Chapter 40: Constipation Drugs

Question 1

What is the prototype bulk forming laxative?

Answer 1

Psyllium Preparations

Question 2

How does psyllium work?

Answer 2

They are soluble fibers that are largely unabsorbed by the small intestine. When H2O is added these substances swell and become gellike.

Question 3

What is the prototype stool softener?

Answer 3

Docusate Sodium

Question 4

How does docusate sodium work?

Answer 4

Allows H20 penetrate stool.

Question 5

What is the stimulant laxative prototype?

Answer 5

Bisacodyl

Question 6

How does bisacodyl work?

Answer 6

Stimulant cathartics are the strongest and most abused laxative products. They irritate the GI mucosa, pull water into the intestinal lumen and stimulate perstalsis. They produce a watery stool and may lead to fluid, electrolyte and acid-base imbalances.

Question 7

What is the prototype saline laxative?

Answer 7

Polyethylene glycol

Question 8

How does Polyethylene glycol work?

Answer 8

Saline laxatives increase the osmotic pressure in the intestinal lumen, resulting in the retention of water, which distends the bowel and stimulates peristalsis. They produce a semi fluid stool and may lead to fluid and electrolyte imbalances.