Mesalazine (5-aminosalicylic acid or 5-ASA) is a first-line, locally acting anti-inflammatory aminosalicylate drug primarily used for the treatment of mild to moderate ulcerative colitis and maintenance of remission. It acts topically on the colonic mucosa to reduce inflammation. In the Indian context, it is a cornerstone therapy for inflammatory bowel disease (IBD), available in various oral and rectal formulations.
Adult: Active Disease: 2-4.8 g/day in 2-3 divided doses. Common Indian regimen: 500mg tablets: 4-6 tablets per day (2-3 g/day). Maintenance: 1.5-3 g/day in 2-3 divided doses. Common: 2-4 tablets per day (1-2 g/day).
Note: Swallow tablets whole with a full glass of water; do NOT crush, chew, or break. Take with or after food to reduce GI upset. For pH-dependent tablets (e.g., Asacol), consistency in timing relative to meals is important. Do not take antacids within 1-2 hours of dose as they may alter pH-dependent release.
Mesalazine's primary mechanism is topical anti-inflammatory action on the colonic mucosa. It is a prodrug/site-specific agent that acts locally. Its exact mechanism is multifactorial: it inhibits cyclooxygenase and lipoxygenase pathways, reducing prostaglandin and leukotriene synthesis; scavenges reactive oxygen species; inhibits neutrophil chemotaxis and degranulation; and interferes with nuclear factor kappa B (NF-κB) activation, thereby reducing the production of pro-inflammatory cytokines (TNF-α, IL-1, IL-6).
Pregnancy: Pregnancy Category B. Considered relatively safe. Use only if clearly needed. Adequate human data suggests low risk. Monitor disease activity closely as flare-ups pose greater risk than drug.
Driving: Unlikely to affect ability. Dizziness is a rare side effect.
| Warfarin | Mesalazine may potentiate anticoagulant effect, increasing INR and bleeding risk. | Major |
| Azathioprine / 6-Mercaptopurine | Concurrent use may increase risk of blood dyscrasias (leukopenia, pancytopenia). | Major |
| Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) | May increase risk of nephrotoxicity (additive renal effects). | Major |
| Lactulose | May lower colonic pH, potentially affecting release of pH-dependent mesalazine formulations. | Moderate |
| Thiopurine Methyltransferase (TPMT) Inhibitors | May alter metabolism of thiopurines if used concurrently, increasing toxicity risk. | Moderate |
| Digoxin | Mesalazine may reduce absorption of digoxin. | Moderate |
Same composition (Mesalazine (500mg)), different brands: