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Azulfidine EN-tabs

Generic name: sulfasalazine (SUL fa SAL a zeen)
Brand name: Azulfidine, Azulfidine EN-tabs, Sulfazine
Drug class: 5-aminosalicylates, Antirheumatics

Medically reviewed by on Nov 1, 2021. Written by Cerner Multum.

What is Azulfidine EN-tabs?

Azulfidine EN-tabs is used to treat ulcerative colitis (UC), and to decrease the frequency of UC attacks. This medicine will not cure ulcerative colitis, but it can reduce the number of attacks you have.

Azulfidine EN-tabs is also used to treat rheumatoid arthritis in children and adults who have used other arthritis medicines that did not work or have stopped working.

Azulfidine EN-tabs may also be used for purposes not listed in this medication guide.


You should not use Azulfidine EN-tabs if you have porphyria, a blockage in your bladder or intestines, or if you are allergic to sulfa drugs, aspirin, or similar medicines called salicylates.

Before taking this medicine

You should not use Azulfidine EN-tabs if you are allergic to it, or if you have:

  • a blockage in your bladder or intestines;

  • porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system);

  • an allergy to sulfa drugs; or

  • an allergy to aspirin or other salicylates (such as Nuprin Backache Caplet, Kaopectate, KneeRelief, Pamprin Cramp Formula, Pepto-Bismol, Tricosal, Trilisate, and others).

Tell your doctor if you have ever had:

  • frequent infections;

  • asthma;

  • low blood cell counts; or

  • liver or kidney disease.

Tell your doctor if you are pregnant. Taking Azulfidine EN-tabs can make it harder for your body to absorb folic acid, and folic acid helps prevent major birth defects of the baby's brain or spine. You may need to take folic acid supplements if you take this medicine during pregnancy. Follow your doctor's instructions.

Sulfasalazine can pass into breast milk and may cause diarrhea or bloody stools in a nursing baby. Tell your doctor if you are breast-feeding.

Azulfidine EN-tabs is not approved for use by anyone younger than 2 years old.

How should I take Azulfidine EN-tabs?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Take Azulfidine EN-tabs after a meal.

Swallow the tablet whole and do not crush, chew, or break it.

You will need frequent medical tests.

Drink plenty of liquids to keep your kidneys working properly while you are taking Azulfidine EN-tabs.

Azulfidine EN-tabs can affect the results of certain medical tests. Tell any doctor who treats you that you are using this medicine.

Azulfidine EN-tabs may cause your skin or urine to appear orange-yellow in color. Call your doctor if you also have yellowing of your eyes, brown urine, or stomach pain. These may be signs of liver problems.

If you are treating arthritis, do not stop using any of your other arthritis medicines until your doctor tells you to. Azulfidine EN-tabs may not improve your symptoms right away, and you may still need your other medicines for awhile.

Azulfidine EN-tabs is only part of a complete treatment for rheumatoid arthritis that may also include rest and physical therapy. Follow your doctor's instructions very closely.

Store at room temperature away from moisture and heat.

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What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include vomiting, stomach pain, drowsiness, or seizure.

What should I avoid while taking Azulfidine EN-tabs?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Azulfidine EN-tabs side effects

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.

You may get infections more easily, even serious or fatal infections. Call your doctor right away if you have signs of infection such as:

  • fever, chills, sore throat;

  • mouth sores, red or swollen gums;

  • pale skin, easy bruising, unusual bleeding; or

  • chest discomfort, wheezing, dry cough or hack, rapid weight loss.

Also call your doctor at once if you have:

  • fever with headache, rash, and vomiting;

  • a skin rash, no matter how mild;

  • severe nausea or vomiting when you first start taking Azulfidine EN-tabs;

  • little or no urination, urine that looks foamy;

  • puffy eyes, swelling in your ankles or feet, weight gain; or

  • liver problems--loss of appetite, stomach pain (upper right side), dark urine, jaundice (yellowing of the skin or eyes).

Common side effects may include:

  • nausea, vomiting, upset stomach, loss of appetite;

  • headache;

  • rash; or

  • low sperm count in men.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Azulfidine EN-tabs?

Other drugs may affect Azulfidine EN-tabs, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.