Medicine & USMLE

Stimulant Laxatives (Senna, Bisacodyl)

GI Drugs
  1. Ondansetron
  2. Sucralfate
  3. Docusate (Stool Softener)
  4. Bulk Forming Laxatives (Psyllium, Methylcellulose)
  5. Osmotic Laxatives (Lactulose, PEG)
  6. Stimulant Laxatives (Senna, Bisacodyl)
  7. Antidiarrheals (Loperamide, Diphenoxylate-Atropine)
  8. Bismuth Subsalicylate
  9. Antacids
  10. Proton Pump Inhibitors (PPIs)
  11. H2 Blockers
  12. Metoclopramide
  13. Misoprostol
  14. Orlistat
  15. Octreotide


Stimulant laxatives, like senna and bisacodyl, treat constipation by increasing intestinal peristalsis. They may also be used to clear out the intestines before a procedure like a colonoscopy.

Key Points

  • Stimulant Laxatives
    • Also called contact or irritant laxatives
    • Key Drugs
      • Sennosides (Senna)
      • Bisacodyl (Dulcolax)
    • Mechanism
      • Stimulation of intestinal peristalsis by drawing in water and electrolytes into the large intestine
      • Most rapid effect when taken on an empty stomach
    • Clinical Use
      • Constipation
        • Short term treatment - not recommended for long term use
        • Contraindicated in patients with bowel obstruction or fecal impaction
      • Bowel prep prior to surgery or diagnostic testing (e.g. colonoscopy)
    • Side Effects and Adverse Reactions
      • Abdominal cramps
      • Fluid and electrolyte imbalances
        • With excessive and chronic use
        • Potassium and calcium
      • Nausea
      • Diarrhea
      • Yellow-green colored stool, red-brown colored urine