Approved by the FDA in 1997, Asacol (Aze-a-call) is a man-made compound that is taken by mouth to treat inflammatory disorders of the colon such as ulcerative colitis, Crohn's colitis, and other inflammatory conditions. It is sometimes given in conjunction with other medications such as the steroid, prednisone. It is also used in cases of Crohn's disease which only involve the end of the small intestine, called the terminal (meaning "end of") ileum.

Asacol is the better half of Azulfidine
The active ingredient in Asacol, mesalamine (5-aminosalicylic acid, also referred to as 5-ASA), is the major active component of Azulfidine (sulfasalazine) which has been used for over 50 years in the treatment of inflammatory bowel disease. It turns out that some patients have an adverse reaction to Azulfidine, mostly due to its similarity to sulfa compounds. Scientists were able to remove the sulfa-like portion of Azulfidine, while maintaining the full beneficial effect. The result was meslamine, an aspirin-like antiinflammatory drug, named Asacol. Each brown-red capsule-shaped enteric coated tablet of Asacol contains 400 mg of mesalamine.

Targeted Delivery
One of the unique features of Asacol is the fact that the pill does not release its medication until it reaches the diseased area. Each tablet has a special plastic coating which delays release of mesalamine until the tablets reach the end of the 20 feet of small intestine, or the ileum. This allows delivery of most of the medicine right where the problem lies - the ileum and the colon. How mesalamine works is unknown, but it appears to be topical rather than systemic. Once released in the colon, mesalamine is minimally absorbed. Most of it works directly on the lining of the ileum and colon - like putting a salve on a rash. Eventually most of it is excreted with the stool.

Studies have shown that Asacol can help bring a case of colitis under control and help maintain a remission over time. Realize that colitis rarely goes into permanent remission, but the risk of flare-ups can be substantially reduced by continued use of Asacol at the maintenance dose as directed by your doctor.

What Asacol is not
Asacol is not a steroid like prednisone. It is not habit forming; it does not cause drowsiness. Since it lacks the sulfa-like properties of Azulfidine, most patients intolerant or allergic to Azulfidine and other sulfa drugs can be safely treated with Asacol. In addition, Asacol does not reduce a man's sperm count as does Azulfidine. There are no known interactions with other medications. As yet, there is no generic substitution available.