A prodrug combining sulfapyridine and 5-aminosalicylic acid (5-ASA) linked by an azo bond, used for the treatment of mild-to-moderate ulcerative colitis and rheumatoid arthritis. Colonic bacteria cleave the azo bond, releasing the active 5-ASA moiety locally in the colon, while sulfapyridine is absorbed systemically.
Known hypersensitivity to sulfasalazine, sulfonamides, or salicylates1,2
Intestinal or urinary obstruction
The bottom line
Evidence rating strong. Most-documented uses: induction and maintenance of remission in ulcerative colitis, treatment of rheumatoid arthritis (dmard), anti-inflammatory effect on colonic mucosa. 10 sources indexed (1990–2025), with 2 interaction records on file.
The science
How it works, mechanistically.
Core mechanism
Bacterial azoreductases in the colon cleave sulfasalazine into sulfapyridine and 5-ASA. The 5-ASA component acts locally as an anti-inflammatory agent by inhibiting cyclooxygenase and lipoxygenase pathways, reducing prostaglandin and leukotriene production, and scavenging free radicals. In rheumatoid arthritis, the intact molecule and sulfapyridine component contribute anti-inflammatory and immunomodulatory effects, although the exact mechanism in RA is not fully understood.1,2
Class
Aminosalicylate (IBD/DMARD)
Absorption
Water-soluble; take with food
Dosing
Dosing & protocol.
Common range
UC: 3–4 g/day in divided doses (maintenance: 2 g/day); RA: 2–3 g/day in divided doses (as prescribed by your physician)
Recommended form
Tablet (immediate-release or enteric-coated)
Take with food or immediately after meals to reduce GI side effects; adequate fluid intake recommended; may discolor urine/skin orange-yellow
Depletions
What it depletes.
Nutrients this medication can lower over time, and what to replace.
Folate
Significant
Sulfasalazine impairs folate absorption in the small intestine and can lower folate status during chronic therapy.
Replace MethylfolateMonitor Serum folate or RBC folateOnset Usually after weeks to months
Safety
Full safety detail.
Side effects
Nausea and vomiting
Headache
Anorexia
Skin rash
Oligospermia (reversible)
Hemolytic anemia (in G6PD deficiency)
Hepatotoxicity (rare)
Agranulocytosis (rare)
Contraindications
Known hypersensitivity to sulfasalazine, sulfonamides, or salicylates1,2
Intestinal or urinary obstruction
Porphyria
Severe hepatic or renal impairment
G6PD deficiency (increased risk of hemolytic anemia)
Sulfasalazine can reduce folate absorption and inhibit folate-dependent enzymes. Most people do not develop severe deficiency, but risk rises with long-term therapy, low dietary folate intake, pregnancy, anemia, or other antifolate medicines. Vitamin B9 supplementation helps offset this depletion risk during sulfasalazine therapy.
Recommendation: Ask your prescriber whether you should take daily folate while using sulfasalazine, especially if you are pregnant, planning pregnancy, anemic, or taking another antifolate drug. Do not use folate to ignore new mouth sores, severe fatigue, bruising, or worsening anemia; those symptoms need lab review.
Curcumin has been studied as an add-on to sulfasalazine or mesalamine for ulcerative colitis remission maintenance. In a randomized trial, adding curcumin to standard 5-ASA therapy reduced relapse during the treatment period and improved clinical and endoscopic activity scores. This is an adjunctive anti-inflammatory strategy, not a replacement for sulfasalazine.
Recommendation: If your ulcerative colitis is stable on sulfasalazine, discuss curcumin as an adjunct rather than stopping your prescription. Avoid high-dose curcumin if you have gallbladder disease, are on anticoagulants, or are scheduled for surgery. Track stool frequency, bleeding, and abdominal pain so flares are not missed.
Asthana R, Hamandi B, Brnabic A et al.. Meta-analysis and systematic review on Sulfasalazine/5-ASA use during pregnancy: Impact on neonatal and pregnancy outcomes. Reproductive toxicology (Elmsford, N.Y.). 2025
Steinhart AH, Hemphill D, Greenberg GR. Sulfasalazine and mesalazine for the maintenance therapy of Crohn's disease: a meta-analysis. The American journal of gastroenterology. 1994
Sutherland LR, May GR, Shaffer EA. Sulfasalazine revisited: a meta-analysis of 5-aminosalicylic acid in the treatment of ulcerative colitis. Annals of internal medicine. 1993
Guo D, Tang B, Luo P et al.. A real-world pharmacovigilance study and pharmacological analysis of sulfasalazine based on the FDA adverse event reporting system (FAERS) database. Expert opinion on drug safety. 2025
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