Long-term infection suppression in selected adults with bronchiectasis
Nebulised Antibiotics in Non-CF Bronchiectasis
Nebulised antibiotics deliver antimicrobial treatment directly into the airways. They may be considered for selected adults with non-cystic fibrosis bronchiectasis, particularly those with chronic Pseudomonas aeruginosa infection and frequent exacerbations despite optimised bronchiectasis care.
- Chronic Pseudomonas infection
- Colistimethate
- Gentamicin
- Other inhaled antibiotics
- Nebuliser trial
- Airway clearance
- Adverse effects
- Treatment monitoring
Not every positive sputum culture needs nebulised treatment
The decision depends on the organism, repeated cultures, exacerbation burden, symptoms, previous treatment, airway clearance and the individual balance of benefit and treatment burden.
The aim is suppression, not guaranteed eradication
In established chronic infection, long-term inhaled treatment usually aims to reduce bacterial burden and exacerbations rather than promise permanent clearance of the organism.
What are nebulised antibiotics?
Nebulised antibiotics are liquid antimicrobial medicines converted into a fine aerosol by a compatible nebuliser. The patient inhales the aerosol so that a high concentration of the antibiotic reaches the infected airways.
Bronchiectasis causes permanent widening and damage of the airways. Mucus can collect within these airways, allowing bacteria to persist and contributing to repeated bronchiectasis exacerbations .
Delivering an antibiotic directly to the lungs can create a high local drug concentration while usually producing less systemic exposure than the same medicine given intravenously. This does not mean the treatment is free from systemic effects or monitoring requirements.
Direct airway delivery
The aerosol carries the antibiotic into the bronchial tree, where chronically infecting bacteria are located.
High local concentration
Inhaled delivery can achieve airway concentrations that would be difficult to obtain safely with prolonged systemic therapy.
Lower systemic exposure
Absorption into the bloodstream is generally lower than with intravenous treatment, although kidney, hearing and balance risks may still matter for some antibiotics.
Long-term suppressive role
Treatment is often used regularly over months or longer to reduce infection activity and future exacerbation risk.
Nebulised antibiotics do not replace airway clearance, sputum monitoring, vaccination, exercise, treatment of underlying causes or prompt management of acute exacerbations.
Who may benefit from a long-term inhaled antibiotic?
Current guidelines place the strongest emphasis on people with chronic Pseudomonas aeruginosa infection who remain at high risk of exacerbations despite appropriate standard care.
Repeated Pseudomonas cultures
The organism has been isolated repeatedly from sputum, making transient contamination less likely.
Frequent exacerbations
The patient continues to require repeated antibiotic courses, commonly three or more exacerbation treatments in a year.
Severe exacerbation risk
Hospital admission, intravenous antibiotics or particularly disruptive exacerbations may justify treatment at a lower numerical frequency.
Persistent daily symptoms
Chronic purulent sputum, cough, breathlessness or impaired quality of life may add to the case for suppressive treatment.
Optimised airway clearance
Respiratory physiotherapy has been reviewed and the patient is completing a suitable airway-clearance routine.
Suitable organism and sensitivity
The sputum organism and its susceptibility pattern support the proposed inhaled antibiotic.
Treatment is not based on the sputum result alone
Some people have chronic bacterial isolation but relatively few exacerbations and manageable symptoms. The likely clinical benefit must be weighed against bronchospasm, resistance, treatment time, device cleaning and long-term adherence.
Why is Pseudomonas aeruginosa important?
Pseudomonas aeruginosa is a Gram-negative bacterium that can persist within damaged bronchiectatic airways. Chronic infection is associated with a greater burden of exacerbations, hospitalisation and disease severity in many patients.
It can form biofilms
Bacteria within biofilms are protected by a structured matrix, making complete clearance more difficult.
It can adapt over time
Pseudomonas may change its appearance and antibiotic susceptibility during chronic airway infection.
It can drive inflammation
Persistent bacterial products stimulate airway inflammation, contributing to mucus production and further injury.
It requires repeated monitoring
Sputum cultures help identify persistence, new resistance and additional organisms.
New isolation is different from established chronic infection
A newly detected Pseudomonas isolate may prompt an eradication strategy intended to prevent chronic infection. This is different from long-term suppressive therapy for an organism already established in the airways.
What should be checked before treatment starts?
- Confirm the bronchiectasis diagnosis High-resolution CT imaging and the clinical history should support a diagnosis of clinically significant bronchiectasis.
- Review repeated sputum microbiology The specialist reviews the organism, frequency of isolation and antibiotic susceptibility results.
