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Generic Name

mesalamine (me SAL a meen)


Trade Name



What is mesalamine?

Mesalamine is an anti-inflammatory drug which acts on the lining of the gut to reduce inflammation. There are three different forms available. Asacol becomes active in the small bowel just before the colon is reached. Pentasa, on the other hand, is released in the small intestine just beyond the stomach. Therefore, this drug may be particularly helpful in Crohn’s disease patients with small bowel involvement. Rowasa is the same medication given either by suppository or by enema. Its primary use is for inflammation of the rectum and lower or left side of the colon.


What is it used for?

These drugs are used to treat ulcerative colitis, ulcerative proctitis, Crohn’s disease and collagenous or lymphocytic colitis. They are much more helpful in the chronic phase of these diseases than when there is severe inflammation. At those times, steroid drugs such as prednisone are usually more effective.


How do I take it?

Follow your physician’s instructions carefully. For rectal suspension, use as a retention enema at bedtime. If possible, empty the rectum prior to instilling the suspension. The enema should be retained at least eight hours for best results. Suppositories should be used one or two times a day and retained for 1 to 3 hours or longer for best results. For oral dosage, swallow the pill or capsule whole and do not break, crush or chew. Keep all medications away from children. Never share your medications with anyone else.


What do I do for a missed dose?

If you miss a dose of this medicine, take it as soon as possible. If it is almost time for the next dose, skip the missed dose and return to the regular schedule. Do not double up the medication.


Are there interactions with food or beverages?

The drug may be taken with food or milk. There are no known interactions with food.


Are there interactions with other drugs?

An interaction generally means that one drug may increase or decrease the effect of another drug. Also, the more medications a person takes, the more likely there will be a drug interaction. Interactions with this drug may occur with sulfasalazine (Azulfidine).


Is there a problem if I have another disorder or disease?

At times, a drug may have a different or enhanced effect when other diseases are present. At other times, the drug may worsen or effect another disease. With this drug, severe kidney disease may be a problem.


What about allergies?

People who have known allergies or asthma may be at an increased risk for a reaction from any new medication. The physician should always know a patient’s allergy history. Signs of an allergic reaction are skin rash, hives or fever. Of course, a person should not take mesalamine if there has been a previous reaction to this or salicylates (aspirin).


What if I’m pregnant, considering pregnancy or breast-feeding?

Most females now know that, if possible, no drug, including alcohol, should be taken during pregnancy or lactation. The potential danger, of course, is an injury to the baby. However, some drugs are much safer than others in this regard. So, the FDA has a grading system for each drug which reflects what is known medically. It ranks drugs from A, where medical studies show no evidence for danger to the fetus or mother, to B, C, D and X, where the medical evidence indicates that the risk to the fetus outweighs any benefit to the mother. Mesalamine is ranked B. Always consult your physician before taking any drug during or when planning pregnancy.


What are the effects on sexual function?

There are no known adverse effects of mesalamine on sexual function.


Are there other precautions?

  • Intact or partially intact tablets (small beads) may appear in the stool. These are empty shells from the medication. If this is a frequent occurrence, check with your physician.
  • Enemas may stain clothing.
  • Avoid taking the drug for six weeks after chicken pox vaccination (Varivax) as it may result in Reyes Syndrome.


How long is it safe to take mesalamine?

Regular use of 1 to 3 weeks is usually necessary to determine the drug’s effectiveness. Long-term use of months to years is generally necessary and safe but does require a physician’s supervision and periodic evaluation.


How about side effects?

Adverse reactions can occur with any drug, even over-the-counter medications. Some of these are mild such as a stomach upset, which may be avoided by taking the medication with food. Minor reactions may go away on their own but if they persist, contact the physician. For major reactions, the patient should contact the physician immediately.

For mesalamine, the following are the observed side effects:


  • abdominal cramps
  • indigestion
  • nausea
  • bloating
  • diarrhea
  • headache
  • dizziness
  • rash


  • fever
  • severe headache
  • increased blood in stool
  • sudden severe stomach pain


A physician’s comment…

These drugs are a major advance in treating chronic inflammatory bowel disease. They generally can be used in high doses with minimal side effects compared to the previous product, sulfasalazine. It is generally well-tolerated and safe to use long-term. Since it rarely may have an effect on the bone marrow, periodic testing of the blood is necessary.