Drugs for Inflammatory Bowel Disease
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Direct answer
Where the inflammation sits dictates both drug and delivery in inflammatory bowel disease: ulcerative colitis is a mucosal surface disease that mesalazine reaches topically — rectal preparations for proctitis, oral plus topical for left-sided disease — while Crohn's transmural inflammation demands systemic immunosuppression earlier. Corticosteroids induce remission but never maintain it; thiopurines (azathioprine) maintain steroid-free remission slowly, over two to three months; anti-TNF agents (infliximab, adalimumab) rescue refractory disease, with the gut-selective vedolizumab as the targeted alternative. Severity sets urgency: intravenous steroids with ciclosporin or infliximab rescue for acute severe colitis, colectomy when rescue fails.
What you must remember
- Mesalazine logic: active 5-aminosalicylic acid delivered to the site — suppositories and enemas for proctitis and left-sided disease, oral delayed-release for extensive colitis; the combination beats either alone.
- Sulfasalazine costs: the sulfa carrier brings rash, reversible oligospermia, orange discolouration of urine and tears, and folate interference — prescribe folic acid with it.
- Steroid ceiling: prednisolone about 40 mg to induce, never to maintain — budesonide with ileal release spares systemic exposure.
- Azathioprine package: onset 8-12 weeks; leukopenia (check TPMT and NUDT15 genetics where available), pancreatitis, hepatitis, and a small lymphoma excess; monitor counts and liver throughout.
- Anti-TNF discipline: infliximab at weeks 0, 2 and 6 then 8-weekly, combined with azathioprine (SONIC); screen every patient for latent tuberculosis and hepatitis B before the first dose.
- Vedolizumab: anti-alpha-4-beta-7 integrin, gut-selective lymphocyte blockade — systemic infection risk lower than anti-TNF.
- Acute severe colitis: intravenous hydrocortisone; assess at day three (stool frequency, CRP, radiology); rescue with ciclosporin 2 mg/kg or infliximab, with colectomy ready.
- Crohn's extras: weekly methotrexate with folate (never daily dosing), exclusive enteral nutrition as first-line induction in paediatric Crohn's.
Escalating therapy in a ulcerative colitis patient
A woman with left-sided colitis flares with blood and urgency. Step one: oral mesalazine plus a mesalazine enema, because topical plus oral outperforms either alone. She improves; maintenance mesalazine continues. Two flares within a year, or steroid dependence when prednisolone tapers — the definition that changes everything — trigger azathioprine, started while tapering steroids because its benefit takes two months. A year later she flares on azathioprine: anti-TNF or vedolizumab enter, after tuberculosis screening. Should she present toxic with 12 bloody stools and a dilating colon, the pathway compresses to hours — admission, intravenous steroids, day-three assessment, ciclosporin or infliximab rescue, and a surgeon consulted on day one, not day seven.
The Crohn's mirror runs one step ahead systemically: steroids and nutrition induce, thiopurines or methotrexate maintain, biologics rescue, and smoking cessation is the cheapest maintenance drug in the list.
The Indian angle: tuberculosis before biologics
India's latent tuberculosis burden makes pre-biologic screening the most tested and most consequential step in this chapter: chest radiograph, tuberculin or IGRA testing per local guidance, and in many Indian centres treatment of latent tuberculosis before or with anti-TNF initiation. Indian gastroenterology consensus guidance is explicit that infliximab-related tuberculosis reactivation is disproportionately disseminated and extrapulmonary. Biosimilar infliximab and adalimumab transformed access in India's private sector; azathioprine remains the public-sector maintenance backbone. Report thiopurine leukopenia and tuberculosis reactivation to the PvPI.
Frequently asked questions
Why are steroids never used as maintenance therapy in IBD?
They lose efficacy and accumulate toxicity — osteoporosis, diabetes, infection — without preventing relapse; maintenance belongs to mesalazine, thiopurines or biologics.
Why screen for tuberculosis before anti-TNF therapy?
TNF blockade reactivates latent tuberculosis at high rates; in India's high-burden setting, reactivation is often disseminated — screen, treat latent infection, then start.
What are sulfasalazine's specific adverse effects beyond mesalazine?
The sulphasalazine carrier causes rash, reversible oligospermia, orange discolouration of secretions and folate depletion; supplement folic acid.
How is acute severe ulcerative colitis rescued after steroid failure?
Intravenous ciclosporin 2 mg/kg or infliximab as rescue therapy around day three, with colectomy available if response is absent — a joint surgical decision from admission.
What makes vedolizumab mechanistically distinct?
It blocks alpha-4-beta-7 integrin selectively in gut lymphocyte trafficking, sparing systemic immunity — fewer systemic infections than anti-TNF.