2.4 Pharmacology of Diarrhoea Flashcards
What can rotavirus do to the small bowel villi?
Can cause damage
What can invasive bacteria cause damage to?
Epithelium
What can cytotoxins to to the body?
Damage muscosa
True/false. Diarrhoea can be caused by bacteria and drugs ?
True
How would you treat diarrhoea if caused by viral infection or the ingestion of contamination of food?
Viral infections- can only be treated symptomatically
Contaminated food -Antibiotics
What is ORT?
Oral rehydration therapy
Used as diarrhoea causes dehydration with electrolyte disturbance
What patietns are at risk (in particular) of dehydration?
Young and old
Patients with concurrent diuretic treatment
Why is glucose inportant for rehydration?
Allows transport of Na via a specific co-transporter on epithelial cell (H2O follows)
How do opiates work and give an example ?
Symptomatic relief (allows bowel control and normal daily activites)
Decreases gut motility, Reduces motility of the lower GIT allowing reabsorption of water and reducing watery stools
E.g loperamide (acts on opioid receptor
How does loperamide act on a pharamcological level?
Acts on opiod receptor whioch stimulates potassium channels to open. This causes hyperpolarization
It also inhibits ca2+ and therefore Ach therefore does not cause Ach to bind to muscarinic receptors, inhibiting contraction.
What is methylnaltrexone?
Opioid receptor antagonist
Used for treatment of opioid indudedconstipation in patients recieving palliative care on top of existing laxative therapy
No central effect therefore no analgesic effect
What are the common side effects for using antimuscarinic agenbts for treating diarrhoea
Inhibits secretion- dry mouth dry eyes dry skin reduced swetting
Causes tachycardia
Mild reastless ness at low dose and agitation at high dose- CNS effects
