Sulfasalazine: What is it? How does it work? Uses, Side Effects, Interactions and Warnings

It is a prescription medication that is available as the brand-name drug Azulfidine. It is also available as a generic medicine.

Generic drugs usually cost less. In some cases, they may not be available in all strengths or forms such as the brand.

For what do you use it?

Sulfasalazine is used to reduce inflammation and pain in rheumatoid arthritis (RA), juvenile rheumatoid arthritis (JRA), and ulcerative colitis (UC).

In AR and ARJ, the drug is used to treat people who have not responded to other therapies. It is used to reduce pain and swelling in the joints.

The medication is used to treat inflammation in the intestine and stomach that occurs with UC. It also helps to increase the time between outbreaks or CU attacks.

It can be used alone to treat mild to moderate pain. It can also be used in conjunction with other medications to treat severe UC when other therapies do not work.

This medicine can be used as a supplement in a combination treatment. That means you may need to take it with other drugs.

How does it work?

Sulfasalazine is an anti-inflammatory drug. It is not completely understood how it works. It is thought to affect your immune system and decrease inflammation.

Side effects

The oral sulfasalazine tablet may cause drowsiness. It can also cause other side effects.

The most common side effects:

  • Decreased appetite.
  • Headache.
  • Nausea.
  • Vomiting
  • Upset stomach and pain.
  • Eruption.
  • Itch.
  • Decreased sperm count (only while taking the medication).
  • Dizziness.

Mild effects can go away in a few days or a couple of weeks. Talk to your doctor or pharmacist if they are more serious or if they do not go away.

Serious side effects

If you experience any of these serious side effects, call your doctor immediately. If your symptoms are life threatening or if you think you are experiencing a medical emergency, call 911.

Blood disorder or liver damage. Symptoms include:

  • Sore throat.
  • Fever.
  • Pallor.
  • Purple spots on your skin
  • Yellowing of your skin or the whites of your eyes.

Severe skin disorder. Symptoms include:

  • Symptoms similar to the flu.
  • Red or painful purple rash.

Kidney damage Symptoms include:

  • Difficulty urinating, making less urine or not urinating at all


The oral sulfasalazine tablet may interact with other medications, herbs or vitamins you may be taking. That is why your doctor must administer all your medications carefully.

If you are curious about how this medication might interact with something else you are taking, talk to your doctor or pharmacist.

Note : You can reduce your chances of interactions with other medications by filling all your prescriptions in the same pharmacy. In this way, a pharmacist can verify possible drug interactions.

Examples of medications that can cause interactions with sulfasalazine are listed below.

Folic acid

Folic acid (vitamin B9) is less absorbed by your body when you take sulfasalazine. Your doctor may recommend a folic acid supplement or a higher dose if you are already taking one.


This medication is less absorbed when you take it while taking sulfasalazine. Your doctor will monitor the amount of digoxin you receive and may increase your dose.

Highlights of sulfasalazine

  • The oral sulfasalazine tablet is available as a generic and brand-name drug. Brand: Azulfidine.
  • The tablets come in the form of immediate release and prolonged release.
  • Sulfasalazine is used to treat rheumatoid arthritis, juvenile rheumatoid arthritis, and ulcerative colitis.

Important warnings

Allergy warning: Tell your doctor if you are allergic to sulfasalazine, sulfonamides or salicylates. If you are allergic to these medications, you may have a very serious reaction that could be fatal.

Infection warning: Sulfasalazine may increase the risk of infections by decreasing your body’s immunity. Call your doctor right away if you have signs of an infection, such as fever, sore throat, or paleness. The doctor will check your blood regularly to detect infections.