Antibiotics and cystic fibrosis: What you need to know

Last updated Sept. 11, 2025, by Agata Boxe
Fact-checked by Inês Martins, PhD

Antibiotics play a crucial role in managing cystic fibrosis (CF), a condition that causes thick, sticky mucus to build up in various organs, including the lungs. This mucus provides a fertile breeding ground for chronic bacterial infections.

While highly effective CF treatments are now available, bacterial infections remain common, and many people require long-term treatment with antibiotics to manage them.

Understanding how antibiotics help, their potential risks, and their role in long-term care is essential for people with CF and their caregivers.

The role of antibiotics in CF

CF makes you susceptible to bacterial infections, which may lead to inflammation and lung damage over time. Antibiotics can help to prevent complications by either killing the bacteria or slowing their growth.

The medications can be used:

short-term to treat acute infections
long-term for chronic infections
prophylactically to prevent infections

Types of antibiotics used in CF

Three main types of antibiotics can be prescribed for CF: oral, intravenous (into-the-vein), and inhaled. Your doctor can help determine whether you need antibiotics, and if so, which type.

Oral antibiotics

Oral antibiotics for CF can be prescribed as tablets, capsules, or liquids. They can be used for both chronic infections and mild worsening of respiratory symptoms.

The exact frequency and duration of use vary depending on the antibiotic. For example, while some are taken once a day for a few days, others are taken for more extended periods. Some may need to be taken with food, while others are taken on an empty stomach.

If your CF team determines that you need an oral antibiotic, they will select the most appropriate type and provide instructions on how to take it.

Intravenous antibiotics

Intravenous antibiotics are medications that are delivered directly into the bloodstream.

They can be used to treat infections that cannot be treated with oral antibiotics or that have not responded to them. One scenario in which they are needed is if you have a severe respiratory exacerbation, which is characterized by a flare-up of lung symptoms, such as increased coughing, changes in mucus production, or breathing difficulties.

A healthcare professional usually delivers intravenous antibiotics at a hospital through a catheter inserted into the arm. Your doctor may also recommend using them at home, and if they do, a trained professional can teach you how to administer them in this setting.

Inhaled antibiotics

Inhaled antibiotics are delivered through the airways directly into your lungs using an external device.

Your CF doctor will first do a test — a sputum culture — that can detect and identify bacteria in mucus from the lungs to see if you need to take this type of antibiotic.

Inhaled antibiotics are typically administered with a nebulizer, a device that converts liquid medicine into a fine mist that can be inhaled.

Your doctor can show you how to use the nebulizer correctly. Usually, the medication is placed in a clean nebulizer cup and attached to an air compressor. The compressor blows air through the cup, creating a mist that you breathe in through a mouthpiece.

Potential risks

By fighting bacteria that can cause infections, antibiotics can help reduce coughing, mucus, and breathing issues. But like many other medications, taking them comes with certain risks.

For example, you may experience side effects that may vary depending on the type of antibiotic you are using, including:

gastrointestinal issues such as upset stomach, diarrhea, and nausea
fungal infections
headaches
rash

Another possible issue is antibiotic resistance, which occurs when bacteria change when exposed to antibiotics in ways that allow them to survive those medications, so they will no longer be helpful. As a result, higher doses of the same antibiotic or different antibiotics are needed to manage or prevent bacterial infections in CF.

Communicating with your care team

Due to the potential risks associated with taking antibiotics, it is essential to communicate regularly with your CF care team.

Don’t be afraid to ask questions about the antibiotics you may be prescribed, such as:

How are they administered?
How long do they have to be taken?
Do they have any side effects?
How long do the side effects last?

Tell your doctor if you experience any potential side effects while taking an antibiotic or if you feel it is not working as well as it should. They can help you find ways to manage any issues or may choose to modify your treatment plan.

Antibiotics are an essential part of CF treatment, as they can help prevent and manage infections and improve your quality of life. Knowing their benefits and risks can help you and your care team make informed decisions about managing CF.

Cystic Fibrosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.