Asacol is a brand of the generic medication mesalamine. It is used to treat inflammatory bowel disease (IBD). Two different disorders are classified as inflammatory bowel disease: ulcerative colitis and Crohn's Disease. Inflammatory bowel disease has no cure. The most common symptoms of IBD are vomiting, diarrhea and blood in the stools.
Area of Action
Asacol is one of a handful of drugs that contain 5-aminosalicylic acid, or 5-ASA. The chemical structure of 5-ASA is similar to aspirin. Most medications are effective after being absorbed into the bloodstream, but Asacol, like other forms of 5-ASA, must work topically at the inflamed area of the bowel. Asacol is enteric coated to prevent the medication from being absorbed into the bloodstream before it reaches the colon. Asacol dissolves at pH 7, which is the pH of the furthest part of the small intestine and the earliest part of the colon.
Function
The exact mechanism of action of mesalamine, like other 5-ASA formulations, is unknown. Despite its similar chemical structure to aspirin, mesalamine does not appear to have the same function as aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs). Asacol appears to work in the layer of cells that lines the small intestine and bowel. It suppresses the release of chemicals that are responsible for inflammation, such as lipid mediators and cytokines.
Asacol in IBD
In order for 5-ASA drugs to be effective, the drug must be highly concentrated in the area where the disease is active. Among people with ulcerative colitis, Asacol is a good choice for those whose disease is located at the end, or distal, portion of the small intestine.
The effectiveness of 5-ASA drugs in Crohn's Disease is not as well known, but many doctors like to use Asacol in mild to moderate cases of Crohn's Disease that are confined to the distal ileum and proximal colon.
Side Effects
Clinical trials of Asacol showed few side effects. Some people may be allergic to Asacol. Symptoms of allergy include fever, rash or breathing problems. In rare cases, high doses of Asacol have been linked to kidney failure. Asacol should not be used in people who have kidney problems, and patients should have their renal function evaluated before they begin taking Asacol. Renal function should also be checked periodically for as long as they remain on the drug.
Dosage
For active cases of ulcerative colitis, the usual dose of Asacol is two 400 mg tablets three times daily. The maintenance dose of Asacol is 1.6 grams in divided doses, such as 400 mg four times a day.
References
- Basic and Clinical Pharmacology; Bertram Katzung; 2007
- Asacol Prescribing Information
- Pharmacist's Letter/Prescriber's Letter; Drug Therapy for Ulcerative Colitis; March 2007
