Dosing & Uses
Dosage Forms & Strengths
tablet
- 500mg
tablet, enteric coated (delayed release)
- 500mg
Ulcerative Colitis
Mild to moderate cases, adjunctive therapy in severe cases, and prolongation of remission
3-4 g/day PO divided TID after meals; may start 1-2 g Day; >4g/day can increase risk of toxicity
Maintenance: 2 g/day in divided doses at <8 hr intervals when endoscopic exam confirms improvement
Dosing modifications
- Reduce dose by 50% and gradually increase to desired dose over several days; stop therapy for 5-7 days if GI intolerance persists and reintroduce at lower daily dose
Rheumatoid Arthritis
Indicated in inadequate response or intolerance to salicylates or other NSAIDs
Delayed release: 0.5-1 g/day PO divided BID; increase weekly to maintenance dose of 2 g/day PO divided BID; if response inadequate, may increase to 3 g/day after administering for 12 weeks
Crohn Disease (Off-label)
3-6 g/day PO in divided doses for up to 16 wks
Administration
Take after meals
Administer in equally divided doses
Dosage Forms & Strengths
tablet
- 500mg
tablet, enteric coated (delayed release)
- 500 mg
Ulcerative Colitis
Mild to moderate cases, adjunctive therapy in severe cases, and prolongation of remission
<6 years old: Safety and efficacy not established
6 years or older
- Initial: 40-60 mg/kg/day PO divided q4-8hr after meals
- Maintenance: 30 mg/kg/day PO divided q6hr after meals
Juvenile Rheumatoid Arthritis
Polyarticular course with inadequate response to salicylates or other NSAIDs
<6 years old: Safety and efficacy not established
6 years or older: Gradually titrate at weekly intervals up to 30-50 mg/kg/day PO divided BID after meals; not to exceed 2 g/day
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Adverse Effects
>10%
Anorexia (~33%)
Headache (~33%)
Nausea (~33%)
Vomiting (~33%)
Gastric distress (~33%)
Apparently reversible oligospermia (~33%)
<1%
Skin rash
Pruritus
Urticaria
Fever
Heinz body anemia
Hemolytic anemia
Cyanosis
Postmarketing Reports
Blood dyscrasias: Pseudomononucleosis
Cardiac disorders: Myocarditis
Hepatobiliary disorders: reports of hepatotoxicity, including elevated liver function tests (SGOT/AST, SGPT/ALT, GGT, LDH, alkaline phosphatase, bilirubin), jaundice, cholestatic jaundice, cirrhosis, hepatitis cholestatic, cholestasis and possible hepatocellular damage including liver necrosis and liver failure; some of these cases were fatal; 1 case of Kawasaki-like syndrome
Immune system disorders: Anaphylaxis
Metabolism and nutrition system disorders: Folate deficiency
Renal and urinary disorders: Nephrolithiasis
Respiratory, thoracic and mediastinal disorders: Oropharyngeal pain
Skin and subcutaneous tissue disorders: Angioedema, purpura
Vascular disorders: Pallor
Warnings
Contraindications
Hypersensitivity to sulfasalazine or its metabolites, to sulfonamides, or to salicylates
Intestinal or urinary tract obstruction
Porphyria
Cautions
Serious skin reactions, some of them fatal, including exfoliative dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis; discontinue at first appearance of skin rash, mucosal lesions, or any other sign of hypersensitivity
Severe hypersensitivity reported; may include internal organ involvement, such as hepatitis, nephritis, myocarditis, mononucleosis-like syndrome (ie, pseudomononucleosis), hematological abnormalities (including hematophagic histiocytosis), and/or pneumonitis including eosinophilic infiltration; if signs or symptoms are present, the patient should be evaluated immediately; Sulfasalazine drug should be discontinued if an alternative etiology for signs or symptoms cannot be established
Administer tablets with caution to patients with severe allergy or bronchial asthma; adequate fluid intake must be maintained in order to prevent crystalluria and stone formation; patients with glucose-6 phosphate dehydrogenase deficiency should be observed closely for signs of hemolytic anemia; reaction is frequently dose-related; if toxic or hypersensitivity reactions occur, the drug should be discontinued immediately
Oligospermia and infertility reported; however, withdrawal of drug appears to reverse these effects
Infections
- Blood dyscrasias; serious infections reported, including fatal sepsis and pneumonia
- Some infections were associated with agranulocytosis, neutropenia, or myelosuppression; discontinue therapy if patient develops a serious infection
- Closely monitor patients for the development of signs and symptoms of infection during and after treatment
- Frequently perform complete blood counts, as well as urinalysis with careful microscopic examination; discontinue treatment while awaiting results of blood tests;
Pregnancy & Lactation
Pregnancy category: B; D if used for prolonged periods or near term; increased potential for kernicterus in the newborn
Oral sulfasalazine inhibits the absorption and metabolism of folic acid which may interfere with folic acid supplementation and protection from neural tube defects
Lactation: Excreted into human breast milk; caution with breastfeeding, some reports of bloody stools or diarrhea in human milk fed infants of mothers taking sulfasalazine
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Sulfasalazine is a prodrug that is metabolized to its active components, sulfapyridine and 5-aminosalicylic acid (5-ASA; mesalamine); beneficial effects are predominantly from the anti-inflammatory properties of 5-ASA, which inhibits leukotriene synthesis and lipoxygenase
Absorption
Bioavailability: <15% of parent drug; 60% (sulfapyridine); 10-30% (5-ASA)
Peak plasma time: 6 hr; 10 hr (sulfapyridine and 5-ASA)
Peak plasma concentration: 6 mcg/mL
Distribution
Protein bound: >99% to albumin; 70% (sulfapyridine)
Vd: 7.5 L
Metabolism
Approximately 90% of sulfasalazine is converted by colon bacteria into its active components, sulfapyridine and mesalamine
Elimination
Half-life: 10.4-14.8 hr (sulfapyridine)
Renal clearance: 37%
Excretion: Urine (systematically absorbed sulfapyridine and 5-ASA); feces (majority of 5-ASA)
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Formulary
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