Last reviewed 2026-04-20 · How we verify

Azulfidine En-Tabs (Sulfasalazine)

Anti-inflammatory and immunomodulatory properties with affinity for connective tissue and high concentration in serous fluids.

Sulfasalazine is a sulfonamide indicated for mild to moderate ulcerative colitis and remission maintenance. The drug exhibits low parent compound bioavailability (<15%) but is metabolized to active metabolites with higher intestinal absorption. Key contraindications include obstruction, porphyria, and hypersensitivity to sulfonamides or salicylates. Clinical efficacy primarily derives from the 5-ASA metabolite's anti-inflammatory action in the colon.

At a glance

Mechanism of action

The mode of action of sulfasalazine or its metabolites, 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP), may be related to anti-inflammatory and/or immunomodulatory properties observed in animal and in vitro models. The drug demonstrates affinity for connective tissue and reaches relatively high concentrations in serous fluids, liver, and intestinal walls as demonstrated in autoradiographic studies in animals. In ulcerative colitis, clinical studies utilizing rectal administration of SSZ, SP, and 5-ASA have indicated that the major therapeutic action may reside in the 5-ASA moiety.

Approved indications

• Juvenile rheumatoid arthritis
• Rheumatoid arthritis
• Ulcerative colitis

Common side effects

• Nausea
• Liver function test abnormalities
• Headache
• Diarrhoea
• Infection

Drug interactions

• methotrexate
• pralatrexate
• valdecoxib

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Azulfidine En-Tabs CI brief — competitive landscape report
• Azulfidine En-Tabs updates RSS · CI watch RSS
• Pfizer portfolio CI