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Nebulised and mucoactive agents make airway clearance more effective — hydrating the airways, thinning mucus, or delivering antibiotics directly to the lungs. This page is the clinician reference for those agents; for the patient-facing guide to nebulising at home and the eChamber device, see the Managing-at-home section.
Nebulised and mucoactive therapies are used to hydrate and loosen thick secretions and to deliver medicine as a fine mist to the airways. They include saline and hypertonic saline (for example MucoClear® 3% or 6%), mucolytics such as dornase alfa, bronchodilators, and inhaled antibiotics.1 For physiotherapy these agents are tightly linked to airway clearance and to the order of a session — a bronchodilator and mucoactive agent before clearance, and any nebulised antibiotic last, into cleared airways. The table below summarises the main agents and how they are used.
Mucoactive & airway-clearance adjunct agents
| Agent | Class & mechanism | Route & typical dose | Evidence-based indications | Implications for physiotherapy |
|---|---|---|---|---|
| Hypertonic saline 6–7% | Hyperosmolar agent — osmotically draws water into the airway | Nebulised 4 mL bd | CF (strong evidence); bronchiectasis (moderate evidence) | Bronchospasm risk on initiation — supervised first dose with pre- and post-spirometry. Always pre-treat with SABA. Schedule airway clearance immediately following |
| Hypertonic saline 3% | Hyperosmolar agent (lower concentration) | Nebulised 4 mL bd | Bronchiectasis — often preferred starting concentration in patients with airway reactivity | Better tolerated than 6–7% but smaller effect |
| Mannitol (Bronchitol) | Hyperosmolar agent — osmotic hydration of mucus delivered as dry powder | DPI 400 mg bd | CF (PBS-listed) | Bronchial Tolerance Test (BTT) required before initiation. Pre-treatment SABA mandatory |
| Dornase alfa (Pulmozyme) | Recombinant human DNase — enzymatically cleaves extracellular neutrophil DNA | Nebulised 2.5 mg once daily | Cystic fibrosis only. Not recommended in non-CF bronchiectasis | Schedule airway clearance approximately 30 minutes after dornase. Store refrigerated |
| N-acetylcysteine (oral) | Thiol mucolytic — cleaves disulphide bonds in mucin glycoproteins; also antioxidant | PO 600 mg bd or tds | COPD with chronic bronchitis (modest evidence); bronchiectasis (limited evidence) | Generally well-tolerated. GI upset. Effervescent tablets have characteristic sulfurous smell |
| N-acetylcysteine (nebulised) | Same as oral, delivered topically | Largely superseded | Limited current role | Substantial bronchospasm risk. Strong sulfurous odour |
| Carbocisteine | Mucoregulator — alters mucus glycoprotein composition | PO 750 mg tds initially, then 1.5 g/day | COPD with chronic bronchitis (PEACE trial); chronic bronchitis with thick secretions | Avoid in active peptic ulcer disease. Generally well-tolerated |
| Bromhexine | Traditional mucolytic — depolymerises mucopolysaccharide fibres | PO 8–16 mg tds | Chronic bronchitis, sinusitis with thickened mucus | Available OTC. Modest effect |
| Erdosteine | Mucolytic with antioxidant and anti-inflammatory properties | PO 300 mg bd | COPD with frequent exacerbations (RESTORE trial) | May be considered for COPD patients with chronic bronchitis phenotype. Patient self-funded in Australia |
| Long-term low-dose azithromycin | Macrolide — anti-inflammatory, mucoregulatory, and antimicrobial | PO 250–500 mg three times weekly | Bronchiectasis (BLESS, EMBRACE, BAT trials); CF; severe asthma (AMAZES trial); COPD with frequent exacerbations | NTM sputum screening mandatory before initiation. QTc check at baseline. Hearing assessment in long-term use |
| Ivacaftor and combination CFTR modulators (Trikafta, Symdeko, Orkambi, Kalydeco) | CFTR potentiators and correctors — restore function of defective CFTR protein | PO bd dosing per specific product | CF with eligible CFTR mutations (PBS-listed) | Profoundly improves airway physiology. Patients often demonstrate substantial reduction in sputum production |
| Isotonic saline 0.9% (nebulised) | Airway humidification | Nebulised 5 mL prn | Symptomatic relief of dry secretions where hyperosmolar therapy not tolerated | Useful stepping stone. No bronchospasm risk |
Test-dose protocol for hyperosmolar agents: record baseline FEV1, pre-treat with SABA 15 minutes prior, administer first dose under supervision, monitor for cough/wheeze/chest tightness, repeat spirometry 5–15 minutes after. A drop in FEV1 of ≥15% requires reassessment of suitability.2
References & evidence base
- Cazzola M, Page CP, Calzetta L, Matera MG. Pharmacology and therapeutics of bronchodilators. Pharmacol Rev 2012;64(3):450–504.
- Australian Medicines Handbook. Adelaide: Australian Medicines Handbook Pty Ltd, 2026.
- Elkins MR, Bye PTP. Mechanisms and applications of hypertonic saline. J R Soc Med 2011;104(Suppl 1):S2–S5.
- Wark P, McDonald VM. Nebulised hypertonic saline for cystic fibrosis. Cochrane Database Syst Rev 2018;(9):CD001506.
References are numbered in citation order (Vancouver/BMJ style) and were current at the time of writing. Guidelines are living documents — verify against the latest version before clinical use. For drug-specific detail, including full product information, consult MedsInfo.
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