GIT Lec 3 Pt 5 - Osmotics & Bulking And Softening Agents

Question 1

What are the subdivisions of osmotics?

Answer 1

1. Saline osmotics (magnesium citrate & hydroxide and Sodium Phosphate)
2. Polyethylene Glycol (PEG)
3. Lactulose

Question 2

What are the indications of saline osmotics?

Answer 2

They are mainly used to clear the colon for diagnostic procedures and surgery.

Question 3

What are the pharmacokinetics of polyethylene glycol?

Answer 3

It softens the stool, decreases cramping and gas formation and increases the quantity of bowel movements more than other laxatives; it has the following pharmacokinetics:
1. It clears the bowel by inducing diarrhea
2. Indicated for bowel cleansing prior to colonoscopy or barium enema.
3. Can be used once for patients with chronic constipation then another medication has to be used for prevent constipation
4. The powder should be mixed with 3-4 liters of water; 250ml should be given every 10 minutes

Question 4

What are the contraindications of PEG?

Answer 4

1. Intestinal obstruction
2. Fluid over-load

Question 5

what are the pharmacokinetics of Lactulose?

Answer 5

1. It is a semisynthetic disaccharide which is not absorbed by the intestines
2. It is given orally, and degraded in the intestine by intestinal bacteria into lactic, formic and acetic acids which lead to increased osmotic pressure within the lumen which leads to:
   a. Water retention within the content of the intestine
   b. Colon distention
   c. Easier defecation
3. It is also indicated for hepatic encephalopathy (turns NH3 into NH4+ which are not absorbable thereby preventing ammonia intoxication)

Question 6

What are the side effects of Lactulose?

Answer 6

The side effects are mild, including abdominal discomfort, flatulence and cramping

Question 7

What are the pharmacokinetics of bulk-forming laxatives?

Answer 7

1. Bulking-agents like bran are the most natural and safest way to treat constipation.
2. Eating bran is a great way to add fibers to the diet.
3. They form a gel that lines the intestine which leads to water and electrolyte retention and intestinal distention which leads to easier defection due to increased peristaltic activity.

Question 8

What are the side effects of bulk-forming drugs?

Answer 8

Flatulence and borborygmi
They should be taken carefully in patients who are immobile since they could cause intestinal obstruction.

Question 9

What are some examples of stool-softening medications (emollients)?

Answer 9

1. Docusate Sodium
2. Docusate Calcium
3. Docusate Potassium

Question 10

What are the indications of stool-softening medications?

Answer 10

They are good for the treatment of anal fissures and hemorrhoids.
They might take a few days to become active so they’re meanly reserved for prophylaxis rather than acute treatment

Question 11

What are the contraindications of stool-softeners?

Answer 11

They shouldn’t be taken concomitantly with mineral oils due to the possibility of the absorption of the mineral oil.