Gastrointestinal/Aminosalicylate (5-ASA)

Aminosalicylates (mesalazine)

also: mesalazine · sulfasalazine · 5-ASA

Overview

Topical anti-inflammatory for inflammatory bowel disease — first-line to induce + maintain remission in ulcerative colitis (less effective in Crohn's).

Mechanism

5-aminosalicylic acid acts topically on the colonic mucosa → inhibits prostaglandin/leukotriene synthesis and scavenges free radicals → reduces mucosal inflammation. Different formulations release at different gut levels (oral/rectal).

Indications

Ulcerative colitis (induce + maintain remission — first-line)
Mild Crohn's (limited role)

The agents

Mesalazine5-ASA

oral + rectal

Combine oral + rectal for distal colitis; rectal first-line for proctitis.

Sulfasalazine5-ASA + sulfapyridine

More side effects (the sulfa moiety); also used in rheumatoid arthritis.

Adverse effects

Nephrotoxicity (interstitial nephritis)serious

Monitor renal function.

Blood dyscrasias (report sore throat/bruising)serious

Sulfasalazine: reversible oligospermia, rash, GI upsetcommon

Cautions & contraindications

Salicylate hypersensitivityall

Significant renal impairment (caution)renal

Interactions

Monitoring & kinetics

Renal function; FBC

Oral ± rectal. First-line UC; cross-references sulfasalazine in rheumatology.

Choosing it

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Source: NICE NG130 — Ulcerative colitis · BNF — Aminosalicylates