What is the treatment for colitis, specifically ulcerative colitis?

Treatment for Ulcerative Colitis

First-Line Therapy for Mild-to-Moderate Disease

Start with oral mesalamine 2.4-4.8 g/day combined with topical mesalamine therapy for mild-to-moderate ulcerative colitis, escalating to oral prednisolone 40 mg daily if no response within 2-4 weeks. 1

Disease Location-Specific Approach

For ulcerative proctitis:

• Use mesalamine 1 g suppository once daily as first-line treatment, which delivers medication more effectively to the rectum than foam or enemas and is better tolerated 1, 2
• Combine topical mesalamine with oral mesalamine ≥2.4 g/day for enhanced efficacy, which is more effective than either alone 1

For left-sided colitis:

• Initiate mesalamine enema ≥1 g/day combined with oral mesalamine ≥2.4 g/day, which is more effective than oral or topical therapy alone and superior to topical steroids 3, 1, 2
• Once-daily dosing with mesalamine is as effective as divided doses and improves adherence 3, 4

For extensive colitis:

• Start with aminosalicylate enema 1 g/day combined with oral mesalamine ≥2.4 g/day 3
• Standard dose mesalamine (2-3 grams/day) is preferred over low-dose mesalamine or sulfasalazine 2, 4

Corticosteroid Management for Moderate-to-Severe Disease

Use prednisolone 40 mg daily for moderate-to-severe ulcerative colitis, as 40 mg/day is more effective than 20 mg/day with no additional benefit from higher doses but increased adverse effects. 1

• Taper gradually over 8 weeks according to severity and patient response, as more rapid reduction is associated with early relapse 1
• Escalate to advanced therapy if no adequate response within 2 weeks, if corticosteroid taper is unsuccessful, or to avoid repeated courses 1

Advanced Therapy (Biologics and Small Molecules)

Infliximab and vedolizumab are the preferred first-line biologics in biologic-naïve patients with moderate-to-severe disease. 1, 4

• Infliximab dosing: 5 mg/kg IV at weeks 0,2, and 6, then every 8 weeks for maintenance 5
• Combination therapy (biologic + immunomodulator) is more effective than monotherapy, with azathioprine or mercaptopurine recommended alongside infliximab 1, 4
• For patients who respond then lose response, consider increasing infliximab to 10 mg/kg 5
• Patients who do not respond by week 14 are unlikely to respond with continued dosing and should discontinue 5

Common Pitfall

Do not delay biologic therapy in patients with moderate-to-severe disease who fail corticosteroids within 2 weeks—early escalation prevents complications and improves long-term outcomes 1

Acute Severe Ulcerative Colitis (Hospitalized Patients)

Manage jointly with a gastroenterologist and colorectal surgeon, with daily physical examination for abdominal tenderness and rebound. 2, 4

• Administer IV methylprednisolone 40-60 mg/day (or hydrocortisone 400 mg/day) as first-line treatment 4, 6
• Provide IV fluid and electrolyte replacement, maintain hemoglobin >10 g/dL, and administer subcutaneous heparin to reduce thromboembolism risk 2, 4
• For patients refractory to IV corticosteroids after 3-5 days, use rescue therapy with infliximab or cyclosporine 2, 6
• If medical therapy fails, perform timely colectomy to prevent critical complications 6

Critical Warning

Exclude superimposed bacterial or viral infections before escalating immunosuppression in acute severe colitis 6

Maintenance Therapy

All patients require lifelong maintenance therapy, especially those with left-sided or extensive disease, with 5-ASA doses of ≥2 g/day. 1, 2, 4

• Time spent in remission is longer when maintenance dose is increased from 1.2 to 2.4 g/day, with patients with extensive disease benefiting most 3, 1
• Continuing the induction dosage for an extra 4 weeks prolongs remission and reduces relapse frequency 3, 1
• Patients in remission with biologics and/or immunomodulators after prior failure of 5-ASA may discontinue 5-aminosalicylates 2, 4

Evidence Nuance

While older guidelines from 2006 suggested ≥2 g/day for maintenance 3, the most recent 2025 guidelines from the American Gastroenterological Association confirm this recommendation remains current and evidence-based 1, 2, 4

Treatment Goals and Monitoring

Shift treatment goals from achieving clinical response to achieving remission, assessed biochemically or endoscopically and histologically. 1

• Histologic remission is achieved after induction in up to 45% of patients with topical 5-ASA and 30% with oral formulations 1, 7
• Monitor for response and escalate treatment if symptoms deteriorate, rectal bleeding persists beyond 10-14 days, or sustained relief has not been achieved after 40 days of appropriate 5-ASA therapy 1, 2

Special Considerations

Screen for latent tuberculosis before initiating infliximab, as treatment for latent infection should be initiated prior to use. 5

• Monitor closely for invasive fungal infections (histoplasmosis, coccidioidomycosis) and bacterial infections during and after infliximab treatment 5
• Be aware of increased lymphoma risk, particularly hepatosplenic T-cell lymphoma in adolescent and young adult males receiving TNF blockers with concomitant azathioprine or 6-mercaptopurine 5