How Aminosalicylates Reduce Autoimmune Inflammation

Aminosalicylates (also called 5-aminosalicylic acids or 5-ASA) are a type of disease-modifying antirheumatic drug (DMARD) given to control inflammation. They have been used to treat inflammatory bowel disease (IBD) and rheumatoid arthritis (RA) for many decades.

These medications are chemically related to aspirin. The drugs in this class of medications contain 5-aminosalicylic acid and other ingredients, which give them the needed anti-inflammatory effect.

This article will discuss what conditions are treated with aminosalicylates, when they may be used, side effects, and how well they work.

What to Know About Aminosalicylates - Illustration by Daniel Fishel

Verywell / Daniel Fishel

What Does 5-ASA Medication Treat?

The 5-ASA medications are used to treat ulcerative colitis, rheumatoid arthritis, and in some specific cases, Crohn’s disease.

Ulcerative colitis is one form of IBD. It causes inflammation of the bowel (colon or large intestine) and rectum, and internal sores called ulcers. The 5-ASA is used to treat the ulcers and inflammation in the colon that is caused by the disease.

Oral 5-ASA drugs are recommended for use in mild or moderate ulcerative colitis by the guidelines outlined by the American College of Gastroenterology (ACG). For proctitis, which is ulcerative colitis in the rectum, 5-ASA is recommended in a form that is given rectally, as an enema. 

In the case of ulcerative colitis that affects the left side of the colon, using both an oral and rectal form of 5-ASA may be recommended.

Rheumatoid arthritis is an autoimmune disease affecting the joints and other tissues. The 5-ASA drug Azulfidine (sulfasalazine) may be used as one of the first medications to get the disease under control. It might be prescribed at the same time as other DMARDs, including Plaquenil (hydroxychloroquine), Arava (leflunomide), or Trexall (methotrexate).

Sulfasalazine might be used to treat mild to moderate Crohn’s disease that is in the colon. Crohn’s disease can affect all parts of the digestive tract, including the small and large intestines. By the ACG guidelines, sulfasalazine is not recommended for use in Crohn’s disease that’s causing inflammation outside of the colon.

Other forms of 5-ASA medications, such as Asacol (mesalamine), are not recommended for use in Crohn’s disease. This is an important difference to understand because other than Azulfidine, the 5-ASA drugs haven’t been shown to be effective to treat Crohn’s disease. Using them could mean a delay in getting Crohn’s disease into remission.

Effect on Inflammation

The 5-ASA medications have an anti-inflammatory effect. They act topically to reduce the inflammation in the colon. 5-ASA works with the good bacteria in the colon to directly affect the tissues of the intestinal lining.

With the drug's action taking place in the colon, it tends to have fewer effects on the rest of the body. There are potential side effects and adverse effects, but they are lessened by the delivery method in the colon.

These drugs are most useful in the mild-to-moderate forms of ulcerative colitis. Other medications might be needed to get the inflammation under control for more severe disease, in which there is frequent diarrhea and deeper ulcers in the colon.

List of 5-ASA Drugs

There are several forms of 5-ASA medications available, including those in the list that follows. They are used for various types of diseases. The delivery method used will be the most likely to affect the part of the body that is having the inflammation.

Colazal (balsalazide disodium): This form of 5-ASA comes in the form of a capsule. It's chemically bonded to an inert ingredient. The bond between the two chemicals breaks down in the colon, releasing the 5-ASA there to act on the tissue of the intestine.  

Azulfidine (sulfasalazine): This type of 5-ASA is the one that has been in use the longest. It contains a component called sulphonamide. Sulphonamide is a type of antibiotic. 

In the colon, enzymes break sulfasalazine down into its component parts. Therefore, it acts on the colon topically. This is why it may be helpful to counter inflammation in the colon caused by ulcerative colitis.

It comes in oral form, either with or without an enteric coating (which prevents it from being absorbed or broken down in the stomach). It is usually taken several times a day.

Asacol, Apriso, Pentasa, Salofalk (mesalamine): The oral form of mesalazine was designed to work when it reaches the intestine. The 5-ASA is inside a component that breaks down in the intestines so that it can act on the inflamed tissue there.

There are delayed-release and extended-release forms of this drug. This fromulation helps the drug travel through the esophagus, stomach, and small intestine before breaking down in the colon to have its effects there.

Mesalamine is also available in enema forms. They are inserted into the rectum and work directly at the site of inflammation, which is the lining of the rectum and/or colon.

Dipentum (olsalazine): This form of the drug contains two molecules of 5-ASA that are chemically bonded together. The bond is broken by the enzymes in the colon, releasing the 5-ASA.

Side Effects

The various 5-ASA medications may have some side effects. These can include abdominal pain and cramping, fever, headache, nausea, loss of appetite, rash, or vomiting. Diarrhea is uncommon, but it is possible and can be challenging for those already experiencing it with their IBD.

