Aminosalicylates (Mesalamine and its Derivatives)
Mesalamine is an aminosalicylate (the common name of the compound 5-aminosalicylic acid or 5-ASA). This compound inhibits factors in the immune system, importantly, the cytokines that cause inflammation. Mesalamine preparations and formulations are very useful for treating active mild-to-moderate ulcerative colitis. Although not as effective as corticosteroids in active disease, they can be used for maintenance therapy and for preventing relapse. (Corticosteroids cannot be used for this phase.) There is also some evidence that mesalamine reduces the risk for colon cancer. Mesalamine seems to benefit women more than men. All mesalamine preparations appear to be safe for children and for women who are pregnant or nursing.
Mesalamine has few side effects, but it is absorbed so quickly in the upper gastrointestinal tract that it usually fails to reach the colon if used orally and as a single drug. Other substances, therefore, are added to mesalamine or it is formulated so that it can reach the lower intestine before it is absorbed. Sulfasalazine (Azulfidine), which contains mesalamine and sulfapyridine (a sulfa antibiotic), is the standard preparation.
Administering mesalamine topically using enemas or suppositories is also an effective method for reaching disease in the lower left intestine, which occurs in about two-thirds of patients with ulcerative colitis. A combination of oral and topical mesalamine in such people is more effective than an oral form alone.
Sulfasalazine. Sulfasalazine (Azulfidine) is the standard mesalamine preparation. Sulfasalazine is known as a prodrug because it becomes an active drug when it breaks down by intestinal bacteria. In this event, it is broken down into two components: mesalamine and sulfapyridine.
- Mesalamine, the active component, blocks the inflammatory process
- Sulfapyridine (a sulfa antibiotic) plays no role in treating the disease, but it does prevent mesalamine from being absorbed until it reaches the colon
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