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

# Balsalazide

## 5-ASA?

Aminosalicylates (5-ASA)

A prodrug that carries mesalazine (5-ASA) to the colon, where bacteria release it. Used for mild to moderate active ulcerative colitis.

Updated Nov 1, 2026

## Quick facts

**Group**
[Aminosalicylates (5-ASA)](https://durgical.com/en/pharmacology/classes/aminosalicylates/)

**Target**
Local anti-inflammatory action of mesalazine on the colonic mucosa (cyclooxygenase and lipoxygenase products)

**Key effects**
Headache · Abdominal pain · Respiratory infection

**Monitor**
Renal function before · Blood counts

**ATC**
A07EC04

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Balsalazide is mesalazine joined by an azo bond to an inert carrier. It passes the stomach and small bowel intact; in the colon bacterial azoreductases split it into mesalazine and the carrier, which is barely absorbed. Mesalazine acts on the colonic epithelium; it probably reduces production of prostaglandins and leukotrienes, which are increased in ulcerative colitis.

- Balsalazide reaches the colon intact
- Colonic bacteria cut the azo bond and release mesalazine
- Mesalazine calms mucosal inflammation locally

## Indications

- Mildly to moderately active ulcerative colitis in adults and children aged 5 years and older [Ulcerative colitis →](https://durgical.com/en/conditions/ulcerative-colitis/)

## Adverse effects

### Common

- Headache
- Abdominal pain, diarrhoea, nausea, vomiting
- Respiratory infection
- Joint pain

### Serious (rare, important)

- Kidney injury
- Mesalazine-induced acute intolerance syndrome, which can look like a colitis flare
- Hypersensitivity reactions including myocarditis and pericarditis
- Liver failure; severe skin reactions
- Kidney stones not seen on standard X-ray or CT

## Contraindications

- Hypersensitivity to salicylates, aminosalicylates, balsalazide or its metabolites

## Key interactions

**NSAIDs and other nephrotoxic drugs**
Higher risk of kidney injury; renal function is checked

**Azathioprine or mercaptopurine**
Higher risk of blood disorders; blood counts are checked

**Urinary normetanephrine tests**
Falsely high results with some laboratory methods

## What is monitored

- Renal function before and during treatment
- Blood counts, especially in older patients
- Worsening colitis symptoms

## Administration and safety

- Capsules are swallowed whole; if needed they can be opened onto applesauce, which may stain teeth or tongue.
- Can be taken with or without food; good fluid intake is encouraged.
- Avoided in pyloric stenosis or other upper GI obstruction.

## Pregnancy and breastfeeding

Published data on mesalazine in pregnancy have not shown a reliable link with birth defects or miscarriage; active ulcerative colitis itself carries risks.

## Nursing care

- Ask about aspirin or salicylate allergy and kidney disease before starting.
- Check creatinine at baseline and periodically.
- Teach that cramping, bloody diarrhoea, fever or rash may be drug intolerance, not just a flare, and must be reported.
- Advise sun protection if the skin is sensitive.

## Pharmacokinetics

**Absorption**
Low and variable systemic absorption of balsalazide and its metabolites

**Metabolism**
Split by colonic bacteria; mesalazine is then acetylated

## Memory aid

«BALSA = a boat»: balsalazide ferries mesalazine to the colon, where bacteria unload it.

## Test yourself

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

## How is balsalazide activated?

Colonic bacterial azoreductases split it and release mesalazine.

## Which organ function is checked before and during treatment?

Kidney function.

## Why can mesalazine intolerance be missed?

Its cramping, bloody diarrhoea and fever look like a colitis flare.

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

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Sulfasalazine](https://durgical.com/en/pharmacology/sulfasalazine/)
- [Mesalazine](https://durgical.com/en/pharmacology/mesalazine/)
- [Olsalazine](https://durgical.com/en/pharmacology/olsalazine/)

## Related conditions 1

- [Ulcerative colitis](https://durgical.com/en/conditions/ulcerative-colitis/)

[← Back to the class: Aminosalicylates (5-ASA)](https://durgical.com/en/pharmacology/classes/aminosalicylates/)

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

Sources: [DailyMed - BALSALAZIDE DISODIUM capsule](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f12ffa32-d14b-e9d9-e957-2ef08b64e8b4) (DailyMed (U.S. National Library of Medicine), 2023); [Balsalazide: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a699052.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=A07EC04) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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