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Generic Name

sulfasalazine (SAS) (sul fa SAL a zeen)


Trade Name

Azulfidine EN-tabs


What is sulfasalazine?

This drug was developed in the early 1950’s for the treatment of rheumatoid arthritis for which it is still used. It was the first of a group of drugs that are called 5-aminosalicylates. It is effective against ulcerative colitis and, at times, Crohn’s colitis. It is made up of two drugs which are chemically bonded together, a sulfa drug, sulfadiazine, and mesalamine. It is the latter that is effective against colitis. The bacteria in the colon break the chemical bond between the drugs and so release the active mesalamine in the colon where it can exert its effect. For this reason, it is usually not effective for inflammation in the small bowel.


What is it used for?

The primary use for this drug is ulcerative colitis. Since its action is in the colon, at times, it is tried for Crohn’s colitis. It also is used in collagenous or lymphocytic colitis, rheumatoid arthritis, psoriasis and psoriatic arthritis.


How do I take it?

Follow your physician’s instructions carefully. It is best taken with 8 ounces of water in evenly spaced equal doses. It is recommended that the interval between doses does not exceed 8 hours (even at night). It may be taken after meals or with food to reduce stomach irritation. The regular tablet may be crushed, however, the Azulfidine EN-tab should be swallowed whole. 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, take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and return to your regular schedule. Do not double up on the medicine.


Are there interactions with food or beverages?

The drug may be taken with milk. Use alcohol with caution until the combined effect has been determined. Sulfasalazine can increase the intoxicating effects of alcohol.


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 the following:

  • blood thinners (Coumadin)
  • digoxin (Lanoxin)
  • methotrexate (Rheumatrex)
  • folic acid
  • birth control pills
  • anti-diabetic agents
  • thiazide diuretics
  • phenytoin (Dilantin)


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, the following disorders may be a problem:

  • porphyria
  • severe liver disease (cirrhosis)
  • severe kidney disease
  • blood disorders such as bone marrow failure


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 fever, skin rash or itching. Of course, a person should not take sulfasalazine if there has been a previous reaction to this or any sulfonamide-like drug such as acetazolamide (Diamox), thiazide diuretics (Dyazide, hydrochlorothiazide), sulfonylurea anti-diabetics (Diabinese, Glucotrol, Tolinase, Orinase) or 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. Sulfasalazine is ranked B. Always consult your physician before taking any drug during or when planning pregnancy.


What are the effects on sexual function?

Men may experience a decreased production of sperm and infertility that is reversed with the discontinuation of the drug.


Are there other precautions?

A large volume of water, up to two quarts daily, is required to avoid kidney stones. The drug may cause dizziness, so restrict driving and hazardous activities until the effect has been determined. You may experience sun and light sensitivity so avoid prolonged sun exposure. Sunscreen and sunglasses may be necessary.How long is it safe to take sulfasalazine?

Regular use for 1 to 3 weeks will determine the effectiveness of the drug in controlling colitis symptoms. Long-term use requires physician 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 sulfasalazine, the following are the observed side effects:


  • headahe
  • dizziness
  • indigestion
  • loss of appetite
  • nausea
  • vomiting
  • diarrhea
  • rash
  • orange color to urine (no significance)


  • severe skin reaction
  • joint or muscle pain
  • bloody urine
  • reduced sperm count
  • weakness
  • fever
  • sore throat
  • abnormal bleeding or bruising
  • yellow color to skin or eyes


A physician’s comment…

Patients with mild to moderate ulcerative colitis may do just fine with this drug. It is the least expensive of any of the drugs in this category and can be obtained generically for even less cost. The problem with sulfasalazine is that high doses of the active ingredient, mesalamine, can generally not be reached because gastric upset usually occurs. The newer but more expensive mesalamine drugs, Asacol and Pentasa, can be taken at higher doses without GI upset. However, if 6 to 8 tablets a day of sulfasalazine are effective, then there is nothing cheaper.