When to Try 5-ASA Drugs

The 5-ASA drugs are used at different points in the disease process.

For ulcerative colitis, the 5-ASA drugs are what’s called a first-line therapy. That means that they are used before trying other types of medications.

This is in the case of mild-to-moderate disease, when the oral or rectal formulations 5-ASA medications might be effective in calming inflammation. More severe disease would need to be treated with other types of medications.

In Crohn’s disease, sulfasalazine might be used in mild to moderate disease that affects the colon. For inflammation in the small intestine or other parts of the body, or for severe disease, other drugs are recommended.

In rheumatoid arthritis, sulfasalazine is first-line therapy that might be used along with other drugs. If this combination of medications doesn’t have the desired effect on the inflammation, other treatments might be tried.

Who Shouldn’t Use Them

Before taking a 5-ASA drug, tell your healthcare provider about your history of :

  • Allergy to sulfa medications (for sulfasalazine)
  • Allergy to aspirin (for sulfasalazine)
  • Asthma (constriction and inflammation of the airways)
  • Blood disorders
  • Myocarditis (swelling of the heart muscle)
  • Pericarditis (swelling of the sac around the heart)
  • Liver disease
  • Kidney disease
  • Bowel obstruction
  • Phenylketonuria (a genetic condition in which an amino acid isn't broken down and causes nervous system damage)

Do 5-ASA Drugs Work?

The 5-ASA medications do help for mild to moderate types of inflammation. They are often used as the first medications to manage inflammation. They may be less effective in severe disease or they may stop being effective over time. In these cases, when disease activity picks up again, other medications might be used instead. 


The 5-ASA medications may be used to treat ulcerative colitis, rheumatoid arthritis, or certain cases of Crohn’s disease. There are both oral and topical forms of these drugs available to treat ulcerative colitis. Oral sulfasalazine is prescribed to treat Crohn’s disease in the colon (Crohn’s colitis) and rheumatoid arthritis.

A Word From Verywell

The 5-ASA medications have been in use for decades, so there is lots of evidence to show when they do, and when they don’t, work well on inflammation. Some people can’t take these drugs or are intolerant of them, but that is not common.

There are many more medications available to treat IBD and RA, but the 5-ASA drugs remain some of the first ones prescribed because they can be effective, generally have fewer side effects, and may be inexpensive.

However, it’s important to recognize when these medications aren’t working well to stop inflammation and move on to another type of treatment. 

Frequently Asked Questions

  • How similar are aminosalicylates and NSAIDs?

    Nonsteroidal anti-inflammatory drugs (NSAIDs, such as Advil or Motrin, which are types of ibuprofen, and Aleve, a type of naproxen, as well as their stronger prescription forms), treat pain and inflammation systemically (throughout the body). Aminosalicylates are also anti-inflammatory drugs that work topically (where they are applied). While they have some crossover in their mechanism of action, they are different classes of drugs.

  • Do 5-ASA drugs affect immune function?

    The 5-ASA medications are not considered to be immunosuppressive. Other medications used to treat IBD or rheumatoid arthritis do have an effect on the immune system. However, the 5-ASA medications act directly on the inflammation and not on the immune system.

  • What’s the best aminosalicylate for Crohn’s?

    In the past, various forms of 5-ASA medications were used to treat Crohn’s disease. However, they are now known to be less effective than other medications. In some cases, sulfasalazine might be used to treat mild-to-moderate Crohn’s disease in the large intestine (Crohn’s colitis).

  • How much do aminosalicylates cost?

    Sulfasalazine is an older drug and tends to be more affordable, at $20 a month. Colazal (balsalazide) may be under $100 a month. Oral mesalamine (such as Asacol, Lialda, Delzicol) can range in price from $100 to $300 a month, but some brands (such as Pentasa) may be $1,500 a month or more.

    Mesalamine enemas may cost about $200 a month. Dipentum (osalazine) may be $1,600 a month. There may be patient assistance programs available by contacting the drug manufacturer.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Rubin DT, Ananthakrishnan AN, Siegel CA, Sauer BG, Long MD. ACG Clinical guideline: Ulcerative colitis in adults. Am J Gastroenterol. 2019;114(3):384-413. doi:10.14309/ajg.0000000000000152. 

  2. Singh JA, Saag KG, Bridges SL Jr, et al. 2015 American College of Rheumatology guideline for the treatment of rheumatoid arthritis. Arthritis Rheumatol. 2016;68(1):1-26. doi:10.1002/art.39480. 

  3. Lichtenstein GR, Loftus EV, Isaacs KL, Regueiro MD, Gerson LB, Sands BE. ACG clinical guideline: Management of Crohn’s disease in adults. Am J Gastroenterol. 2018;113(4):481-517. doi:10.1038/ajg.2018.27. 

  4. Sulfonamides. In: LiverTox: Clinical and research information on drug-induced liver injury. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; December 5, 2017.

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.