Mechanism of Action
- Active component is 5-aminosalicylic acide (5-ASA, or mesalazine)
- Other forms include
- Sulfasalazine- older; combination of 5-ASA and sulfapyridine (which acts as a carrier although causes side effects)
- Balsalazide and Olsalazine
- Other forms include
- Mechanism of action not fully understood
- Thought to ‘scavenge’ free oxygen radicals locally, and blocks production of prostaglandins and chemotaxis of leukotrienes (immune system modulation)
Indications
- Mainly used in patients with Ulcerative colitis. Also used, but to a lesser degree, in patients with Crohn’s disease (mainly ileocaecal disease).
- Topically used for active proctitis
- Can be used systemically if the patient has a poor response to topical treatment
Cautions/Contraindications
- MONITOR RENAL FUNCTION before, 3 months into and annually during treatment
- Avoid in CKD 4/5 if possible (eGFR<20)
- Avoid in severe liver disease
- Avoid if allergic
Side effects
- Blood disorders (dyscrasia)- quite rare but serious
- Any patient should report any bleeding, bruising, purpura, sore throat, fever, malaise etc
- Stop immediately if thought to be dyscrasia (perform FBC)
- Lupus like syndrome
- Other side effects include:
- Diarrhoea, nausea, vomiting, abdominal pain, exacerbation of symptoms of colitis, headache, allergy
- Rarer effects include: acute pancreatitis, hepatitis, myocarditis/pericarditis; Lung disorder (eosinophilia/fibrosing alveolitis); peripheral neuropathy, myalgia, arthralgia
- Renal dysfunction (interstitial nephritis, nephrotic syndrome)
- Skin reactions (lupus-like syndrome (malar rash); rarely Stevens-Johnson syndrome); alopecia