What is the recommended treatment regimen for colitis?

Treatment for Colitis

For ulcerative colitis, treatment depends on disease extent and severity: mild-to-moderate extensive disease should be treated with standard-dose oral mesalamine (2-3 grams/day) combined with rectal mesalamine; distal disease responds best to topical mesalamine suppositories or enemas; and patients failing optimized 5-ASA therapy require escalation to oral prednisolone 40 mg daily or advanced therapies (biologics/JAK inhibitors). 1, 2, 3

Disease Extent and Severity Assessment

Treatment selection hinges on two critical factors:

Disease Location:

• Proctitis (rectum only): Topical therapy is first-line
• Proctosigmoiditis (up to sigmoid-descending junction): Topical ± oral therapy
• Left-sided or extensive colitis: Combination oral and topical therapy
• Severe colitis (meeting Truelove-Witts criteria): Hospitalization required

Disease Severity:

• Mild-moderate: Outpatient management with 5-ASA agents
• Moderate-severe or 5-ASA refractory: Advanced therapies
• Severe/fulminant: Intravenous steroids with surgical consultation

Mild-to-Moderate Ulcerative Colitis

Extensive or Left-Sided Disease

First-line therapy combines oral and rectal mesalamine 1:

• Oral mesalamine 2-3 grams/day (standard dose) OR diazo-bonded 5-ASA (olsalazine 1.5-3 g/day or balsalazide 6.75 g/day)
• Add rectal mesalamine 1 gram daily as enema for left-sided disease
• Once-daily dosing is as effective as divided doses and improves compliance 1

If suboptimal response after 2-4 weeks:

• Escalate to high-dose mesalamine (>3 grams/day) with rectal mesalamine 1
• Consider early escalation in patients with moderate symptoms

If inadequate response to optimized 5-ASA:

• Oral prednisolone 40 mg daily 4, 3
• Taper gradually over 8 weeks based on response (rapid reduction increases relapse risk) 4
• Alternative: Budesonide MMX (though less preferred than prednisolone) 1

Distal Disease (Proctosigmoiditis/Proctitis)

Proctitis (rectum only):

• Mesalamine suppositories 1 gram daily - this is the strongest recommendation 1
• If intolerant or refractory: rectal corticosteroid suppositories 1

Proctosigmoiditis:

• Mesalamine enemas 1 gram daily (reaches splenic flexure) 1, 4
• Preferred over rectal corticosteroids due to superior efficacy 1
• Can combine with oral mesalamine, though topical alone may suffice 4

Important caveat: Patients prioritizing convenience over maximal efficacy may choose oral mesalamine alone, though this is less effective 1

Moderate-to-Severe Ulcerative Colitis

Corticosteroid-Refractory or Dependent Disease

Advanced therapies are indicated when:

• No adequate response to oral corticosteroids within 2 weeks 3
• Corticosteroid taper unsuccessful
• Need to avoid repeated corticosteroid courses
• Corticosteroid-dependent disease 2

Recommended advanced therapies (strong recommendation) 2:

• TNF antagonists: Infliximab, golimumab (adalimumab is conditional recommendation)
• Anti-integrin: Vedolizumab
• IL-12/23 inhibitor: Ustekinumab
• IL-23 inhibitors: Risankizumab, guselkumab, mirikizumab (conditional)
• JAK inhibitors: Tofacitinib, upadacitinib (filgotinib conditional)
  • FDA restriction: Use only after TNF antagonist failure/intolerance in the US 2
  • EMA caution: Avoid as first-line in patients ≥65 years, smokers, cardiovascular disease history, cancer history
• S1P receptor modulators: Ozanimod, etrasimod

Combination therapy considerations:

• Combine TNF antagonists with immunomodulators (azathioprine 1.5-2.5 mg/kg/day or mercaptopurine 0.75-1.5 mg/kg/day) for improved efficacy 2
• No recommendation for combining non-TNF biologics with immunomodulators 2

Severe Ulcerative Colitis (Hospitalized)

Immediate management 4:

• Intravenous corticosteroids: Hydrocortisone 400 mg/day OR methylprednisolone 60 mg/day
• Joint gastroenterology-surgical management from admission 4
• Inform patients of 25-30% colectomy risk 4

Supportive care:

• IV fluid/electrolyte replacement
• Blood transfusion to maintain hemoglobin >10 g/dL 4
• Subcutaneous heparin for thromboembolism prophylaxis 4
• Nutritional support if malnourished 4

Monitoring:

• Daily physical examination for peritoneal signs
• Vital signs 4 times daily
• Stool frequency chart
• CBC, CRP, electrolytes, albumin every 24-48 hours 4
• Daily abdominal X-ray if colonic dilatation (>5.5 cm transverse colon) 4

Rescue therapy if no response to IV steroids:

• Infliximab 5 mg/kg
• Tacrolimus (alternative to infliximab)
• Cyclosporine (less commonly used)
• Colectomy if medical rescue fails

Maintenance Therapy

Lifelong maintenance is recommended for most patients, especially those with left-sided/extensive disease or distal disease with >1 relapse/year 4:

• Aminosalicylates (mesalamine, olsalazine, balsalazide) - first-line 4
• Azathioprine or mercaptopurine - for steroid-dependent disease or as steroid-sparing agents 4
• Continue the advanced therapy that induced remission 2, 3
• Do NOT use corticosteroids for maintenance 3

De-escalation considerations:

• Stop 5-ASA once escalated to immunomodulators/advanced therapies 2
• Do NOT withdraw TNF antagonists in patients achieving corticosteroid-free remission on combination therapy 2
• Discontinuation may be reasonable for distal disease in remission >2 years if patient averse to medication 4

Crohn's Colitis

For Crohn's disease affecting the colon 4:

Mild ileocolonic/colonic disease:

• High-dose mesalazine 4 g/daily may suffice 4
• Topical mesalazine for left-sided colonic involvement 4

Moderate-to-severe disease:

• Prednisolone 40 mg daily (taper over 8 weeks) 4
• Budesonide 9 mg daily for isolated ileocecal disease (marginally less effective than prednisolone) 4
• Infliximab 5 mg/kg for severe disease 4

Adjunctive/alternative options:

• Azathioprine/mercaptopurine as steroid-sparing agents (slow onset precludes monotherapy) 4
• Metronidazole 10-20 mg/kg/day for colonic/treatment-resistant disease (not first-line due to side effects) 4
• Sulfasalazine 4 g/daily effective but high side effect profile 4

Critical Pitfalls to Avoid

1. Do not use antiperistaltic agents or opiates - they increase toxic megacolon risk 5
2. Do not delay corticosteroids while awaiting stool cultures in severe colitis 4
3. Do not taper prednisolone too rapidly - increases early relapse 4
4. Do not use corticosteroids for maintenance - only for induction 3
5. Do not use probiotics, curcumin, or FMT outside clinical trials - insufficient evidence and risks delaying effective therapy 1
6. Treat proximal constipation in distal colitis with bulking agents/laxatives 4
7. Consider C. difficile testing in all flares, especially if recent antibiotics 5