What is the initial treatment for colitis?

Initial Treatment for Colitis

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

Treatment Algorithm Based on Disease Location and Severity

Ulcerative Proctitis (Rectal Disease Only)

• First-line: Mesalamine 1 g suppository once daily 1, 2
• Suppositories deliver medication more effectively to the rectum than foam or enemas and are better tolerated 1
• Topical mesalamine is more effective than topical corticosteroids 1, 2
• Escalation: Add oral mesalamine ≥2.4 g/day if suppository alone is insufficient, as combination therapy is more effective than either alone 1, 2

Left-Sided Colitis

• First-line: Mesalamine enema ≥1 g/day combined with oral mesalamine ≥2.4 g/day 1, 2
• Once-daily dosing is as effective as divided doses and improves adherence 1, 2
• This combination is more effective than oral mesalamine alone, topical mesalamine alone, or topical steroids 1, 2
• Escalation if no improvement in 10-14 days: Increase oral mesalamine to 4.8 g/day 2
• If inadequate response after 40 days: Add oral prednisolone 40 mg daily, tapered over 6-8 weeks 2, 3
• Alternative to prednisolone: Budesonide MMX 9 mg/day for left-sided disease has fewer systemic side effects 1, 2

Extensive Colitis

• First-line: Mesalamine enema 1 g/day combined with oral mesalamine ≥2.4 g/day 1
• For moderate to severe activity or mesalamine failure: Prednisolone 40 mg daily, tapered gradually over 8 weeks 1, 4
• Rapid tapering increases early relapse rates—avoid reducing steroids faster than 8 weeks 4, 1
• Severe extensive colitis: Requires hospital admission for intravenous steroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day), IV fluids, electrolyte replacement, and blood transfusion to maintain hemoglobin >10 g/dL 4

Severe Ulcerative Colitis (Any Location)

• Immediate hospitalization required 4, 3
• Joint management by gastroenterologist and colorectal surgeon 4, 3
• Intravenous steroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day) 4
• IV fluid and electrolyte replacement 4
• Subcutaneous heparin to reduce thromboembolism risk 4
• Inform patients of 25-30% chance of needing colectomy 4, 3

Crohn's Disease Treatment (When Colitis is Crohn's-Related)

Mild Ileal/Ileocolonic Crohn's Disease

• First-line: High-dose mesalamine 4 g/day 4, 1
• Mesalamine has limited efficacy in Crohn's disease compared to ulcerative colitis—only appropriate for mild disease 1

Moderate to Severe Crohn's Disease

• First-line: Oral prednisolone 40 mg daily, tapered over 8 weeks 4, 1
• Alternative for isolated ileo-caecal disease: Budesonide 9 mg daily (marginally less effective than prednisolone) 4
• Severe disease: IV steroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day) with concomitant IV metronidazole to distinguish active disease from septic complications 4

Crohn's Colitis

• Sulphasalazine 4 g daily is effective but not first-line due to high side effect incidence 4
• Metronidazole 10-20 mg/kg/day has a role in selected patients with colonic disease but is not first-line 4
• Topical mesalamine may be effective in left-sided colonic Crohn's disease of mild to moderate activity 4

Critical Pitfalls to Avoid

Do not start with oral mesalamine alone for ulcerative colitis—combination topical plus oral therapy is significantly more effective than either alone 1, 2, 3

Do not use low-dose mesalamine—start with at least 2.4 g/day oral (or 4.8 g/day for faster response), as higher doses are more effective 2, 5, 6

Do not taper steroids rapidly—reduce gradually over 8 weeks to prevent early relapse 4, 1

Do not assume all colitis is ulcerative colitis—always exclude infectious causes before attributing symptoms to inflammatory bowel disease 3

Do not rely on mesalamine for moderate-to-severe Crohn's disease—corticosteroids are required earlier in the treatment algorithm for Crohn's compared to ulcerative colitis 1

Do not overlook alternative explanations in Crohn's disease—persistent symptoms may be due to bacterial overgrowth, bile salt malabsorption, or fibrotic strictures rather than active inflammation 4, 1

Maintenance Therapy After Remission

• Lifelong maintenance therapy with aminosalicylates is generally recommended, especially for left-sided or extensive disease 4, 2, 3
• Continue mesalamine after achieving remission to prevent relapse 2, 3
• Monitor renal function (eGFR) before starting, after 2-3 months, then annually for patients on long-term 5-ASA therapy 2, 5