1.5.1 Aminosalicylates

For guidance on the management of inflammatory bowel disease (IBD) see Inflammatory Bowel Disease.

Aminosalicylates may cause blood dyscrasias and patients should be told to report any unexplained bleeding, bruising, purpura, sore throat, fever or malaise that occurs during treatment. The BNF recommends a blood count should be performed and the drug stopped immediately if there is suspicion of a blood dyscrasia.

All aminosalicylates are classified as 'Specialist' drugs to reflect the need for specialist input but continuation supplies may be prescribed in primary care.


The BNF states that there is no evidence to show that any one oral preparation of mesalazine is more effective than another; however, the release characteristics of oral mesalazine preparations may vary.

  • Pentasa® granules and tablets continuously release mesalazine throughout the gastrointestinal tract.
  • Octasa® tablets and Salofalk® granules release mesalazine from the terminal ileum to the distal colon.

The choice of topical formulation should reflect the current disease activity, area of the gastrointestinal tract affected, patient preference including ease of insertion or retention of enemas and adherence, which may also influence the dosing frequency and cost.

  • Suppositories are indicated for disease to the rectosigmoid junction; they deliver the drug more effectively to the rectum than enemas. Foam enemas usually treat up to the proximal sigmoid colon; liquid enemas can deliver medication as proximal as the splenic flexure.
  • Foam and liquid enemas appear to be equally effective for proximal ulcerative colitis; foam enemas may be easier to administer and retention is more comfortable.
  • Suppositories are usually better tolerated than enemas.

If it is necessary to switch a patient to a different brand of mesalazine, the patient should be advised to report any changes in symptoms.

Mesalazine intolerance occurs in up to 15% of patients, symptoms include diarrhoea, headache, nausea, thrombocytopenia and rash. Acute intolerance occurs in 3% of patients and may mimic an acute flare with bloody diarrhoea.

Patients need to remain well hydrated whilst taking mesalazine. If a patient develops dehydration, normal electrolyte levels and fluid balance should be restored as soon as possible.

Mesalazine-induced renal toxicity should be considered if renal function deteriorates during treatment. Renal impairment (including interstitial nephritis) is rare and idiosyncratic; it may be related to disease severity rather than dose or type of mesalazine. Mesalazine is contra-indicated in severe renal impairment (eGFR<20mL/minute/1.73m 2) and should be used with caution in less severe impairment. Renal function should be monitored three monthly for the first year and annually thereafter (more frequently in renal impairment) as per BNF.

Mesalazine Summary of Product Characteristics (SPCs) recommend blood tests (differential blood count, liver function parameters such as ALT or AST; serum creatinine) and urinary status (dip sticks) should be determined prior to and during treatment, at the discretion of the treating physician. As a guideline, follow-up tests are recommended 14 days after commencement of treatment and then every 4 weeks for 8-12 weeks. If the findings are normal, follow-up tests should be carried out every three months. If additional signs appear, these tests should be performed immediately. Local specialists will advise on monitoring requirements for individual patients.



  • Tablets modified-release 400mg, 800mg (£37.68 = 2.4g daily, 800mg tablets)

Indications and dose

  • Treatment of mild to moderate ulcerative colitis, acute attack: 2.4g once daily, alternatively 2.4–4.8g daily in divided doses, dose over 2.4g daily in divided doses only
  • Maintenance of remission of ulcerative colitis and Crohn's ileo-colitis: 1.2–2.4g once daily, alternatively daily in divided doses


  • Tablets modified-release 500mg, 1g (£34.43 = 2g daily)
  • Prolonged release granules 1g, 2g, 4g sachets (£34.43 = 2g daily)
  • Retention enema (liquid) 1g/100mL (£17.73 = 7 enemas) (existing patients only)
  • Suppositories 1g (£40.01 = 1g daily) (existing patients only)

Dose and Indications

  • Pentasa® tablets and granules:
    • Treatment of mild to moderate ulcerative colitis, acute attack: up to 4g daily either as a single dose or in 2–3 divided doses (tablets), or 2-4 divided doses (granules).
    • Maintenance of remission of ulcerative colitis: 2g once daily
  • Pentasa® liquid enema (existing patients only):
    • Treatment of acute attack of mild to moderate ulcerative colitis or maintenance of remission: 1g administered once daily at bedtime
  • Pentasa® suppositories (existing patients only):
    • Treatment of acute attack, ulcerative proctitis: 1g administered daily for 2–4 weeks.
    • Maintenance, ulcerative proctitis: 1g administered daily


  • Gastro-resistant prolonged-release granules 500mg, 1g, 1.5g, 3g (£24.14= 500mg 3 times a day)
  • Retention enema (foam) 1g (£30.17 = 14 dose aerosol + applicators)
  • Retention enema (liquid) 2g/59mL (£29.92 = 7 enemas)
  • Suppositories 500mg, 1g (£29.62= 30 x 1g suppositories)

Dose and Indications

  • Salofalk® granules:
    • Treatment of acute attack of ulcerative colitis: 1.5–3 g once daily, or alternatively 0.5–1 g three times a day
    • Maintenance of remission of ulcerative colitis: 500mg three times daily. Patients known to be at increased risk of relapse or have difficulties with adherence the maintenance dosing schedule may be adapted to 3g given as a single daily dose
  • Salofalk® foam enema:
    • Treatment of mild ulcerative colitis affecting sigmoid colon and rectum: 2g administered once daily at bedtime, alternatively 2g administered daily in 2 divided doses.
    • Salofalk® foam enema is not licensed for use in maintenance of remission
  • Salofalk® liquid enema:
    • Treatment of acute attack of mild to moderate ulcerative colitis or maintenance of remission: 2g administered once daily at bedtime
  • Salofalk® suppositories:
    • Treatment of acute attack of mild to moderate ulcerative colitis affecting the rectum, sigmoid colon and descending colon: 500mg – 1g 2–3 times a day, adjusted according to response.
    • Salofalk® suppositories are unlicensed for the maintenance of remission but use in practice is recognised


  • Tablets EC 500mg (£8.43 = 500mg four times a day)



  1. Refer to individual shared care guidelines for use in Gastroenterology and Rheumatology conditions


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