B15 Drugs + Oral Rehydration

Question 1

What is oral rehydration therapy?

Answer 1

Fluid replacement to treat electrolyte depletion in diarrhoea. The recommended formulation is:
Glucose
Sodium chloride
Sodium citrate
Potassium chloride

Question 2

How does oral rehydration therapy work?

Answer 2

Glucose stimulates the uptake of sodium into the intestine enterocytes via facilitated diffusion, using the 2Na+/glucose symporter. Movement of sodium will prevent the loss of water.

Question 3

What is loperamide?

Answer 3

Opioid agonist which is given for diarrhoea. It acts on mu receptors in the smooth muscle to reduce peristalsis inhibits acetylcholine release and stimulates water reabsorption. It can cause headache and nausea and should be avoided in ulcerative colitis.

Question 4

What is kaolin?

Answer 4

Anti-diarrhoea drug which is a natural metal compound which adsorps onto water and bacteria to create firmer stools. Typically given with morphine so should be avoided with respiratory depression or intracranial pressure. Should be avoided with constipation.

Question 5

What is the action of lactulose?

Answer 5

It is an osmotic laxative which is given for constipation. It is hydrophilic and promotes water in the intestinal lumen to create a softer stool. It can lead to diarrhoea and flatulence.

Question 6

What is the action of diphenoxylate?

Answer 6

Anti-diarrhoea drug which is commonly mixed with atropine. It is an opioid agonist which inhibits acetylcholine and enhances segmentation.Can cause constipation and dry mouth.

Question 7

What is the action of Isphagala husk?

Answer 7

Bulk forming laxative which binds to stools and increases the weight for peristalsis. It should be avoided in colonic atony and intestinal obstruction. Can cause bronchospasm.

Question 8

What is bicasodyl?

Answer 8

Stimulant laxative for constipation which increases the parasympathetic nerve for motility by contraction of longitudinal smooth muscle and decreases expression of aquaporin channels. Should be avoided in constipation and iBS. Causes nausea and discomfort.

Question 9

What is Docusate?

Answer 9

Stool softener given for constipation which increases the water and lipid content for stools. Can lead to abdominal cramps and nausea.