GI: LAXATIVES, OSMOTIC

Question 1

LAXATIVES, OSMOTIC: INDICATIONS

Answer 1

• Constipation and faecal impaction
• Bowel preparation prior to surgery/endoscopy
• Hepatic Encephalopathy

Question 2

LAXATIVES, OSMOTIC: MOA

Answer 2

• Osmotically active substances that are not digested/absorbed -> remain in gut lumen
• Hold water in stool -> maintain volume, stimulate peristalsis
• Lactulose - reduces ammonia absorption
• Increases gut transit rate, acidifies stool, inhibiting proliferation of ammonia producing bacteria
• Helpful in Liver failure patients

Question 3

LAXATIVES, OSMOTIC: ADVERSE EFFECTS

Answer 3

• Flatulence
• Abdominal cramps
• Nausea
• Diarrhoea is a possible complication
• Phosphate enemas = local irritation and electrolyte disturbances

Question 4

LAXATIVES, OSMOTIC: WARNINGS

Answer 4

• CI in intestinal obstruction as there is a risk of perforation
• Phosphate enemas = fluid shift
• Used with caution in heart failure, ascites and when electrolyte disturbances are present

Question 5

LAXATIVES, OSMOTIC: IMPORTANT INTERACTIONS

Answer 5

• No significant adverse drug interactions

- Warfarin effects slightly increased

Question 6

LAXATIVES, OSMOTIC: EXAMPLES

Answer 6

• Lactulose
• Mocrogol
• Phosphate Enema