Treatment of Crohn's Disease
For moderate to severe Crohn's disease, anti-TNF therapy (infliximab or adalimumab) should be used as first-line treatment, particularly in patients with risk factors for poor prognosis. 1
Treatment Algorithm by Disease Severity
Mild Disease (Ileocecal)
- Budesonide 9 mg/day is the preferred first-line agent for mild ileocecal Crohn's disease 1, 2
- Evaluate response at 4-8 weeks; if inadequate, escalate therapy 1
- High-dose mesalazine (4 g/day) may be considered for mild ileocolonic disease, though evidence is weaker 3
Mild Disease (Colonic Only)
Moderate to Severe Disease
First-Line Therapy (Biologic-Naive Patients)
The 2025 British Society of Gastroenterology guidelines and 2025 AGA guidelines represent the most current evidence and advocate for early advanced therapy in moderate to severe disease. 2, 4
Higher efficacy medications (first-line options): 4
- Infliximab
- Adalimumab
- Vedolizumab
- Ustekinumab
- Risankizumab
- Mirikizumab
- Guselkumab
Key decision point: Anti-TNF therapy (infliximab, adalimumab) is strongly recommended as first-line for moderate to severe disease with poor prognostic factors (strong recommendation, moderate-quality evidence) 1
- Combination therapy: When starting anti-TNF therapy, combine with thiopurine (azathioprine/mercaptopurine) over monotherapy to improve outcomes and pharmacokinetics 1
- Evaluate response at 8-12 weeks (strong recommendation) 1
- If response achieved, continue anti-TNF for maintenance (strong recommendation, high-quality evidence) 1
Alternative to Biologics (if contraindicated)
- Oral prednisone 40-60 mg/day for induction only (strong recommendation) 1
- Assess response at 2-4 weeks; if inadequate, modify therapy 1
- Never use corticosteroids for maintenance (strong recommendation) 1
Severe Disease Requiring Hospitalization
- IV methylprednisolone 40-60 mg/day (conditional recommendation) 1
- Evaluate response within 1 week (strong recommendation) 1
- If no response, immediately escalate to biologic therapy or consider surgery
Biologic-Exposed Patients (Failed Anti-TNF)
For patients who have failed anti-TNF therapy, the treatment hierarchy changes: 4
Higher efficacy options:
- Adalimumab (if switching within class)
- Risankizumab
- Guselkumab
- Upadacitinib (highest SUCRA ranking for biologic-exposed patients) 5
Intermediate efficacy options:
- Ustekinumab (strong recommendation, moderate-quality evidence) 1
- Mirikizumab
Lower efficacy (avoid):
- Vedolizumab (becomes less effective after anti-TNF failure) 4
Evaluate response:
Maintenance Therapy Strategy
Once remission is achieved:
- Continue the induction agent that worked (strong recommendation, high-quality evidence for anti-TNF) 1
- For suboptimal response or loss of response: dose optimization guided by therapeutic drug monitoring 1
- Do not switch between anti-TNF agents if patient is doing well (conditional recommendation) 1
Immunomodulator Maintenance
- Thiopurines may maintain remission in selected patients who achieved remission with corticosteroids (conditional recommendation) 1
- Parenteral methotrexate for corticosteroid-dependent/resistant disease (conditional recommendation) 1
- If no corticosteroid-free remission by 12-16 weeks, modify therapy 1
Critical Pitfalls to Avoid
Never use corticosteroids for maintenance - this is a strong recommendation across all guidelines 1, 2
Do not delay biologic therapy - The 2025 guidelines emphasize early advanced therapy for moderate-severe disease rather than the traditional step-up approach 2, 4
Avoid thiopurine monotherapy for induction - ineffective for inducing remission 1
Do not use probiotics, omega-3 fatty acids, marijuana, or naltrexone - strong recommendations against these 1
Assess response early and modify if needed - waiting too long with ineffective therapy allows disease progression 1, 2
Evidence Quality Considerations
The strongest evidence (high-quality, strong recommendations) supports:
- Anti-TNF therapy for moderate-severe disease 1
- Continuing successful induction therapy for maintenance 1
- Against corticosteroids for maintenance 1
The 2025 British Society of Gastroenterology guidelines 2 and 2025 AGA guidelines 4 represent the most current thinking, advocating for earlier use of advanced therapies (biologics and small molecules) over the traditional step-up approach with corticosteroids, particularly given the paradigm shift toward preventing long-term complications rather than just treating symptoms.