What is the initial treatment regimen for patients with colitis?

Initial Treatment for Colitis

For patients with colitis, the initial treatment regimen should consist of aminosalicylates (5-ASA), specifically oral mesalamine ≥2.4 g/day combined with topical mesalamine enemas ≥1 g/day for mild to moderate ulcerative colitis. 1

Treatment Based on Disease Severity and Extent

Mild to Moderate Ulcerative Colitis

• First-line therapy:
  • Oral mesalamine ≥2.4 g/day (once-daily dosing is as effective as divided doses)
  • Topical mesalamine enemas ≥1 g/day
  • Standard dose is typically 2-3 g/day for extensive or left-sided UC 1

Left-sided Disease

• Start with combination of oral and topical mesalamine
• If no response within 10-14 days or incomplete relief after 40 days, add oral corticosteroids 1

Extensive Disease

• Combination of oral mesalamine ≥2.4 g/day plus mesalamine enema 1 g/day as first-line treatment 1
• For non-responders to mesalamine, progress to systemic corticosteroids 1

Moderate to Severe Disease

• Systemic corticosteroids are indicated
• For patients who fail to respond to initial therapy, consider biologics such as infliximab 2
  • Infliximab dosing: 5 mg/kg given as intravenous induction at 0,2, and 6 weeks followed by maintenance regimen of 5 mg/kg every 8 weeks 2

Acute Severe Colitis Management

• Initial treatment:

  • Intravenous corticosteroids (methylprednisolone 60 mg/day or hydrocortisone 100 mg four times daily)
  • Intravenous fluid and electrolyte replacement
  • Thromboprophylaxis with low-molecular-weight heparin 1

• Diagnostic workup:

  • Stool cultures and Clostridium difficile toxin assay
  • Unprepared flexible sigmoidoscopy and biopsy (if possible)
  • Complete blood count, inflammatory markers (CRP), electrolytes, liver function tests 1

Optimization Strategies

• Add rectal mesalamine to oral therapy
• Use once-daily dosing for better compliance
• Increase to high-dose mesalamine (>3 g/day) with rectal mesalamine for suboptimal response 1
• For pediatric patients weighing at least 24 kg, weight-based dosing of mesalamine has shown efficacy 3

Important Considerations and Pitfalls

• Avoid these medications in acute colitis:

  • Anticholinergics
  • Anti-diarrheals
  • Non-steroidal anti-inflammatory drugs
  • Opioids (can worsen condition) 1

• Antimotility agents can precipitate toxic megacolon 1

• Premedication before infliximab:

  • Consider antihistamines, acetaminophen, and/or corticosteroids to prevent infusion reactions 2

• Monitor for complications:

  • Test for C. difficile and other pathogens before starting immunosuppressive therapy
  • Ensure adequate potassium replacement to prevent colonic dilatation
  • Implement thromboprophylaxis due to high thrombotic risk in colitis patients 1

• Surgical consultation:

  • If no improvement or deterioration within 48-72 hours of medical therapy
  • If complications such as free perforation, life-threatening hemorrhage, or generalized peritonitis occur 1

Treatment Progression

If patients fail to respond to initial aminosalicylate therapy within 10-14 days, treatment should be escalated to systemic corticosteroids. For those who don't respond to corticosteroids, biologics such as infliximab should be considered, especially for moderate to severe disease 1, 2.