Infections
Medicines for Legionnaires' disease
A serious form of pneumonia caught by breathing in tiny water droplets containing Legionella bacteria — treated with antibiotics and prevented by proper water-system management.
Education and reference only. This explains which medicines are used and why, in plain language — it deliberately contains no doses and is not a substitute for advice from your doctor or pharmacist. Always discuss your own treatment with a qualified clinician, and check the BNF and the product labelling for prescribing detail.
Quick answer
What is Legionnaires' disease?
Legionnaires' disease is a serious lung infection (a type of pneumonia) caused by Legionella bacteria. People catch it by breathing in tiny droplets of water containing the bacteria — for example from contaminated air-conditioning systems, hot tubs, showers, spa pools or other water systems where the bacteria have been able to grow.
- How it is treated: Legionnaires' disease is treated with antibiotics that are effective against Legionella, and many people need hospital care, especially if the pneumonia is severe or they have other health problems; supportive care includes oxygen and fluids as needed.
- Self-care: Prevention rests mainly on proper management and maintenance of water systems (a responsibility for building and facility managers).
- When to seek help: See a doctor promptly for a cough, high fever, breathlessness and muscle aches, especially after using a hot tub, spa or staying somewhere with air conditioning.
What it is
Legionnaires' disease is a serious lung infection (a type of pneumonia) caused by Legionella bacteria. People catch it by breathing in tiny droplets of water containing the bacteria — for example from contaminated air-conditioning systems, hot tubs, showers, spa pools or other water systems where the bacteria have been able to grow. It is not usually spread from person to person. Symptoms come on over days and can include a cough, breathlessness, high fever, muscle aches, headache, and sometimes tummy upset and confusion. It is more likely to cause severe illness in older people, smokers, and those with weakened immunity or existing lung conditions. Because it can be serious, it is important to diagnose and treat promptly; it is confirmed with tests including a urine test and chest imaging.
How it is treated
Legionnaires' disease is treated with antibiotics that are effective against Legionella, and many people need hospital care, especially if the pneumonia is severe or they have other health problems; supportive care includes oxygen and fluids as needed. Most people recover with prompt treatment, though recovery can take time and severe cases can be life-threatening. Prevention focuses on managing water systems to stop the bacteria growing — through proper design, temperature control, cleaning and maintenance of things like cooling towers, hot and cold water systems and spa pools — which is a legal responsibility for those managing such systems. Cases and outbreaks are investigated by public health teams to find and control the source.
For this condition, these medicines
Medicine classes used for Legionnaires' disease
Each links to a full, dose-free guide — what it is, how it works, who can and cannot use it, side effects, interactions and FAQs.
Beyond medication
Lifestyle and self-care
Prevention rests mainly on proper management and maintenance of water systems (a responsibility for building and facility managers). Not smoking supports lung health. There are no specific personal precautions for most people beyond well-maintained water systems.
When to get help
When to see a doctor
See a doctor promptly for a cough, high fever, breathlessness and muscle aches, especially after using a hot tub, spa or staying somewhere with air conditioning. Seek urgent care for severe breathlessness, confusion, or being very unwell.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
Answers
Legionnaires' disease: frequently asked questions
How do you catch Legionnaires' disease?
By breathing in tiny droplets of water containing Legionella bacteria — for example from contaminated air conditioning, hot tubs, spa pools or water systems. It is not usually spread from person to person.
Is Legionnaires' disease treatable?
Yes — it is treated with antibiotics, and most people recover with prompt treatment, though many need hospital care and severe cases can be serious. Preventing it relies on proper water-system management.
Sources
Where this is drawn from
- NHS — Legionnaires' disease
- HSE / UKHSA — Legionella guidance
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