What medications are used to treat inflammatory bowel disease?

Medications for Inflammatory Bowel Disease

For inflammatory bowel disease (IBD), the most effective first-line medications are aminosalicylates for ulcerative colitis and corticosteroids for moderate to severe Crohn's disease, with immunomodulators and biologics reserved for refractory cases. 1

Ulcerative Colitis Treatment

Mild to Moderate Disease

• First-line therapy: Oral aminosalicylates (mesalazine 2-4g daily, olsalazine 1.5-3g daily, or balsalazide 6.75g daily) are the cornerstone of treatment for mild to moderate ulcerative colitis 1, 2
• For distal disease (proctitis), combination therapy with topical mesalazine 1g daily plus oral mesalazine is more effective than either treatment alone 1, 2
• Topical formulation should be selected based on disease extent: suppositories for disease limited to rectum, foam or liquid enemas for more proximal disease 1, 3
• Once daily adequate dosing is as effective as divided dose regimens for both induction and maintenance of remission 2

Moderate to Severe Disease

• Patients who fail to improve on combination therapy should be treated with oral prednisolone 40mg daily, with gradual tapering over 8 weeks 1
• Topical agents may be used as adjunctive therapy with oral prednisolone 1
• Proximal constipation should be treated with stool bulking agents or laxatives 1, 2

Severe Disease

• Patients with severe disease require hospitalization and intensive intravenous therapy 1
• Intravenous steroids (hydrocortisone 400mg/day or methylprednisolone 60mg/day) are the mainstay of treatment 1
• Ciclosporin may be effective for severe, steroid-refractory colitis 1

Maintenance Therapy

• Patients should receive maintenance therapy with aminosalicylates (≥2g/day), azathioprine, or mercaptopurine to reduce the risk of relapse 1, 2
• For chronic active steroid-dependent disease, azathioprine (1.5-2.5mg/kg/day) or mercaptopurine (0.75-1.5mg/kg/day) should be used rather than long-term steroids 1, 2

Crohn's Disease Treatment

Mild Disease

• High-dose mesalazine (4g/daily) may be sufficient initial therapy for mild ileocolonic Crohn's disease, though it has limited benefit compared to its efficacy in ulcerative colitis 1, 2

Moderate to Severe Disease

• Oral corticosteroids such as prednisolone 40mg daily are appropriate for moderate to severe disease 1
• Budesonide 9mg daily is appropriate for isolated ileo-cecal disease with moderate activity, with fewer systemic side effects than prednisolone 1
• Intravenous steroids are appropriate for patients with severe disease 1

Fistulating and Perianal Disease

• Metronidazole 400mg three times daily and/or ciprofloxacin 500mg twice daily are appropriate first-line treatments for simple perianal fistulae 1
• Azathioprine or mercaptopurine are effective for simple perianal fistulae or enterocutaneous fistulae 1
• Infliximab (5mg/kg at weeks 0,2, and 6) is effective for patients with fistulizing Crohn's disease refractory to other treatments 1, 4

Alternative Therapies

• Elemental or polymeric diets may be used to induce remission in patients with active Crohn's disease who have contraindications to corticosteroid therapy 1
• Total parenteral nutrition is appropriate adjunctive therapy in complex, fistulating disease 1
• Metronidazole (10-20mg/kg/day) may be used in selected patients with colonic or treatment-resistant disease 1

Immunomodulators and Biologics

Azathioprine and Mercaptopurine

• Used for steroid-dependent disease and maintenance of remission 1
• Typical dosing: azathioprine 1.5-2.5mg/kg/day or mercaptopurine 0.75-1.5mg/kg/day 1, 5
• Monitor for myelosuppression, hepatotoxicity, and opportunistic infections 5, 6
• Consider TPMT and NUDT15 testing in patients with severe myelosuppression 5

Infliximab

• Effective for moderate to severe Crohn's disease and fistulizing disease 1, 4
• Standard dosing: 5mg/kg at weeks 0,2, and 6, then every 8 weeks 4
• In clinical trials, 39-46% of patients achieved clinical remission at week 30 compared to 25% with placebo 4
• Best avoided in patients with obstructive symptoms or sepsis 1, 4

Common Pitfalls to Avoid

• Overprescribing mesalamine for Crohn's disease (less effective than in ulcerative colitis) 2, 7
• Using inadequate dosing of aminosalicylates (<2g/day) for maintenance therapy 2
• Not considering combination therapy (topical plus oral) when response to monotherapy is suboptimal 1, 2
• Inappropriate or prolonged use of steroids (for perianal Crohn's disease, when sepsis is present, or for maintenance) 7
• Delayed introduction or underdosing with azathioprine, mercaptopurine, or methotrexate 7
• Failing to treat proximal constipation in patients with distal disease 1, 2
• Not supplementing with folic acid when using methotrexate 2