Laxatives

Examples: bran, ispaghula husk, methylcellulose

Increase volume of non-absorbable material in gut -> distend colon -> stimulate peristaltic movement

Contraindications: dysphagia, bowel obstruction, colonic atony, faecal impaction

Adverse effects: flatulence, abdo distension, GI obstruction

Examples: lactulose, Macrogol

Increase water content in bowel via osmosis -> distended colon -> stimulate peristaltic movement

Contraindications: bowel obstruction

Adverse effects: flatulence, cramps, abdo discomfort

Examples: senna, danthron, bisacodyl, sodium picosulphate

Increase water and electrolyte secretion by gut mucosa, increase peristalsis

Contraindications: bowel obstruction

Adverse effects: 

• short term: cramps, abdo discomfort
• long term: damage to nerve plexi
• can cause deterioration in normal gut function

Examples: liquid paraffin, docusate sodium

Promote defecation by softening (docusate sodium) or lubricating (liquid paraffin) the stool

Used to treat constipation, faecal impaction, haemorrhoids and anal fissures

Adverse effects: long term use of liquid paraffin can impair absorption of vitamins A + D so should only be used short term

Contraindications: children <3yrs