Osmotic laxatives

Question 1

Osmotic laxatives - indications

Answer 1

Constipation and faecal impaction

Bowel preparation (prior to surgery or endoscopy)

Hepatic encephalopathy

Question 2

Osmotic laxatives - MOA

NOTE: DONT NEED TO KNOW MOA OF LAXATIVES FOR EXAM

Answer 2

Osmotic laxatives are osmotically active substances and therefore remain in the gut lumen
They hold water in the stool - therefore maintaining the volume and stimulating peristalsis

Question 3

Osmotic laxatives - adverse effects

Answer 3

Flatulence
Abdominal cramps
Nausea

Diarhhoea is a possible complication
Phosphate enemas = local irritation and electrolyte disturbances

Question 4

Osmotic laxatives - examples

Answer 4

lactulose

macrogol

phosphate enema

Question 5

Osmotic laxatives - contraindications (avoid)

Answer 5

intestinal obstruction

why? due to risk of perforation

Question 6

Osmotic laxatives - contraindications of phosphate enemas (caution)

Answer 6

heart failure

ascites

electrolyte disturbances

Question 7

Osmotic laxatives - interactions

Answer 7

NO SIG INTERACTIONS

Caution with warfarin
Why? may increase effects of warfarin