Skip to main content


Why is it prescribed?

Aztreonam is an inhaled antibiotic used to treat P. aeruginosa lung infections in people with Cystic Fibrosis

Products that have this ingredient include •Cayston® •

See other drugs used in the treatment of •cystic fibrosis •

The most common side effects are:

  • cough
  • nasal congestion
  • wheezing
  • sore throat
  • fever
  • chest discomfort
  • runny nose

Contact your doctor if:

  • you develop a rash - this could mean that you have an allergic reaction to aztreonam
  • you have difficulty breathing (bronchospasm) immediately after inhalation.  Bronchospasm is a potential side effect with inhalation therapies such as this.

When aztreonam is inhaled, it enters the lungs and come in contact with the P. aeruginosa bacteria that are present. It binds to certain P. aeruginosa proteins and interferes with the development of the bacterial cell wall causing the cell wall to break and killing the bacteria. By decreasing the number of P. aeruginosa bacteria living in the lungs, lung infection is reduced and respiratory symptoms and lung function are improved.

Do not use aztreonam:

  • if you are allergic to aztreonam or any components of this medication

Use aztreonam with caution:

  • if you have kidney or liver disease

Drug Interactions:

  • No known interactions

Safety in Pregnancy: Studies in animals suggest low risk in pregnancy but no human data available.

Safety in Breastfeeding: Use is likely safe if breastfeeding.