Last reviewed 2026-04-20 · How we verify

Azulfidine En-Tabs (SULFASALAZINE)

Azulfidine En-Tabs (SULFASALAZINE) is a small molecule aminosalicylate that targets Flavin reductase (NADPH) to exert its therapeutic effects. Originally developed by PHARMACIA AND UPJOHN, it is now owned by Pfizer and has been FDA-approved since 1950 for the treatment of Juvenile rheumatoid arthritis, Rheumatoid arthritis, and Ulcerative colitis. The drug has a bioavailability of 15% and a half-life of 7.6 hours. Azulfidine En-Tabs is available as a generic medication, with 8 generic manufacturers, and is off-patent. Key safety considerations include its potential for gastrointestinal side effects and interactions with other medications.

At a glance

Approved indications

• Juvenile rheumatoid arthritis
• Rheumatoid arthritis
• Ulcerative colitis

Common side effects

• Nausea
• Dyspepsia
• Rash
• Headache
• Abdominal pain
• Vomiting
• Fever
• Dizziness
• Stomatitis
• Pruritis
• Abnormal liver function tests
• Leukopenia

Drug interactions

• methotrexate
• pralatrexate
• valdecoxib

Key clinical trials

• Venlafaxine as Adjunct Therapy in Rheumatoid Arthritis (PHASE2)
• Sulfasalazine for the Treatment of Primary Sclerosing Cholangitis (PHASE2)
• Recombinant Herpes Zoster Vaccine in Patients With Autoimmune Rheumatic Diseases Under Immunomodulators (PHASE4)
• Validation of Hemoglobin A1c in Patients With Inflammatory Arthritis Treated With Sulfasalazine
• "Effect of Vitamin E (α-Tocopherol) on Clinical Activity and Inflammation in Rheumatoid Arthritis" (PHASE2,PHASE3)
• Analysis of T and B Cell Repertoire Changes in Response to Orencia® (Abatacept) in Rheumatoid Arthritis
• The Effect of Cilostazol on Rheumatoid Arthritis Patients (PHASE2,PHASE3)
• Severe Psoriatic Arthritis - Early intervEntion to Control Disease: the SPEED Trial (PHASE4)

Primary sources

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