[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Mucolytics and supportive cystic fibrosis therapies](https://durgical.com/en/pharmacology/classes/mucolytics-and-supportive-cystic-fibrosis-therapies/) › Dornase alfa

# Dornase alfa

## Mucolytics and supportive cystic fibrosis therapies?

Mucolytics and supportive cystic fibrosis therapies

An inhaled enzyme that cuts the DNA in thick cystic fibrosis sputum, making it easier to cough up and reducing lung infections.

Updated Nov 1, 2026

## Quick facts

**Group**
[Mucolytics and supportive cystic fibrosis therapies](https://durgical.com/en/pharmacology/classes/mucolytics-and-supportive-cystic-fibrosis-therapies/)

**Target**
Extracellular DNA in airway secretions (dornase alfa is recombinant human deoxyribonuclease I)

**Used for**
Cystic fibrosis

**Key effects**
Voice changes and hoarseness · Sore throat · Rash

**Monitor**
Lung function · Frequency of respiratory infections

**ATC**
R05CB13

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

Dornase alfa is a recombinant form of human deoxyribonuclease I. In cystic fibrosis, infected and inflamed airways fill with secretions rich in DNA, which makes them thick and sticky. Inhaled dornase alfa cuts this DNA into smaller pieces, so the sputum becomes less viscous and is easier to clear. Clearer airways mean better lung function and fewer infections.

- Infected cystic fibrosis airways fill with DNA-rich, sticky secretions
- Inhaled dornase alfa cuts the DNA into small fragments
- Sputum becomes less viscous and is cleared more easily
- Lung function improves and infections become less frequent

## Indications

- Cystic fibrosis, to improve lung function and reduce respiratory infections [Cystic fibrosis →](https://durgical.com/en/conditions/cystic-fibrosis/)

## Adverse effects

### Common

- Voice changes and hoarseness
- Sore throat
- Eye irritation
- Rash

### Serious (rare, important)

- Increasing difficulty breathing
- Chest pain

## Contraindications

- Hypersensitivity to dornase alfa or any component of the product

## Key interactions

**Other nebulised medicines**
It is not diluted or mixed with other drugs in the nebuliser; it is inhaled on its own

## What is monitored

- Lung function (spirometry)
- Frequency of respiratory infections
- Voice and throat symptoms

## Administration and safety

- Inhaled with a compatible nebuliser; never diluted or mixed with other medicines in the nebuliser
- Kept refrigerated and protected from light; cloudy or discoloured solution is discarded
- The nebuliser is cleaned regularly according to the instructions

## Pregnancy and breastfeeding

Human data are limited; use in pregnancy is decided with the cystic fibrosis team.

## Nursing care

- Teach nebuliser technique and cleaning
- Coordinate with airway clearance and physiotherapy
- Ask about hoarseness, sore throat and any new breathlessness or chest pain
- Check storage: refrigerated, protected from light

## Pharmacokinetics

**Absorption**
Inhaled by nebuliser; acts locally on the secretions in the airways

## Memory aid

DORNase = «DNA-snipping scissORs»: it cuts the DNA that makes cystic fibrosis sputum sticky.

## Test yourself

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

## What does dornase alfa break down?

Extracellular DNA in airway secretions; it is a recombinant human deoxyribonuclease I.

## How is dornase alfa given, and what must not be done in the nebuliser?

By inhalation with a nebuliser, on its own: it is never diluted or mixed with other medicines.

## Which adverse effects of dornase alfa affect the voice and throat?

Hoarseness or voice change and sore throat.

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

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

## Connections

## Related drugs 4

- [Acetylcysteine](https://durgical.com/en/pharmacology/acetylcysteine/)
- [Ivacaftor](https://durgical.com/en/pharmacology/ivacaftor/)
- [Elexacaftor + tezacaftor + ivacaftor](https://durgical.com/en/pharmacology/elexacaftor-tezacaftor-ivacaftor/)
- [Tobramycin](https://durgical.com/en/pharmacology/tobramycin/)

## Related conditions 1

- [Cystic fibrosis](https://durgical.com/en/conditions/cystic-fibrosis/)

[← Back to the class: Mucolytics and supportive cystic fibrosis therapies](https://durgical.com/en/pharmacology/classes/mucolytics-and-supportive-cystic-fibrosis-therapies/)

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

Sources: [Dornase Alfa: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a694002.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=R05CB13) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); [Cystic fibrosis: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/cystic-fibrosis/) (MedlinePlus (U.S. National Library of Medicine), 2026).

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Representative model, for educational purposes only.

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