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Sulfasalazine

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Sulfasalazine, Azulfidine

  • Contraindications
  1. Significant renal dysfunction
  2. Significant hepatic dysfunction
  3. Bowel Obstruction
  4. Porphyria
  5. Sulfa Allergy
    1. Consider Mesalamine (Asacol, Pentasa) as alternative
    2. Consider slowly tapering to dose if unclear allergy
      1. Start: 250 grams per day
      2. Increase: 250 grams per week
  • Mechanism
  1. 5-Aminosalicylic Acid Derivative which is metabolized into sulfapyridine and Mesalamine by colonic Bacteria
  • Medications
  1. Sulfasalazine (Azulfidine)
    1. Available as 500 mg oral tablets
    2. Total 4 grams is equivalent to 1.6 grams 5-ASA
  2. Enteric-coated Sulfasalazine (Azulfidine EN Tabs)
    1. Available as 500 mg delayed release tablets
    2. Total 4 grams is equivalent to 1.6 grams 5-ASA
    3. Better tolerated than standard Sulfasalazine
  1. General
    1. Increase slowly to lowest effective dose
    2. Co-administer Folic Acid 1 mg/day
    3. Starting Protocol (example in adults)
      1. Start: 500 mg per day
      2. Increase: 500 mg per week up to 2 grams per day
      3. Increase: 3 grams per day after 3 months
      4. Maximum: 4 grams per day (2 grams twice daily) after 6 months
  2. Active Disease (Induction)
    1. Take 500 to 1000 mg orally four times daily (max: 4 to 6 g/day)
  3. Maintenance
    1. Take 500 orally four times daily (max: 2 to 4 g/day)
  1. Avoid in age <2 years
  2. Supplement Folic Acid
  3. Active Disease (Induction) for age 6 years and older
    1. Give 40 to 60 mg/kg/day orally divided 3 to 6 times daily (max: 75 mg/kg/day)
  4. Maintenance for age 6 years and older
    1. Give 30 mg/kg/day orally divided 4 times daily with food
  • Adverse Effects
  1. General
    1. Take Folic Acid 1-2 mg/day
  2. Nausea and other Gastrointestinal Intolerance (30%)
    1. Decreased appetite
    2. Dyspepsia
    3. Nausea or Vomiting
    4. Consider enteric coated Azulfidine EN-tablets (better tolerated)
  3. Neurologic adverse effects
    1. Headache (20%)
    2. Dizziness or Lightheaded (<20%)
  4. Hematologic adverse effects (marrow suppression)
    1. Folate-inhibition Anemia
    2. Hemolytic Anemia
    3. Granulocytopenia and Leukopenia
    4. Thrombocytopenia
  5. Pulmonary
    1. Fibrosing Alveolitis
  6. Skin rash associated with Sulfa Allergy
    1. Requires discontinuing medication immediately
  7. Sexual Function
    1. Oligospermia (Infertility risk)
  8. Renal adverse effects
    1. Urine Discoloration (orange)
      1. May also discolor other body fluids (e.g. tears and Contact Lenses)
    2. Micro-Crystalluria
      1. Risk of Interstitial Nephritis
      2. Avoid Dehydration
      3. Avoid high doses
  • Monitoring
  1. Complete Blood Count (CBC) every 2 to 4 weeks for 3 months, then every 3 to 6 months
  2. Aspartate Aminotransferase (AST, SGOT) at 2 months
  • Drug Interactions
  1. Decreases other drug levels
    1. Folic Acid
    2. Digoxin
    3. Cyclosporine
    4. Serum Iron
  • Safety
  1. Pregnancy Category B
    1. However, Folate supplementation is critical
  2. Unknown safety in Lactation
    1. Case reports of nursing infants with Diarrhea and bloody stools