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Sulfasalazine

Brand names: Azulfidine, Azulfidine EN-tabs

Sulfasalazine treats ulcerative colitis and rheumatoid arthritis by calming inflammation.

Brand namesAzulfidine, Azulfidine EN-tabs
Type of medicineDMARD and bowel anti-inflammatory
Prescription?Prescription
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

Blood counts and liver tests are checked during treatment.

What it's used for

  • Ulcerative colitis
  • Rheumatoid arthritis
  • Off-label: psoriatic arthritis and ankylosing spondylitis

How to take it

  • Take it after meals with a full glass of water.
  • Swallow delayed-release tablets whole.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Nausea
  • Headache
  • Loss of appetite
  • Orange-yellow urine or skin (harmless)
Call 911A blistering, peeling, or widespread red rash, especially with fever
Call 911Fever, sore throat, or unusual bruising (low blood counts)
Call your provider todayYellow skin or eyes

Warnings

  • Not for people allergic to sulfa drugs or aspirin.
  • It can lower sperm count while taking it.

Other medicines, foods, and alcohol

  • It lowers folic acid absorption.
  • It may change digoxin levels.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Often continued in pregnancy with folic acid. Talk with your provider.

Missed doses, overdose, and storage

If you miss a dose

Take it as soon as you remember, unless it's almost time for your next dose. Then skip the missed dose. Don't take two doses at once.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Conditions it's used for

Sources

Last updated 2026-11-13.