Ulcerative Colitis Treatment

Selected Safety Information About Asacol

Important Precautions

There are some important precautions you should be aware of regarding Asacol therapy, including:
  • It is recommended that all people have their kidney function tested prior to starting Asacol® and periodically while on Asacol therapy.
  • If you have a history of kidney impairment or kidney disease, you should tell your doctor before using Asacol.
  • If you are pregnant, become pregnant or are a nursing mother, talk with your doctor before using Asacol.
  • Some people who have had a reaction to sulfasalazine may have a similar reaction to Asacol or other products that contain mesalamine. Such a reaction may include worsening of colitis symptoms (i.e., cramping, abdominal pain, and bloody diarrhea) and occasionally fever, headache, general discomfort, itching, rash, and conjunctivitis (an inflammation of part of the eye).
  • There was a worsening of the symptoms of colitis as reported in 3% of Asacol-treated people in clinical trials.
  • If you have pyloric stenosis (a narrowing of the outlet from the stomach), you should tell your doctor before using Asacol.

Adverse Events

In clinical studies that compared people taking Asacol® to those taking a sugar pill (placebo), there was no significant difference in the number reporting side effects.

In studies of flare-ups, some people taking Asacol reported headache, abdominal pain, general pain, rash, upset stomach and worsening of colitis symptoms. In a maintenance study, some people reported headache, runny nose, general pain, sore throat, infection, and nervousness.

Talk with your doctor about your medical history and any questions about your medication. It's also important to visit your doctor periodically to monitor your condition and discuss your treatment plan.


Asacol (mesalamine) delayed-release tablets, available only by prescription, are indicated to treat mild to moderate flare-ups of ulcerative colitis and maintain remission of ulcerative colitis. Asacol is generally well tolerated. In studies of flare-ups, some people taking Asacol reported headache, abdominal pain, general pain, rash, upset stomach, and worsening of colitis symptoms. In a six month maintenance study, some people reported headache, runny nose, general pain, sore throat, infection, and nervousness. You should not take Asacol if you are allergic to Asacol or to salicylates such as aspirin. Tell your doctor if you have kidney problems or a history of kidney disease. It is recommended that all people have their kidney function tested prior to starting Asacol tablets and periodically while on Asacol therapy. Serious side effects may occur. If you have questions about taking Asacol, please talk to your doctor.
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