Summary

Senna is a laxative that works by irritating the bowel to stimulate bowel movement. As a laxative, it treats constipation but too much laxative can cause diarrhea. A benign but high-yield side effect is melanosis coli, which describes a black-brown discoloration of the colon.

Key Points

• Senna
  • Mechanism
    • Stimulant laxative
      • Enteric nerve stimulation → colonic contraction
      • Works by irritating sensory nerve endings, which stimulates colonic motility and reduces colonic absorption
  • Clinical Use
    • Laxative for constipation
  • Adverse Effects
    • Diarrhea
    • Melanosis Coli
      • Harmless black coloration of colon, that may be observed on colonoscopy