QuestionSBA
QuestionChoice
Incorrect - Methylcellulose is a bulk laxative. These work by increasing water retention in the intestinal lumen to soften & increase the bulk of stools. This drives colonic distention, which in turn stimulates intestinal motility and faecal transit.
10008407
c
Methylcellulose
QuestionChoice
Correct - Senna is a stimulant purgative. These increase intestinal motility through stimulation of the myenteric plexus. Specifically, senna decreases motility in the proximal colon and increases motility in the distal colon.
10008405
a
Senna
QuestionChoice
Incorrect - Loperamide is used to treat diarrhoea and is not a laxative. It increases motility in the proximal colon, increasing the absorption of water, and decreases motility in the distal colon.
10008409
e
Loperamide
QuestionChoice
Incorrect - Arachis oil is a faecal softener. This does not affect colonic motility. It works by lowering the surface tension of the stool, softening its consistency and hence making it easier to pass.
10008408
d
Arachis Oil
QuestionChoice
Incorrect - Macrogol is an osmotic laxative. These work by promoting the movement of fluid across the bowel wall and into the lumen. This causes colonic distension, simulating and accelerating transit and hence defecation.
10008406
b
Macrogol
Concept
Chapter
2693
4667
Laxatives
Topic
229
Pharmacology of the gastro-intestinal system
14228
A 26-year-old woman visits the GP surgery for support managing her constipation. She is advised to increase the amount of fluid and fibre in her diet. She is also prescribed a laxative.

Which of the following laxatives decreases motility in the proximal colon and increases motility in the distal colon?
a