5-ASA Agents
(5-aminosalicylic acid)
These include sulfasalazine, mesalazine, and mesalamine-based drugs, available as oral medications, suppositories, and enemas.
Originally developed as treatments for arthritis, their effectiveness against inflammatory bowel diseases like ulcerative colitis and Crohn's disease was discovered. Since then, they have become the widely used, standard medication for these conditions.
Characteristics and Limitations:
The precise mechanism of how these drugs work for ulcerative colitis or Crohn's disease is not clearly understood, yet they are commonly used in mild, early stages without a clear mechanism of action. In early-stage ulcerative colitis, initial use may induce remission for 1-2 years; however, even with continued use, relapse typically occurs after 1-2 years. Once a relapse occurs, increasing the dosage often fails to induce remission again.