- Record the exacerbation history Antibiotic courses, hospital admissions, intravenous treatment and recovery time during the previous year are documented.
- Optimise airway clearance A respiratory physiotherapist should review technique, frequency, positioning and any airway-clearance device.
- Assess baseline lung function Spirometry provides a comparison for the supervised first-dose trial and future monitoring.
- Review kidney function Renal impairment can increase systemic toxicity from certain antibiotics even when treatment is inhaled.
- Ask about hearing and balance Baseline symptoms and previous aminoglycoside exposure are relevant when gentamicin or tobramycin is considered.
- Exclude relevant NTM disease Sputum testing for nontuberculous mycobacteria may be needed, particularly when the clinical or radiological pattern is suggestive.
- Review allergies and previous reactions The intended drug, preservatives and related antibiotic classes must be considered.
- Discuss treatment burden The patient should understand preparation, inhalation, cleaning, storage and the likely duration of treatment.
Learn more about airway-clearance treatment in bronchiectasis .
Why is the first dose usually supervised?
Nebulised antibiotics can irritate the airways and cause acute bronchoconstriction. The first dose is therefore commonly given as a supervised nebuliser challenge or tolerance test.
The exact protocol varies between specialist centres. It may be led by a respiratory physiotherapist, respiratory nurse or another trained clinician.
Before the dose
Symptom check
The clinician asks about wheeze, chest tightness, breathlessness, infection and recent inhaler use.
Baseline observations
Oxygen saturation and other observations may be recorded according to the patient’s condition.
Baseline spirometry
FEV1 and other measurements establish the patient’s starting airflow.
During the treatment
Device instruction
The patient learns how to assemble, position and use the prescribed nebuliser system.
Breathing technique
Relaxed tidal breathing is generally used unless the specific device requires a different manoeuvre.
Symptom monitoring
Cough, chest tightness, wheeze, dizziness and breathing difficulty are monitored.
After the treatment
Repeat lung function
Spirometry may be repeated to identify a clinically important fall in airflow.
Assess tolerability
The team decides whether the reaction is acceptable, requires bronchodilator pre-treatment or prevents use.
Home-care education
Cleaning, drying, storage, dose preparation and safe disposal are reviewed before home treatment begins.
A bronchodilator may be prescribed before the antibiotic
Some patients are advised to use a bronchodilator before nebulisation to reduce airway narrowing. This should follow the individual plan issued by the clinical team rather than being added independently.
Which nebulised antibiotics are used?
The antibiotic is selected according to the sputum organism, susceptibility pattern, previous tolerance, clinical evidence, device availability and local specialist pathways.
| Antibiotic | Potential role | Important considerations |
|---|---|---|
| Colistimethate sodium | Guideline-preferred long-term inhaled option in the UK for chronic Pseudomonas infection with frequent exacerbations | Cough, chest tightness and bronchospasm can occur; products and nebuliser systems are not automatically interchangeable |
| Gentamicin | Guideline-supported alternative when colistimethate is unsuitable, ineffective or not tolerated | Requires consideration of hearing, balance, kidney function, previous aminoglycoside exposure and bronchospasm |
| Tobramycin | May be considered by a specialist team for selected Pseudomonas infections | Evidence in non-CF bronchiectasis is mixed; voice change, cough, bronchospasm and aminoglycoside toxicity require attention |
| Aztreonam lysine | Licensed for chronic Pseudomonas infection in cystic fibrosis but not routinely recommended for non-CF bronchiectasis | Trials in non-CF bronchiectasis did not establish consistent clinical benefit and respiratory adverse effects may occur |
| Nebulised meropenem | Occasionally used as an individualised specialist or microbiology-led option for resistant organisms | Off-label with limited evidence; preparation, stability, device compatibility and allergy risk require specialist oversight |
| Other inhaled formulations | Investigational, trial-based or available through selected specialist pathways | Availability, licensing, dosing schedules and evidence differ between countries and products |
Do not copy doses from another inhaled product
Different brands, formulations and devices may contain different quantities, concentrations and delivery characteristics. A dry powder product is not equivalent to a nebulised solution. Use only the medicine, diluent, dose and device specified by the prescribing specialist and pharmacy.
Colistimethate sodium
Colistimethate sodium, often referred to as nebulised colistin and supplied under several product names, is commonly used for chronic Pseudomonas aeruginosa infection in non-CF bronchiectasis.
