13.2: Drugs Affecting Gut Motility Flashcards
(20 cards)
How does domperidone exert its anti emetic function?
D2 antagonism, by acting centrally on the postrema of the 4th ventricle, and locally on the stomach to increase the rate of gastric emptying
What is the 1st line anti emetic drug?
Metclopramide
How does metclopramide exert its anti emetic function?
D2 antagonism (increasing gastric emptying and acts centrally on the 4th ventricle)
What are some side effects of D2 antagonist anti emetics?
Galactorrhea
Dystonia (rare)
Beware in Parkinson’s
What anti emetic is used for motion sickness and how does it work?
Hyoscine
Antagonises muscarinic cholinergic receptors
Which anti emetic is 2nd line?
Cyclisine
How does the anti emetic cyclisine act?
H1 antagonist
What are conservative methods to manage constipation?
Increase fluid intake
Increase fibre intake
Do more exercise
What are some drugs that can cause constipation?
Opioids
Anticholinergics
Antidepressants
Iron
What type of laxative is senna?
Stimulant laxative which increases intestinal motility
What electrolyte abnormality can repeated use of Senna lead to?
Hypokalaemia
How do bulk laxatives work?
They are insoluble substances that bulk up the stool and lead to gut distension which activates stretch receptors to stimulate peristalsis
Which enema is indicated for rapid bowel evacuation?
Phosphate enemas
How do phosphate enemas act?
Cause water retention in the small and large bowel which stimulates rapid peristalsis and bowel evacuation
What is Imodium used for?
Diarrhoea
What receptors in the bowel does Imodium act on?
Opioid receptors
How does Imodium work?
Acts on opioid receptors to reduce bowel motility so there is more time for fluid to be reabsorbed
Also reduces anal tone
Which type of anti diarrhoea drug can be used for IBS?
A bulk forming e.g. ispaghula
What type of laxative should be used if the faeces is soft?
Stimulant laxative e.g. senna
What type of laxative should be used if the faeces is hard?
Osmotic laxative
Bulking forming laxative
