5-ASA Compounds
A number of medications used to treat Crohn's disease and ulcerative colitis have as their active ingredient 5-aminosalicylic acid (5-ASA), an agent that inhibits substances in the immune system that cause inflammation. These include sulfasalazine (trade name Azulfadine), a compound that has been used for more than half a century.
Sulfasalazine is a so-called "sulfa drug." The sulfapyradine (an antibacterial organic sulfur compound) in sulfasalazine causes a number of side effects, which range from mild to severe headaches, nausea, and vomiting. These are usually dose-related, although some people cannot tolerate the medication at all. Azulfadine can be purchased in an enteric-coated tablet, which (for many people) reduces the incidence of nausea caused by uncoated tablets. For years, scientists sought ways to deliver 5-ASA without the sulfa-drug side effects.
During the 1990s, a number of new 5-ASA medications were approved. None are yet available as generics. They can be found under the following trade names and in the following formulations:
•Asacol (mesalamine), available as a 400-milligram coated caplet
•Pentasa (mesalamine), available as a 250-milligram capsule
•Rowasa (mesalamine), available as a 500-milligram rectal suppository or a 4,000 milligram enema (effective for Crohn's colitis, which affects the rectum and left side of the colon)
•Dipentum (osalazine), available as a 250-milligram capsule
Evidence shows that all of the new 5-ASA compounds are effective in large doses for treatment of flare-ups and in lower doses for maintenance therapy. Because these medications are expensive, many doctors prefer to try sulfasalazine first. The chemical structure of mesalamine is similar to aspirin; people with an allergy to aspirin should inform their doctors.
Steroids
Steroids are powerful, potentially toxic drugs that reduce inflammation and suppress the body's immune system. Prednisone and prednisolone are the...