mesalamine
Brand: Asacol, Lialda, Apriso, Pentasa
Prototype: sulfasalazine
Drug Class: anti-inflammatory (IBD)
Drug Family: GI agent
Subclass: 5-aminosalicylate (5-ASA) — direct release
Organ Systems: gastrointestinalimmunology
Mechanism of Action
5-ASA released directly in different colonic segments depending on formulation; inhibits prostaglandin and leukotriene synthesis locally; no sulfonamide component.
arachidonic acid pathway (COX, lipoxygenase) in colonic mucosa
Indications
- ulcerative colitis (mild-moderate)
- Crohn disease (colonic — maintenance)
Contraindications
- salicylate allergy
- severe renal impairment
Adverse Effects
Common
- headache
- GI upset
- rash
Serious
- nephrotoxicity (rare but monitor)
- mesalamine-induced pancreatitis/myocarditis (rare)
Pharmacokinetics (ADME)
| Absorption | 15-25% absorbed (formulation-dependent) |
| Distribution | moderate |
| Metabolism | hepatic and colonic N-acetylation |
| Excretion | renal |
| Half-life | 0.5-1.5 hours |
| Onset | 4-12 hours (delayed release) |
| Peak | 4-12 hours |
| Duration | variable |
| Protein Binding | 43-80% |
| Vd | moderate |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| azathioprine/6-MP | mesalamine inhibits TPMT — increases 6-TGN levels — myelosuppression risk | major |
| NSAIDs | additive renal toxicity | moderate |
Nursing Considerations
- No sulfonamide: fewer side effects than sulfasalazine — preferred for sulfa-allergic patients
- Formulation determines release location (Asacol HD = distal colon; Pentasa = small intestine and colon)
- Monitor renal function annually
- May inhibit TPMT — increased 6-MP/azathioprine toxicity
Clinical Pearls
- Formulation diversity: Asacol (pH-dependent release distal colon), Pentasa (time-release jejunum-colon), Lialda (MMX technology entire colon)
- TPMT inhibition: mesalamine + azathioprine combination — monitor CBC for myelosuppression
Safety Profile
Pregnancy generally-safe
Lactation insufficient-data
Renal Adjustment Required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.