Drug reference

Mesalamine

5-aminosalicylic acid (5-ASA) anti-inflammatory agent · GI Anti-inflammatory

Also known as Mesalazine, 5-aminosalicylic acid, 5-ASA

START

Confirm UC diagnosis and disease extent (rectal, left-sided, pancolitis). Check baseline creatinine (nephrotoxicity risk, though rare). Formulation choice depends on disease location.

TYPICAL MAX

4.8g/day oral. For proctitis, topical (suppository/enema) is more effective than oral alone. Combination oral + topical is most effective for left-sided disease.

STOP IF

Worsening symptoms with fever (acute intolerance syndrome), signs of nephrotoxicity (rising creatinine), severe rash, SJS/TEN, signs of pericarditis (chest pain, friction rub).

WATCH

Renal function annually (interstitial nephritis risk, though rare). Acute intolerance syndrome may mimic flare—consider if symptoms worsen after starting. Formulation matters: Pentasa releases throughout small bowel and colon; Asacol/Lialda release in terminal ileum/colon; Apriso is delayed-release QD formulation.

CDSCO approvedJan AushadhiATC A07EC02

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 1h · Onset ~1 hour
PEAK: 8h · Tmax 4-12 hours (formulation-dependent)
t½: 3.5h · t½ 1-6 hours
DURATION: 10h · 8-12 hours per dose

EXCRETION

Fecal as acetylated metabolite (~80%)

route + CYP

INTERACTIONS

—

none in our sources

PREGNANCY

Preferred treatment for UC in pregnancy—safe, minimal systemic absorption. No teratogenic effects. Continue maintenance during pregnancy to prevent flare.

FDA category + note

Available in India

83 branded formulations. Look up specific brands in the Drugs workspace.

Jan Aushadhi — generic available at GoI pharmacies

Mechanism

Topical anti-inflammatory effect on colonic mucosa. Inhibits cyclooxygenase and lipoxygenase pathways, reducing prostaglandin and leukotriene synthesis. Scavenges free radicals, inhibits NF-κB activation, and modulates mucosal cytokine production. Acts locally in the GI tract with minimal systemic absorption.

Indications

Mild to moderate ulcerative colitis (induction and maintenance of remission)Crohn's disease (mild colonic disease—limited evidence)Maintenance of remission in ulcerative colitis (long-term)

Dosing

Adult: UC induction: 2.4-4.8g/day PO divided TID-QID (Asacol HD 800mg: 2 tablets TID). UC maintenance: 1.2-2.4g/day PO divided BID-QID. Rectal (enema): 1-4g daily or QHS for proctitis/distal colitis. Suppository: 1g daily for proctitis.
Pediatric: >5 years: 30-50mg/kg/day divided BID-TID (max 75mg/kg/day or 4.8g).
Renal adjustment: No adjustment for mild-moderate. Severe renal impairment: avoid (nephrotoxicity risk).
Hepatic adjustment: Use caution; avoid in severe hepatic impairment.
Geriatric: No specific adjustment; monitor renal function closely.
Max dose: 4.8g/day (oral); 4g/day (rectal)

Pharmacokinetics

Onset

Symptomatic improvement 3-7 days; mucosal healing 2-4 weeks

Peak effect

Tmax 4-12 hours (formulation-dependent); delayed-release tablets release in terminal ileum/colon

Duration

8-12 hours per dose

Half-life

~1-6 hours (acetylated metabolites); parent compound minimally absorbed

Bioavailability

~10-30% (oral; extensive first-pass and local metabolism in gut wall)

Protein binding

~43%

Metabolism

Extensive acetylation in gut mucosa and liver to N-acetyl-5-ASA (inactive metabolite)

Excretion

~80% fecal (majority as N-acetyl-5-ASA); ~20% renal (metabolites)

Contraindications

Hypersensitivity to salicylates or aminosalicylates
Severe hepatic or renal impairment
Salicylate hypersensitivity (asthma, urticaria)
Children <2 years (some formulations)

Side effects

Common

HeadacheNauseaAbdominal pain / crampingFlatulenceDiarrheaRash

Serious

Acute intolerance syndrome (worsening colitis symptoms—may mimic disease flare)
Nephrotoxicity (interstitial nephritis, rare)
Hepatotoxicity (elevated LFTs)
Pericarditis / myocarditis (rare)
Blood dyscrasias (agranulocytosis, aplastic anemia—rare)
Hypersensitivity pneumonitis
Severe cutaneous adverse reactions

Pregnancy & lactation

Pregnancy

Preferred treatment for UC in pregnancy—safe, minimal systemic absorption. No teratogenic effects. Continue maintenance during pregnancy to prevent flare.

Lactation

Excreted in breast milk in very small amounts (<1% of maternal dose); negligible infant exposure. Compatible with breastfeeding.