Mode of action
Exact mechanism unknown but exert local anti-inflammatory action in the bowel wall.
Indications
Ulcerative colitis; acute and remission maintenance; rheumatoid arthritis; Crohn’s disease (limited role in colonic
disease; much less effective than in ulcerative colitis).
Contraindications
Allergy to sulfonamide or salicylate.
Specific considerations
Blood dyscrasias, increased risk of myelosuppression.
Asthma, severe allergy may be exacerbated.
Renal impairment: use with caution; monitor regularly, especially in severe impairment; possible risk of worsening
renal impairment.
Hepatic impairment: use with caution in severe impairment as hepatically cleared.
Surgery: continue treatment throughout perioperative period.
Pregnancy: safe to use; give a folic acid supplement daily (0.5–5 mg); ADEC category A.
Breastfeeding: Safe to use.
Adverse effects
More common with higher doses.
Common: vomiting, reversible male infertility (oligospermia), haemolysis (not usually severe) nausea, rash,
headache, diarrhea.
Infrequent: yellow–orange discolouration of urine or skin interstitial nephritis.
Rare: toxic epidermal necrolysis, fibrosing alveolitis, meningitis, hypersensitivity including serum sickness,
anaphylactoid reactions, arthralgia, itch., blood dyscrasias, pancreatitis (reversible), hepatitis.
Dosage
Ulcerative colitis
Adult: Acute, oral 2–4 g daily in 3–4 doses. Higher doses (up to 8 g daily) are sometimes used but risk of toxicity is
increased. Maintenance, oral 500 mg 4 times daily.
Localised rectal, 1–2 suppositories morning and night after defecation.
Child >2 years: Acute, oral 40–60 mg/kg daily in 3–4 doses. Maintenance, oral 20–30 mg/kg daily in divided doses.
Colonic Crohn’s disease, mild active: Adult, oral 3–6 g daily in divided doses.
Counselling
Take tablets with food to reduce stomach upset.
Practice points
sulfasalazine’s role in Crohn’s disease is limited to active disease in patients with colonic involvement
obtain urinalysis, liver function tests and complete blood examination at baseline and every 2 weeks for the
first 3 months of treatment, then at least every 6 months
soft (hydrogel) lenses may be stained by sulfasalazine use; disposable lenses may still be used
sulfasalazine impairs absorption of folic acid; consider supplementation, especially before and during
pregnancy.
Products
SULFASALAZINE TABS 500 MG (SALAZOPYRIN®)
