blood, reaches parietal cell, passes into canaliculi, converted into sulphonamide by acid, reacts w cysteine

6
Q

Proton pump inhibitor effectiveness?

A

Irreversible blockage of proton pump allows long duration of effect, isn’t overridden by histamine, gastrin or Ach stimulation, >90% effectiveness

7
Q

Uses of P.P inhibitors?

A

gastro-oesophageal reflux disease, NSAID cause ulcer diseases, acute ulcer bleeding

8
Q

Problems w prolonged acid secretion inhibition?

A

Malabsorption (B12, Fe, Ca), bacterial overgrowth, lesser sterilisation of food, ECL atrophy to high gastrin

9
Q

Problem and solutions w pancreatic enzyme ingestion?

A

Degradation by acid - enteric coated capsules or take w P.P inhibitors

10
Q

Enteric coating?

A

Capsule dissolves rapidly in stomach releasing hundreds of minimicrospheres which rapidly disintegrate in duodenum to release enzymes

11
Q

Methods to prolong drug activation to large intestine? e.g. 5-ASA?

A

join two molecules with azo bond (only cleaved by colonic bacteria), enteric coating, pH/time-dependent release

12
Q

COX2 function?

A

catalyses formation of inflammatory prostaglandins, inhibiting effects cytoprotective prostaglandins, reducing risk of bleeding but increasing risk of myocardial infarction