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Mucolytic (recombinant DNase enzyme) Pregnancy: Limited data — use only if benefit outweighs risk. Continue if pregnancy occurs in established CF treatment under specialist guidance.

Dornase alfa (recombinant human DNase)

Brand names: Pulmozyme

Adult dose

Dose: 2.5 mg (1 vial) nebulised OD via jet nebuliser. Some patients (FVC <40% predicted) may benefit from BD.
Route: Inhalation (nebuliser)
Frequency: Once daily (occasionally BD)
Use with a jet nebuliser (e.g., PARI LC Plus) and compatible compressor. Do NOT mix with other nebulised drugs in the chamber. Refrigerate (2–8°C); discard if cloudy.

Paediatric dose

Route: Inhalation (nebuliser)
Frequency: Once daily
Licensed from age 5 (some specialists initiate from age 3–5 off-label). Same dose 2.5 mg OD as adults — not weight-adjusted.

Clinical pearls

  • Specifically licensed for cystic fibrosis — cleaves extracellular DNA released from neutrophils in CF airway mucus, reducing viscosity.
  • Improves FEV1 by ~6% and reduces pulmonary exacerbation frequency by ~28% (Fuchs et al. NEJM 1994).
  • Use ONLY with a jet nebuliser — ultrasonic nebulisers inactivate the enzyme.
  • Sequence in CF airway clearance regime: short-acting bronchodilator → dornase alfa → 30 min wait → chest physiotherapy / hypertonic saline.
  • Typically given mornings; avoid bedtime to allow secretion clearance during the day.
  • Non-CF bronchiectasis: NOT recommended (HARM signal in non-CF bronchiectasis trials — increased exacerbations).
  • Specialist CF/respiratory centre prescribing only.

Contraindications

  • Hypersensitivity to dornase alfa or hamster CHO cell-derived products

Side effects

  • Voice alteration / dysphonia (very common — usually mild and transient)
  • Pharyngitis, laryngitis
  • Chest discomfort
  • Conjunctivitis (if aerosol contacts eyes — wear eye protection during nebulisation)
  • Rash
  • Decreased lung function transiently after first doses (usually self-limiting)
  • Anaphylaxis (rare)

Interactions

  • Other nebulised therapies: do not mix in nebuliser chamber — give separately. Sequence: bronchodilator first, then dornase alfa, then chest physiotherapy.

Monitoring

  • FEV1 every 3 months
  • Pulmonary exacerbations / sputum culture
  • Annual CF MDT review

Reference: BNFc; BNF 90; SmPC Pulmozyme; CF Trust Standards of Care 2024; Fuchs et al. NEJM 1994;331:637; NICE NG78 (CF management). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Pathways