Pentasa (Mesalamine (5-Aminosalicylic Acid / 5-ASA))
Also sold as: Pentasa, Asacol, Mesacol, Mesasal, Salofalk
Pregnancy
Cat B
Lactation
Caution
Schedule
H
Forms
Tablet CR/SR 400mg, 500mg, 800mg +4
Indications
- Ulcerative colitis (UC) — mild to moderate acute flares (induction of remission)
- UC — maintenance of remission (significantly reduces relapse rate)
- Crohn's colitis — mild flares (limited evidence; not for small bowel Crohn's)
Adult Dosing
UC — mild-moderate acute flare (induction)
2.4–4.8 g/day PO in divided doses (or once daily with MR formulations)
Higher doses (4.8 g) for more active disease. Rectal mesalamine (suppository 1g OD or enema 2–4g OD) preferred for left-sided/rectal disease — combination oral + rectal superior to either alone.
UC — maintenance of remission
1.2–2.4 g/day PO (once daily preferred for adherence)
Continuous lifelong — stopping increases relapse risk
Proctitis/left-sided colitis (rectal)
Suppository 1g OD (proctitis) or Enema 2–4g OD at bedtime (left-sided)
Induction 6–8 weeks; maintenance ongoing
Pediatric Dosing
Granules can be mixed with soft food for younger children
Renal Dose Adjustment
| CrCl / eGFR | Dose Adjustment |
|---|---|
| CrCl < 30 mL/min | Avoid — risk of nephrotoxicity (interstitial nephritis); rectal formulations safer but still use with caution |
Hepatic Adjustment
No specific adjustment — hepatic and colonic acetylation; monitor LFTs
Pregnancy & Lactation
Pregnancy: Category B
Mesalamine is the preferred drug for maintaining UC remission in pregnancy. Uncontrolled UC is far more harmful to pregnancy than the drug. Avoid suppositories containing dibutyl phthalate (DBP — some older brands); use DBP-free formulations in pregnancy. Generally considered safe.
Lactation: Caution
Mesalamine and its metabolite (Ac-5-ASA) are excreted in breast milk. Risk of neonatal diarrhoea reported. Generally considered acceptable (especially oral formulations) but monitor infant for loose stools. Rectal formulations: very low systemic absorption — preferable during breastfeeding.
Top Drug Interactions
| Interacting Drug | Effect | Severity |
|---|---|---|
| Azathioprine / 6-mercaptopurine | Mesalamine inhibits TPMT enzyme — increases azathioprine/6-MP levels and bone marrow toxicity risk; monitor FBC closely | Major |
| Warfarin | Possible increased anticoagulant effect — monitor INR | Moderate |
| Lactulose / acidic medications | May disrupt pH-dependent release of some mesalamine formulations (Asacol — releases at pH > 7) | Minor |
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Side Effects
Common
- Headache
- Nausea
- Abdominal pain
- Diarrhoea (paradoxical worsening — usually settles)
- Rash
- Arthralgia
Serious / Discontinue If
- Interstitial nephritis (rare but serious — monitor creatinine; renal biopsy if creatinine rises)
- Mesalamine-induced acute intolerance syndrome (5% — worsening of colitis symptoms, fever, rash — can mimic flare; stop mesalamine)
- Cardiac toxicity (myocarditis, pericarditis — rare)
- Blood dyscrasias (rare — leucopenia, agranulocytosis)
Contraindications
- Significant renal impairment (CrCl < 30 mL/min)
- Salicylate hypersensitivity
- Active peptic ulcer
Available Indian Brands
| Brand | Manufacturer | Price (approx) |
|---|---|---|
| Pentasa 500mg CR | Ferring India | 50 tab ₹895 |
| Mesacol 400mg | Sun Pharma | 30 tab ₹285 |
| Salofalk 500mg | Dr Falk Pharma/Elder India | 30 tab ₹565 |
| Mesasal 250mg | Cipla | 30 tab ₹185 |
Monitoring Required
- Serum creatinine and urinalysis (at baseline, 3 months, and annually — nephrotoxicity)
- FBC (if on concurrent azathioprine — TPMT interaction)
- LFTs (baseline and 3-monthly)
- Stool frequency and consistency (disease activity)
- Annual colonoscopy surveillance (UC — colorectal cancer risk)
Patient Counseling Points
- Take mesalamine regularly every day — even when you feel well (it prevents relapse)
- Swallow tablets whole — do not crush or chew (disrupts modified-release mechanism)
- Suppository/enema: best used at bedtime and retained for at least 3 hours
- Report any new rash, fever, worsening diarrhoea with abdominal pain after starting — rare drug reaction
- Kidney function test annually — mesalamine rarely causes kidney problems that can be caught early
- Mesalamine is very safe long-term — much safer than steroids for maintenance
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Clinically reviewed by: Dr. Pradeep Nair, DM (Gastroenterology), Consultant Gastroenterologist
Last reviewed: 2026-04-01
References
- ECCO UC Guidelines 2022
- AGA Ulcerative Colitis Management Guidelines 2020
- BSG IBD Guidelines 2019
- BNF — Mesalamine
- Indian Society of Gastroenterology IBD Guidelines