May 23, 2017
Recommended Topic Related To:


"Cases of a serious birth defect of the abdominal wall called gastroschisis continues to increase over time, according to a report in CDC's Morbidity and Mortality Weekly Report. CDC researchers found that over 18 years, the prevalence of gastrosc"...



(aztreonam) For Inhalation Solution


A dose of CAYSTON consists of a 2 mL amber glass vial containing lyophilized aztreonam (75 mg) and lysine (46.7 mg), and a low-density polyethylene ampule containing 1 mL sterile diluent (0.17% sodium chloride). The reconstituted solution is for inhalation. The formulation contains no preservatives or arginine.

The active ingredient in CAYSTON is aztreonam, a monobactam antibacterial. The monobactams are structurally different from beta-lactam antibiotics (e.g., penicillins, cephalosporins, carbapenems) due to a monocyclic nucleus. This nucleus contains several side chains; sulfonic acid in the 1-position activates the nucleus, an aminothiazolyl oxime side chain in the 3-position confers specificity for aerobic Gram-negative bacteria including Pseudomonas spp., and a methyl group in the 4-position enhances beta-lactamase stability.

Aztreonam is designated chemically as (Z)-2-[[[(2-amino-4thiazolyl)[[(2S,3S)-2-methyl-4-oxo-1-sulfo-3azetidinyl]carbamoyl]methylene]amino]oxy]-2-methylpropionic acid. The structural formula is presented below:

CAYSTON® (aztreonam) Structural Formula Illustration

CAYSTON is a white to off-white powder. CAYSTON is sterile, hygroscopic, and light sensitive. Once reconstituted with the supplied diluent, the pH range is 4.5 to 6.0.

What are the possible side effects of aztreonam (Cayston)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

  • bronchospasm (wheezing, chest tightness, trouble breathing) right after using the medicine; or
  • any new or worsening symptoms.

Less serious side effects may include:

  • mild stomach discomfort, vomiting;
  • cough, sore throat;
  • stuffy nose; or
  • low fever.

This is not a complete list of...

Read All Potential Side Effects and See Pictures of Cayston »

Last reviewed on RxList: 11/8/2016
This monograph has been modified to include the generic and brand name in many instances.

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Women's Health

Find out what women really need.

Related Drugs
Use Pill Finder Find it Now See Interactions

Pill Identifier on RxList

  • quick, easy,
    pill identification

Find a Local Pharmacy

  • including 24 hour, pharmacies

Interaction Checker

  • Check potential drug interactions
Search the Medical Dictionary for Health Definitions & Medical Abbreviations