What is the initial treatment for colitis?

Initial Treatment for Colitis

For newly diagnosed ulcerative colitis, start with combination therapy of topical mesalazine ≥1 g/day plus oral mesalazine ≥2.4 g/day, which is more effective than either treatment alone for controlling inflammation and symptoms. 1, 2, 3

Treatment Algorithm Based on Disease Location

Proctitis (Rectal Disease Only)

• Use mesalazine 1 g suppository once daily as first-line therapy, as suppositories deliver medication more effectively to the rectum than foam or enemas and are better tolerated 1, 2
• Add oral mesalazine ≥2.4 g/day to enhance effectiveness beyond suppository alone 2
• Topical mesalazine is superior to topical corticosteroids and should be preferred 1, 3

Left-Sided Colitis

• Start with mesalazine enema ≥1 g/day combined with oral mesalazine ≥2.4 g/day 1
• This combination is more effective than oral or topical aminosalicylates alone, or topical steroids alone 1

Extensive Colitis

• Begin with combination therapy: topical mesalazine ≥1 g/day plus oral mesalazine ≥2.4 g/day 1, 3
• Once-daily dosing is as effective as divided doses and may improve adherence 1, 3

Treatment Escalation Strategy

If No Improvement Within 10-14 Days

• Increase oral mesalazine dose to 4.8 g/day 1, 2
• Continue treatment for up to 40 days before determining failure, as sustained remission may take time 1, 2
• The median time to cessation of rectal bleeding is approximately 9 days with high-dose mesalazine (4.8 g/day) compared to 16 days with standard dose (2.4 g/day) 1

If Inadequate Response After 40 Days of Optimized Mesalazine

• Add oral prednisolone 40 mg daily with tapering over 6-8 weeks 1, 2, 3
• Single daily dosing of prednisolone is as effective as split-dosing and causes less adrenal suppression 1
• Avoid rapid corticosteroid tapers as this is associated with early relapse 4, 2

Alternative to Conventional Steroids

• Consider budesonide MMX 9 mg/day for left-sided disease, as it has fewer systemic side effects than conventional steroids 1, 3

Crohn's Colitis Considerations

For Crohn's disease affecting the colon, the approach differs:

• High-dose mesalazine (4 g daily) may be sufficient for mild ileocolonic Crohn's disease 4
• For moderate to severe Crohn's colitis, oral prednisolone 40 mg daily is appropriate, reduced gradually over 8 weeks 4
• Sulphasalazine 4 g daily is effective for active colonic Crohn's disease but cannot be recommended as first-line therapy due to high incidence of side effects 4
• Metronidazole 10-20 mg/kg/day has a role in selected patients with colonic disease but is not first-line therapy 4

Critical Safety Monitoring

• Monitor renal function with eGFR before starting mesalazine, after 2-3 months, and then annually 1, 2, 3
• Approximately 50% of patients experience short-term corticosteroid-related adverse events such as acne, edema, sleep and mood disturbance, glucose intolerance, and dyspepsia 1
• Long-term steroid use should be avoided due to significant side effects 1, 3

Maintenance After Remission

• Continue lifelong maintenance therapy with mesalazine to prevent relapse, especially for those with left-sided or extensive disease 1, 2, 3
• Maintenance therapy may reduce the risk of colorectal cancer 2

Important Pitfalls to Avoid

• Always exclude infectious causes before attributing symptoms to inflammatory bowel disease flare 3
• Do not use mesalazine monotherapy when combination therapy is indicated—combination is consistently more effective 1, 3, 5
• Patients who do not respond to 8 weeks of oral 5-ASA may still enter clinical remission after a further 8 weeks of high-dose (4.8 g) therapy 1
• For severe colitis requiring hospitalization, intravenous steroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day) are appropriate, with joint management by gastroenterology and colorectal surgery 4, 3