It belongs to the polymyxin group of antibiotics and damages the outer membrane of susceptible Gram-negative bacteria. In UK bronchiectasis guidance it is the preferred long-term inhaled antibiotic for suitable patients with chronic Pseudomonas infection and a high exacerbation burden.
Formulation matters
Different colistimethate products may use different unit descriptions, diluents and preparation instructions.
Device compatibility matters
A standard jet, vibrating-mesh or adaptive aerosol device may deliver the medicine differently and must be approved for the prescribed preparation.
Reconstitution must be correct
The medicine should be mixed only with the prescribed diluent and used within the advised period.
Tolerance varies
Some patients tolerate colistimethate well, while others develop cough, throat irritation or bronchospasm.
Colistimethate doses can be described in different units
Prescriptions may use international units, million units or milligrams depending on the preparation. These measurements must not be converted casually. Follow the labelled product and specialist pharmacy instructions exactly.
Nebulised gentamicin
Gentamicin is an aminoglycoside antibiotic active against many Gram-negative organisms, including susceptible strains of Pseudomonas aeruginosa. It may be considered when colistimethate is inappropriate or not tolerated.
Sputum-directed selection
The cultured organism and susceptibility pattern should support gentamicin use.
Hearing and balance review
Tinnitus, hearing loss, dizziness and balance problems should be discussed before and during treatment.
Kidney-function review
Significant renal impairment can increase systemic aminoglycoside exposure and toxicity risk.
Airway tolerability
Cough, throat irritation, wheeze or bronchospasm may require modification or discontinuation.
Aminoglycoside toxicity remains relevant with inhaled treatment
Systemic absorption is lower than with intravenous therapy but is not necessarily zero. Report new tinnitus, hearing change, vertigo, imbalance or reduced urine output promptly.
Tobramycin, aztreonam and nebulised meropenem
These antibiotics appear in studies, cystic-fibrosis pathways or individual specialist practice, but they should not be presented as routine equivalent alternatives for every patient with non-CF bronchiectasis.
Tobramycin
Drug class
Tobramycin is an aminoglycoside with activity against susceptible Gram-negative bacteria.
Possible use
A bronchiectasis specialist may consider it in selected chronic Pseudomonas infections.
Cautions
Dysphonia, cough, bronchospasm, tinnitus, hearing change and renal risk require review.
Aztreonam lysine
Drug class
Aztreonam is a monobactam antibiotic directed mainly against Gram-negative bacteria.
Evidence
Trials in non-CF bronchiectasis did not show sufficiently consistent benefit for routine use.
Current role
It is not a standard first-line long-term inhaled antibiotic for non-CF bronchiectasis in UK guidance.
Nebulised meropenem
Drug class
Meropenem is a broad-spectrum carbapenem normally used intravenously for serious bacterial infections.
Possible specialist use
Nebulisation is an off-label, individualised approach that may be considered for selected resistant infections.
Limitations
Evidence, formulation stability, compatibility and optimal dosing are less established than for guideline-preferred options.
What is the usual treatment order?
The exact sequence is personalised, but airway clearance should usually occur before the antibiotic so that mucus does not block delivery to the bronchial walls.
- Use a prescribed bronchodilator when advised This may help open the airways and reduce bronchospasm from subsequent nebulised treatments.
- Use nebulised saline or another mucoactive treatment Where prescribed, this can help loosen thick sputum before airway clearance.
- Complete airway clearance Perform the technique advised by the respiratory physiotherapist and clear as much sputum as comfortably possible.
- Nebulise the antibiotic Use the prescribed medicine, dose, nebuliser chamber and breathing technique.
- Rinse the mouth when advised This may reduce unpleasant taste, throat irritation and local residue.
- Clean and dry the equipment Follow the manufacturer and clinical-team instructions after every treatment.
The antibiotic should usually come after airway clearance
Performing vigorous airway clearance immediately after the antibiotic may remove some of the deposited medicine. Follow the sequence issued by the respiratory physiotherapist because individual regimens can differ.
Nebuliser selection, cleaning and infection control
Drug delivery can vary considerably between nebuliser systems. The device should therefore be selected for the prescribed medicine rather than chosen solely for speed or convenience.
Use the prescribed device
Jet, vibrating-mesh and adaptive aerosol systems do not necessarily produce identical drug delivery.
Clean after each use
Medication residue and respiratory secretions should not be allowed to accumulate in the chamber.
Dry components completely
Persistent moisture can encourage microbial contamination.
Replace components as advised
Chambers, tubing, filters or mesh components may require scheduled replacement.
