5-ASA stands for 5-aminosalicylic acid. Another name for this class of drugs is aminosalicylates.

Acetylsalicylic acid, the active ingredient in aspirin, is chemically related to the 5-ASA drugs.

The 5-ASA medications control inflammation. They are important drugs for treating ulcerative colitis but are usually not as effective for Crohn’s disease. Some people with mild cases of Crohn’s disease do benefit from taking 5-ASA medications.

Below are the list of 5-ASA medications and their Brand name counterparts.

Generic Brand name
sulfasalazine Alzulfidine
mesalamine (sometimes spelled mesalazine) AprisoAsacol HD






balsalazide ColazalGiazo
olsalazine Dipentum


Sulfasalazine was developed in the 1930s. It has two parts, sulfapyridine and 5-ASA.

Researchers discovered that sulfapyridine was responsible for many of the side effects of sulfasalazine, while the 5-ASA part was responsible for many of the benefits.

Clinical trials in the 1960s showed that the 5-ASA medications were an effective treatment for IBD, so they have been the mainstay of ulcerative colitis treatment for decades. They may not be as effective in the treatment of Crohn’s disease.

How do 5-ASA drugs work?

The 5–ASA medications work by reducing inflammation of the intestine. They do s, by preventing the production of substances involved in the inflammatory process . They can dramatically reduce the frequency of flares.

How is it administered?

Many of the 5-ASA drugs are administered orally as a pill, incuding sulfasazine (Alzulfine), Apriso, Asacol HD, Delzicol, Dipentum, Lialda, Pentasa, and Dipentum. Canasa is administered as a suppository. Rowasa is administered as an enema.

5-ASA drugs tend to get absorbed quickly, so the different 5-ASA medications are formulated in different ways to make sure the active ingredient reaches the colon. For example, Pentasa is a time-relase pill. Asacol uses acidity in intestine to release the 5-ASA drug, mesalamine, into the colon. Dipentum relies on bacteria in the colon to split mesalamine from its carrier.

The newer 5-ASA medications, which include Apriso, Asacol HD, and Lialda, don’t need to be taken as often and have delivery methods that are supposed to deliver the drug to the entire colon.

When will I feel better?

When people start feeling better varies. The range is anywhere from threeto 21 days after starting therapy.

The maximum effect may take anywhere from two to six weeks for the enemas and suppositories, six weeks for the tablets, and eight weeks for the capsules.

Between 40% and 70% of people with mild-to-moderate cases of ulcerative colitis response to 5-ASA therapy.

Side effects

Many people take 5-ASA medications for many years without any side effects. Often side effects can by decreasing the dose, although that should only be done after talking to your care team.

Headache (33%) and nausea (33%) are the most common side effects.

Others include abdominal pain (8%), rashes (3%), and abnormal liver function tests (4%).

All of the 5-ASA drug can worsen a flare, although that it is rare (1% to 5% of patients) and resolves quickly after the medication is stopped.

Because Canasa and Rowasa are administered rectally and work topically on the surface of the colon, they have few, if any, side effects.

Sulfasalazine (Azulfidine) is associated with more side effects than the other 5-ASA medications because of the sulfa compound it is made with.It may, for example, reduce fertility in men (low sperm count), although the problem reverses completely within three months of stopping the medication. In rare instance, sulfasazine may lower white blood cell counts, making people more vulnerable to infection. Sulfasalazine needs to be taken with a folic acid supplement because it may interfere with the absorption of folate. Some people are allergic to sulfa, so they must avoid sulfasalazine for that reason.

It is now a second- or third-line drug reserved for use in patients who can’t take another 5-ASA, usually mesalamine, for some reason. It is still prescribed but usually only after other drugs have been tried.

Possible drug interactions

The 5-ASA drugs interact with many other medications.

Let your doctor know if you are taking any of these drugs that might interact with the 5-ASA medications:

  • digoxin (Cardoxin, Digitek, Lanoxin)
  • iron
  • oral anticoagulants (Coumadin)
  • oral hypoglycemic medications (Avandia, Diabeta, Glucophage,Glucotrol)
  • methotrexate

Sulfasalazine (Alzulfine) can decrease the effects of digoxin and iron and increase the effects of oral antiocoagulants, hypoglycemics, and methotrexate.

How long do I need to take 5-ASA medications?

5-ASA drugs are prescribed for maintenance treatment. They are designed to prevent flares of your disease. So you will need to take them for many years, even when you are feeling better and having few, if any, symptoms.

Studies have shown that when people stop taking the 5-ASA medications, up to half will have flares after six months.

Lower doses of 5-ASAs can be used if you have been well for many years. But don’t cut back on your own. Any change in dosage should be discussed with your doctor and care team.

5-ASA drugs and Pregnancy

An uncontrolled flare of your disease can be more harmful to the baby than the 5-ASA drugs. 5-ASA drugs do cross the placenta, but studies have not found an increased incidence of fetal abnormalities in women taking them. 5-ASA drugs should be avoided during pregnancy.
Some research has linked Asacol to possible increases in congenital abnormalities, so many doctors now switch their pregnant patients to another 5-ASA drugs.

Mothers who breastfeed can continue to take the mesalaine-based 5-ASA drugs, but their infants should be watched for problems from diarrhea.