Laxatives (osmotic)

Question 1

What are the generic and brand names of osmotic laxatives?

Answer 1

• Lactulose (Dulphalac)

Question 2

What is the method of action of osmotic laxatives?

Answer 2

• Formed by ‘osmotically active substance’ e.g. sugars that are digested by enzymes to lower the pH and increases osmotic pressure → Stimulates peristalsis and increases water in stools

Question 3

What are the indications of use of osmotic laxatives?

Answer 3

• Constipation
• Bowel prep prior to surgery/endoscopy
• Hepatic encephalopathy

Question 4

What are the contraindications for osmotic laxatives?

Answer 4

• UC

* CD

Question 5

What are the side effects of osmotic laxatives?

Answer 5

• Flatulence
• Cramps
• Nausea
• Local irritation and electrolyte disturbances (phosphate enema)

Question 6

What is the route of elimination for osmotic laxatives?

Answer 6

• Faecal