Do not share equipment
Nebuliser chambers and mouthpieces are intended for one patient unless a validated clinical decontamination process applies.
Ventilate the treatment area
Exhaled aerosol and escaped antibiotic should be minimised, particularly around other people and pets.
Do not immerse electrical components
Only washable parts should be cleaned or disinfected. Follow the exact manufacturer instructions for the compressor, controller, handset, mesh and tubing.
What side effects can nebulised antibiotics cause?
Cough
Aerosol deposition can provoke coughing during or shortly after treatment.
Bronchospasm
Wheeze, chest tightness and a measurable fall in airflow may occur, particularly during the first doses.
Throat irritation
Dryness, soreness, an unpleasant taste or hoarseness can develop.
Voice change
Dysphonia is reported with some inhaled antibiotic formulations.
Hearing or balance effects
Aminoglycosides can rarely affect hearing or the vestibular system, particularly where systemic absorption is increased.
Kidney effects
Renal toxicity is less common than with systemic treatment but remains relevant with aminoglycosides and polymyxins.
Allergy
Rash, swelling, marked wheeze or another hypersensitivity reaction can occur.
Resistant organisms
Long-term exposure can alter bacterial susceptibility and the respiratory microbiome.
Report persistent side effects rather than simply stopping
The clinical team may review bronchodilator pre-treatment, technique, nebuliser choice, dose timing or an alternative antibiotic. Severe breathing difficulty or suspected allergy requires urgent assessment.
How is treatment monitored?
Continued treatment should have a defined clinical purpose and be reviewed regularly. Merely tolerating the nebuliser is not enough; the team should assess whether it is reducing the burden of disease.
| Monitoring area | What may be reviewed | Why it matters |
|---|---|---|
| Exacerbations | Number, severity, antibiotic use, hospital admission and recovery time | A major aim is to reduce clinically important exacerbations |
| Daily symptoms | Cough, sputum volume, sputum colour, breathlessness and fatigue | Treatment may improve symptoms even when bacteria remain detectable |
| Sputum cultures | Persistent organism, bacterial density, new pathogens and antibiotic susceptibility | Identifies microbiological change and potential resistance |
| Lung function | Spirometry and other tests where clinically indicated | Tracks airway stability and helps investigate deterioration |
| Tolerability | Bronchospasm, cough, voice change, throat irritation and treatment time | Persistent adverse effects undermine adherence and benefit |
| Kidney function | Blood tests according to the drug, comorbidities and other nephrotoxic medicines | Detects increased systemic toxicity risk |
| Hearing and balance | Symptoms and formal audiology where appropriate | Important with aminoglycoside exposure |
| Treatment burden | Time, cleaning, missed doses, travel and effect on daily life | A theoretically effective regimen will fail when it is not realistically sustainable |
Long-term antibiotic treatment should be reviewed regularly by a bronchiectasis specialist, with earlier assessment when exacerbations continue, side effects develop or sputum microbiology changes.
What happens during an acute exacerbation?
A long-term nebulised antibiotic does not necessarily provide adequate treatment for an acute exacerbation. Additional oral or intravenous antibiotics may be needed according to symptoms, severity and recent sputum results.
Do not double the nebulised dose
Follow the written bronchiectasis action plan and contact the treating team. The specialist will advise whether the nebulised antibiotic should continue, pause or be changed while systemic treatment is given.
Submit a sputum sample before starting additional antibiotics when possible and when this does not delay necessary treatment.
What benefits can patients realistically expect?
Fewer exacerbations
The principal expected benefit is a reduction in future exacerbation frequency or severity.
Reduced bacterial burden
Sputum bacterial density may fall even when cultures do not become permanently negative.
Improved symptoms
Some patients report less sputum, cough or chest congestion.
Improved quality of life
Fewer infections may mean less disruption, time away from work and anxiety about hospital treatment.
Lung function may not improve
A useful reduction in exacerbations can occur without a large increase in spirometry. The treatment should be judged across several outcomes rather than one lung-function number.
When should urgent medical advice be sought?
Stop the treatment and seek urgent advice for:
- severe or rapidly worsening wheeze;
- marked chest tightness or breathing difficulty;
- swelling of the lips, tongue, face or throat;
- a widespread rash with breathing symptoms;
- fainting, collapse or severe dizziness;
- new significant hearing loss or severe vertigo;
- coughing a substantial amount of blood;
- severe chest pain or blue or grey lips.
Call 999 for severe breathing difficulty, facial or throat swelling, collapse, blue or grey lips, heavy haemoptysis or another immediately life-threatening symptom.
