Sulfasalazine - Sulphasalazine 💊
⚠️ Patient advice: Report immediately if rash, sore throat, purpura, bruising, bleeding, fever, or infection symptoms develop. These may signal blood dyscrasias or hypersensitivity.
- 🔹 A combination drug of 5-aminosalicylate (5-ASA) linked to sulphapyridine via an azo bond.
- 🧪 The 5-ASA component → local anti-inflammatory effect in the colon.
The sulphapyridine carrier → systemic effects, esp. useful in rheumatoid arthritis.
- 📉 Poor bowel absorption keeps drug concentrated in the gut lumen.
⚙️ Mode of Action
- 🧪 In the colon, gut bacteria split sulfasalazine into:
– 5-ASA → reduces prostaglandins & cytokines, ↓ inflammation in IBD.
– Sulphapyridine → provides immunomodulatory activity in RA.
- 📍 Dual activity makes it useful in both IBD and rheumatology.
🎯 Indications / Dose
- 🤲 Rheumatoid Arthritis: start 500 mg daily → titrate to 2 g/day PO in divided doses over weeks.
- 💥 Acute UC / Crohn’s colitis: 1–2 g PO 6-hourly in active disease → reduce to 500 mg QDS for maintenance.
- 📍 Rectal formulations (distal UC):
– Suppositories: 0.5–1 g BD.
– Enemas: 3 g nocte.
🔄 Interactions
- ⚠️ Use cautiously with other bone marrow suppressants (risk of additive toxicity).
⛔ Contraindications
- 🚫 Severe renal or hepatic impairment.
- 🚫 Acute porphyrias.
- ⚠️ G6PD deficiency (risk of haemolysis).
- ⚠️ Allergy, asthma (higher risk of hypersensitivity reactions).
- 🤰 Can be used in pregnancy, but supplement with folic acid (antifolate activity).
⚠️ Side Effects
- 🍽️ GI: nausea, vomiting, diarrhoea, gallstones.
- 🧑🧑 Male infertility: reversible azoospermia.
- 🤕 Hypersensitivity: rash, Stevens–Johnson syndrome, interstitial nephritis, lupus-like syndrome.
- 🩸 Haematological: agranulocytosis, aplastic anaemia, neutropenia, thrombocytopenia → urgent FBC if unexplained anaemia, infection, or bleeding.
- 🫁 Pulmonary: fibrosing alveolitis, eosinophilia.
- 🧠 Neurological: depression, peripheral neuropathy.
- 🟠 Cosmetic: orange urine & tears (warn contact lens wearers).
📌 Cautions & Monitoring
- 📊 FBC: every 2 weeks for first 12 weeks, then at least monthly until stable.
- 📊 LFTs: monthly for 12 weeks, then periodically.
- ⚠️ Monitor renal function periodically (U&E, creatinine).
- 👀 Advise patients about early warning signs (rash, sore throat, bleeding, bruising).
📚 References
