[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › Aminosalicylates (5-ASA)

[Pharmacology](https://durgical.com/en/pharmacology/) · Class

# Aminosalicylates (5-ASA)

Anti-inflammatory medicines that deliver 5-aminosalicylic acid to the inflamed bowel. A base treatment for mild to moderate ulcerative colitis.

Updated 2026-11-01

## What they are

Medicines built around 5-aminosalicylic acid (5-ASA, mesalazine), which acts topically on the bowel lining. Azo compounds (sulfasalazine, olsalazine, balsalazide) release 5-ASA when colonic bacteria split the azo bond; mesalazine formulations release it by pH or time.

## Mechanism of action

5-ASA works on the mucosa rather than through the bloodstream. It dampens mediators from the cyclooxygenase and lipoxygenase pathways, interferes with inflammatory cytokines (including NF-κB activity) and scavenges reactive oxygen species. The exact mechanism is not fully known.

Target: Colonic mucosa (local anti-inflammatory action of 5-ASA)

## Key points

- They induce and maintain remission in mild to moderate ulcerative colitis; benefit in Crohn's disease is less clear.
- Sulfasalazine = 5-ASA + sulfapyridine; most adverse effects come from sulfapyridine and are worse in slow acetylators.
- Sulfasalazine lowers folate absorption and can cause reversible oligospermia.
- Kidney injury (interstitial nephritis) is a rare effect of all 5-ASA products: check kidney function.
- Contraindicated in salicylate allergy; sulfasalazine also in sulfonamide allergy and porphyria.

## Drugs in this class

- [**Sulfasalazine** A pro-drug that colonic bacteria split into 5-ASA, which calms the colon, and sulfapyridine. Used in ulcerative… Colonic mucosa (5-ASA) and immune cells (anti-inflammatory and immunomodulatory effects)](https://durgical.com/en/pharmacology/sulfasalazine/)
- [**Mesalazine** 5-aminosalicylic acid packaged to reach the inflamed bowel. It calms the lining locally and is a base treatment for… Colonic mucosa (local anti-inflammatory action)](https://durgical.com/en/pharmacology/mesalazine/)

## Others in the class

- Olsalazine
- Balsalazide

## Test yourself

Think of the answer, then tap the question to see it.

## Which part of sulfasalazine is the active anti-inflammatory one in ulcerative colitis?

5-aminosalicylic acid (5-ASA); sulfapyridine is mainly the carrier and causes most adverse effects.

## What frees 5-ASA from sulfasalazine in the colon?

Bacterial azoreductases that split the azo bond.

## Which kidney complication is linked to 5-ASA drugs?

Interstitial nephritis and, rarely, kidney failure; kidney function is checked before and during treatment.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/classes/aminosalicylates/)

[← All of pharmacology](https://durgical.com/en/pharmacology/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=A07EC) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); [DailyMed - MESALAMINE tablet, delayed release](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=00f77203-3615-47e8-ae25-6e1cf8a2a00a) (DailyMed (U.S. National Library of Medicine), 2026); [DailyMed - SULFASALAZINE tablet, delayed release](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=257cee60-b68f-4c2b-b57d-8e4d73d17e09) (DailyMed (U.S. National Library of Medicine), 2026); Farmacología básica y clínica (Katzung), 16.ª ed., cap. 62 (McGraw Hill, 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/classes/aminosalicylates/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/aminosalicylates/