Laxatives

Question 1

Bulk Forming Laxatives

Answer 1

Methylcellulose
MI, eye surgery, cerbral aneurysm, prevent Valsalva
Indigestible hydrophilic which induce water retention, increasing bulk
Swelling promotes peristalsis
SE: Nausea and vomiting

Question 2

Faecal Softeners

Answer 2

Docusate
Lower surface tension allowing water and fat to penetrate stool
Softens stool making bowel movement easier
Stimulates water and electrolyte secretion
To avoid straining

Question 3

Lubricants

Answer 3

Glycerol, Liquid Paraffin
Lubricates stool and mucosa
Also inhibits water reabsorption from lumen, stimulating peristalsis

Question 4

Osmotic Laxatives

Answer 4

Lactulose
Semi-synthetic disaccharides no absorbed from GI
Evacuate bowels in patients for surgery or exams or in drug overdose/poisoning
Attracts and retains water, increasing pressure, stimulating peristalsis

Question 5

GI Stimulants/Irritants

Answer 5

Senna
Preferred drugs for emptying bowel prior to surgery or exams
Stimulates mucosa to increase fluid secretion and peristalsis
PK: Least natural, work in 6-12 hours
SE: Cramping, fluid depletion, electrolyte disturbance