Conclusion
Nebulised antibiotics deliver antimicrobial treatment directly into the bronchiectatic airways. Their most clearly supported role is long-term treatment of selected adults with chronic Pseudomonas aeruginosa infection who remain at high risk of exacerbations.
UK guidance generally favours inhaled colistimethate, with inhaled gentamicin as an alternative. Tobramycin may be considered in selected circumstances, while aztreonam and nebulised meropenem are not routine interchangeable first-line options for non-CF bronchiectasis.
Before treatment, the specialist should review sputum microbiology, exacerbations, airway clearance, lung function, kidney function, hearing, balance, allergies and treatment burden.
A supervised first-dose trial helps identify bronchospasm and allows the patient to learn correct nebuliser technique. The prescribed formulation, diluent, dose and device must be followed exactly.
Ongoing care should include sputum cultures, clinical review, monitoring for toxicity and an assessment of whether treatment is genuinely reducing exacerbations and improving daily life.
Patients with recurrent infections or chronic Pseudomonas should receive a comprehensive specialist bronchiectasis assessment rather than nebulised antibiotics being considered in isolation.
Frequently asked questions
Are nebulised antibiotics used for every person with bronchiectasis?
No. They are mainly considered for selected patients with chronic bacterial infection, particularly Pseudomonas, and a continuing high exacerbation risk despite optimised care.
Which inhaled antibiotic is usually used first?
UK bronchiectasis guidance generally recommends inhaled colistimethate for chronic Pseudomonas infection, with gentamicin as an alternative when appropriate.
Will nebulised antibiotics eradicate Pseudomonas permanently?
Not usually once chronic infection is established. Long-term treatment generally aims to suppress bacterial burden and reduce exacerbations.
Why must the first dose be supervised?
Inhaled antibiotics can cause bronchospasm. A supervised trial allows symptoms and lung function to be checked before and after treatment.
Should I use my airway-clearance treatment first?
Usually yes. Clearing mucus before the antibiotic can improve drug access to the airway surface. Follow the precise order given by your respiratory physiotherapist.
Can I use any nebuliser with my antibiotic?
No. Drug delivery varies between devices. Use only the nebuliser system approved for the prescribed formulation by the specialist service.
Can I mix saline and antibiotics in the same chamber?
Not unless the prescribing team and pharmacy have specifically confirmed compatibility. Mixing medicines can alter stability and delivered dose.
Is inhaled colistimethate the same as intravenous colistin?
The active antibiotic family is related, but formulations, preparation, dose units and routes are not interchangeable. Use only the prescribed inhaled product.
Can nebulised gentamicin affect hearing?
Systemic absorption is usually limited, but aminoglycosides can affect hearing or balance. Report tinnitus, hearing change, dizziness or imbalance promptly.
Is tobramycin routinely used for non-CF bronchiectasis?
It may be considered by specialist teams in selected cases, but it is not automatically the preferred first-line inhaled antibiotic for non-CF bronchiectasis in UK guidance.
Is nebulised aztreonam recommended routinely?
No. Evidence in non-CF bronchiectasis has not shown sufficiently consistent clinical benefit for routine use.
What should I do if I wheeze during treatment?
Stop the nebuliser and follow the plan issued by your clinical team. Severe or rapidly worsening breathing difficulty requires urgent medical help.
Should I continue the nebulised antibiotic during an exacerbation?
Follow your individual action plan. Some regimens continue, while others are paused during additional oral or intravenous antibiotic treatment.
How long is nebulised antibiotic treatment continued?
It may continue for months or longer when effective and tolerated. Regular specialist review should confirm continuing benefit and safety.
References and further information
- European Respiratory Society. European Respiratory Society clinical practice guideline for the management of adult bronchiectasis. 2025. Visit ERS Publications
- British Thoracic Society. BTS guideline for bronchiectasis in adults. View the BTS bronchiectasis guideline
- National Institute for Health and Care Excellence. Bronchiectasis (non-cystic fibrosis), acute exacerbation: antimicrobial prescribing. NICE guideline NG117. View the NICE guideline
- Shteinberg M, et al. Prescribing preferences and availability of nebulisers and inhalers for inhaled medications in bronchiectasis. ERJ Open Research. 2024. Visit ERJ Open Research
- London Chest Specialist. Bronchiectasis diagnosis and treatment. Read about specialist bronchiectasis care
- London Chest Specialist. Airway clearance in bronchiectasis. Read about airway-clearance treatment
- London Chest Specialist. Lung-function tests. Read about respiratory diagnostic testing
