What is the initial treatment for colitis?

Initial Treatment for Colitis

For newly diagnosed ulcerative colitis, start with combination therapy of topical mesalamine ≥1 g/day plus oral mesalamine ≥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 mesalamine 1 g suppository once daily as the preferred initial treatment, as it delivers medication more effectively to the rectum than foam or enemas and is better tolerated 1, 2
• Add oral mesalamine ≥2.4 g/day to enhance effectiveness beyond suppository alone 2
• Topical mesalamine is more effective than topical corticosteroids and should be preferred 1, 3

Left-Sided Colitis

• Start with mesalamine enema ≥1 g/day combined with oral mesalamine ≥2.4 g/day 1
• This combination is more effective than oral or topical aminosalicylates alone, or topical steroids alone 1
• Once-daily dosing is as effective as divided doses and may improve adherence 1, 3

Extensive Colitis

• Begin with combination therapy: topical mesalamine 1 g/day plus oral mesalamine ≥2.4 g/day 1, 3
• For mild ileocolonic Crohn's disease, high-dose mesalamine 4 g daily may be sufficient initial therapy 4

Treatment Escalation Strategy

If No Improvement Within 10-14 Days

• Increase oral mesalamine 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 mesalamine (4.8 g/day) compared to 16 days with standard dose (2.4 g/day) 1

If Inadequate Response After 40 Days of Optimized Mesalamine

• 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
• Taper gradually over 8 weeks; more rapid reduction is associated with early relapse 4, 2

Alternative Corticosteroid Option

• Consider budesonide MMX 9 mg/day for left-sided disease as it has fewer systemic side effects than conventional steroids 1, 3
• Budesonide 9 mg daily is appropriate for isolated ileo-caecal Crohn's disease with moderate activity, but marginally less effective than prednisolone 4

Moderate to Severe Disease

• For moderate to severe disease at presentation, oral prednisolone 40 mg daily is appropriate initial therapy 4, 1
• Approximately 50% of patients experience short-term corticosteroid-related adverse events such as acne, edema, sleep and mood disturbance, glucose intolerance, and dyspepsia 1
• Intravenous steroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day) are appropriate for patients with severe disease 4

Critical Monitoring and Safety

Renal Function Monitoring

• Check eGFR before starting mesalamine, after 2-3 months, and then annually 1, 2
• Regular monitoring is essential for patients on long-term 5-ASA therapy 1, 3

Infection Exclusion

• Always exclude infectious causes before attributing symptoms to IBD flare 3
• Concomitant intravenous metronidazole is often advisable with IV steroids, as it may be difficult to distinguish between active disease and septic complications 4

Maintenance Therapy After Remission

• Continue lifelong maintenance therapy with mesalamine 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

Common Pitfalls to Avoid

• Do not start with low-dose mesalamine and escalate—begin at therapeutic doses (≥2.4 g/day oral, ≥1 g/day topical) 1, 2, 5
• Avoid rapid corticosteroid tapers, which are associated with early relapse 4, 2
• Do not use long-term steroids; patients requiring two or more courses in the past year need treatment escalation to thiopurines, anti-TNF therapy, vedolizumab, or tofacitinib 1
• Do not use topical corticosteroids as first-line when topical mesalamine is more effective 1, 3