II. Indications
- Inflammatory Bowel Disease (e.g. Ulcerative Colitis)
-
Rheumatoid Arthritis (especially seronegative)
- Second-line agent in combination with Methotrexate and Hydroxychloroquine
- Psoriatic Arthritis
- Arthritis in Reiter's Syndrome
III. Contraindications
- Significant renal dysfunction
- Significant hepatic dysfunction
- Bowel Obstruction
- Porphyria
-
G6PD Deficiency
- Risk of Hemolysis
- Screen for G6PD Deficiency before dosing
-
Sulfa Allergy
- Consider Mesalamine (Asacol, Pentasa) as alternative
- Consider slowly tapering to dose if unclear allergy
- Start: 250 grams per day
- Increase: 250 grams per week
IV. Mechanism
- Derivative of 5-Aminosalicylic Acid (synthetic salicylic acid)
- Prodrug, metabolized into sulfapyridine and Mesalamine by colonic Bacteria
- Ideal location for activation in Inflammatory Bowel Disease (esp. Ulcerative Colitis)
- Active at connective tissues containing elastin (including those affected by Rheumatoid Arthritis)
- Metabolites have antiinflammatory activity via inhibition of cyclooxygenase and Prostaglandin production
V. Medications
VI. Dosing: Rheumatoid Arthritis
- Sulfasalazine (Azulfidine) 500 mg orally twice to three times daily
- Second-line agent for RA in combination with Methotrexate and Hydroxychloroquine
VII. Dosing: Ulcerative Colitis in Adults
-
General
- Increase slowly to lowest effective dose
- Co-administer Folic Acid 1 mg/day
- Starting Protocol (example in adults)
- Start: 500 mg per day
- Increase: 500 mg per week up to 2 grams per day
- Increase: 3 grams per day after 3 months
- Maximum: 4 grams per day (2 grams twice daily) after 6 months
- Active Disease (Induction)
- Take 500 to 1000 mg orally four times daily (max: 4 to 6 g/day)
- Maintenance
- Take 500 orally four times daily (max: 2 to 4 g/day)
VIII. Dosing: Ulcerative Colitis in Children
- Avoid in age <2 years
- Supplement Folic Acid
- Active Disease (Induction) for age 6 years and older
- Give 40 to 60 mg/kg/day orally divided 3 to 6 times daily (max: 75 mg/kg/day)
- Maintenance for age 6 years and older
- Give 30 mg/kg/day orally divided 4 times daily with food
IX. Adverse Effects
-
General
- Take Folic Acid 1-2 mg/day
- Nausea and other Gastrointestinal Intolerance (30%)
- Neurologic adverse effects
- Headache (20%)
- Dizziness or Lightheaded (<20%)
- Hematologic adverse effects (marrow suppression)
- Pulmonary
- Fibrosing Alveolitis
- Skin rash associated with Sulfa Allergy
- Requires discontinuing medication immediately
- Sexual Function
- Oligospermia (Infertility risk)
- Renal adverse effects
- Urine Discoloration (orange)
- May also discolor other body fluids (e.g. tears and Contact Lenses)
- Micro-Crystalluria
- Risk of Interstitial Nephritis
- Avoid Dehydration
- Avoid high doses
- Urine Discoloration (orange)
X. Drug Interactions
- Decreases other drug levels
XI. Safety
- Pregnancy Category B
- However, Folate supplementation is critical
- Unknown safety in Lactation
- Case reports of nursing infants with Diarrhea and bloody stools
- Monitoring
- Complete Blood Count (CBC) every 2 to 4 weeks for 3 months, then every 3 to 6 months
- Aspartate Aminotransferase (AST, SGOT) at 2 months
XII. Resources
- Sulfasalazine Tablets (DailyMed)
XIII. References
- Hamilton (2020) Tarascon Pocket Pharmacopoeia
- (2022) Treatment of Mild to Moderate Ulcerative Colitis, Presc Lett, #350406
- (2023) Drugs for Inflammatory Bowel Disease, Med Lett Drug Ther 65: 105-12
- Adams (2013) Am Fam Physician 87(10): 699-705 [PubMed]
- Adams (2022) Am Fam Physician 105(4): 406-11 [PubMed]
- Kornbluth (2010) Am J Gastroenterol 105(3): 501-23 [PubMed]
- Matteson (2000) Mayo Clin Proc 75:669-74 [PubMed]
- Pincus (1999) Clin Rheumatol 17(6 Suppl 18):S2-S124 [PubMed]
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