Aerosolised mucolytics for cystic fibrosis

Aerosolised mucolytics (eg dornase alfa, hypertonic saline, mannitol) may be prescribed by specialists for patients with cystic fibrosis (CF). These drugs are initiated in the specialist CF centre.

Bronchodilators are sometimes used as pretreatment before mucolytics to prevent bronchoconstriction and improve pulmonary deposition.

Dornase alfa is recombinant human DNase, which cleaves extracellular DNA and reduces sputum viscosity. Aerosolised dornase alfa facilitates sputum clearance, improves lung function and reduces exacerbations in patients with CF.

The initial phase of therapy consists of a 3-month trial. Use:

Treatment can continue if there is no deterioration in forced expiratory volume in 1 second (FEV₁) during the trial, and if a clinical benefit is seen.

Nebulised hypertonic saline improves lung function and reduces acute infective exacerbations. A hypertonic saline challenge should be performed before it is prescribed because nebulised hypertonic saline may cause bronchospasm in susceptible patients.

Sodium chloride 6% solution is ideally used; sodium chloride 3% solution may be used in patients who do not tolerate the 6% solution.

Inhaled dry powder mannitol improves mucociliary clearance and lung function, and is used in patients with CF aged 6 years or older. Use:

A Mannitol Tolerance Test should be performed before it is prescribed because inhaled mannitol may cause bronchospasm.