L21. Pharmacology of the GIT Flashcards Preview

04. Gastrointestinal > L21. Pharmacology of the GIT > Flashcards

Flashcards in L21. Pharmacology of the GIT Deck (43)
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31

What is docusate often combined with for treatment with opioid drugs to prevent constipation

Docusate + Senna (stimulant laxative)

32

What are the different classes of osmotic laxatives? [5]

1. Saline laxatives
2. Disaccharide
3. Polyols
4. Macrogols
5. Glycerol

33

General mechanism of action of the osmotic laxatives?

Most contain an non-absorbable component (metal ions, sugars, large macropolymers) that exert an osmotic effect on the gut to force water out

All are contraindicated in intestinal obstruction

34

Saline laxative example

Magnesium sulphate (epsom salts)

35

Disaccharide example

Lactulose

36

Polyols example

Sorbitol (artificial sweetener in confectionary)

37

Macrogol uses

Bowel preparations - often combined with electrolytes

38

Mechanism of action of stimulant laxatives

LAXATIVE

Direct stimulation of nerve endings in colonic mucosa to increase intestinal motility
can also cause accumulation of water and electrolytes in the lumen by reduction of net reabsorption

39

Example of a stimulant laxative

SENNA

40

Example of another laxative class (acts on mu opioid receptors)

Methylnaltrexone

Peripherally acts on mu opioid receptors to block action in the gut

41

Cytoprotective drug for ulcers

Sucralfate
Forms protective barrier at the ulcer site resistant to acid, pepsin and bile

42

Use of spasmolytics in ulcers: MOA and example

MUSCARINIC RECEPTOR ANTAGONIST
Hyoscine butylbromide
Reduces gut motility (anti-slud) = buscopam
Not absorbed so only has periperal effects

43

Use of prostaglandin E analogues in ulcers: MOA and example

Mimics endogenous PG
Increases mucosal secretion, mucosal blood flow and decreases acid secretion

Misoprostol