Aztreonam: uses, dosing, side effects & brands
Aztreonam is a medicine sold in the U.S. under 3 brand and generic names, for cellulitis, endometritis and pseudomonas infections. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Treats (across its forms)
- Cellulitis, Endometritis and Pseudomonas Infections
- Available as
- Injectable · Kit
- Sold as
- 3 products — Azactam in Plastic Container, Cayston and Azactam
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
Get treated for Aztreonam conditions online
Licensed online providers — consult & get prescribed if eligible.
Advertising disclosure: We may earn a commission, at no extra cost to you. This never affects our ratings. Details
How Cayston is dosed
From the FDA label for Cayston (application NDA050814). Other aztreonam products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Administer one dose (one single use vial and one ampule of diluent) 3 times a day for 28 days. ( 2.1 ) Use dose immediately after reconstitution. ( 2.2 ) Administer only with the Altera ® Nebulizer System. Do not administer with any other type of nebulizer. ( 2.3 ) 2.1 Dosing Information The recommended dose of CAYSTON for both adults and pediatric patients 7 years of age and older is one single-use vial (75 mg of aztreonam) reconstituted with 1 mL of sterile diluent administered 3 times a day for a 28-day course (followed by 28 days off CAYSTON therapy). Dosage is not based on weight or adjusted for age. Doses should be taken at least 4 hours apart. CAYSTON is administered by inhalation using an Altera ® Nebulizer System. Patients should use a bronchodilator before administration of CAYSTON. 2.2 Instructions for CAYSTON Reconstitution CAYSTON should be administered immediately after reconstitution. Do not reconstitute CAYSTON until ready to administer a dose. Take one amber glass vial containing CAYSTON and one diluent ampule from the carton. To open the glass vial, carefully remove the blue cap and metal ring and remove the gray rubber stopper. Twist the tip off the diluent ampule and squeeze the liquid into the glass vial. Replace the rubber stopper, then gently swirl the vial until contents have completely dissolved. The empty vial, stopper, and diluent ampule should be…
Everything below is the FDA label for Cayston (kit). Aztreonam is also sold as injectable, and those are different medicines to take — follow the label for the one you were prescribed.
Cayston side effects
Common adverse reactions (more than 5%) occurring more frequently in CAYSTON patients are cough, nasal congestion, wheezing, pharyngolaryngeal pain, pyrexia, chest discomfort, abdominal pain and vomiting. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Gilead Sciences, Inc. at 1-800-GILEAD5, option 3 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of drugs cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of CAYSTON was evaluated in 344 patients from two placebo-controlled trials and one open-label follow-on trial. In controlled trials, 146 patients with CF received 75 mg CAYSTON 3 times a day for 28 days. Table 1 displays adverse reactions reported in more than 5% of patients treated with CAYSTON 3 times a day in placebo-controlled trials. The listed adverse reactions occurred more frequently in CAYSTON-treated patients than in placebo-treated patients. Table 1 Adverse Reactions Reported in more than 5% of Patients Treated with CAYSTON in the Placebo-Controlled Trials Event (Preferred Term) Placebo (N=160) n (%) CAYSTON 75 mg 3 times a day (N=146) n (%) Cough 82 (51%) 79 (54%) Nasal congestion 19 (12%) 23 (16%) Wheezing 16…
Who shouldn’t take Cayston
CAYSTON is contraindicated in patients with a known allergy to aztreonam. Contraindicated in patients with a known allergy to aztreonam. ( 4 )
Cayston drug interactions
No formal clinical studies of drug interactions with CAYSTON have been conducted.
Every aztreonam product we track (3)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | 72/100 | Prescription | Injectable | No data | — | View → | |
| 2 | 70/100 | Prescription | Kit | No data | — | View → | |
| 3 | Not yet rated | Prescription | Injectable | No data | — | View → |
Combination products containing aztreonam
A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.
Aztreonam and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for aztreonam: levels in milk, effects in breastfed infants, and the drugs it would consider insteadLimited information indicates that aztreonam produces low levels in milk that are not expected to cause adverse effects in breastfed infants. Occasionally disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush, have been reported with beta-lactams, but these effects have not been adequately evaluated. A task force respiratory experts from Europe, Australia and New Zealand found that aztreonam is compatible with breastfeeding. Aztreonam is acceptable in nursing mothers.
National Institute of Child Health and Human Development, record revised March 15, 2025. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about aztreonam
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 14,513 reports naming aztreonam, and the FDA flagged 96% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- cystic fibrosis2,869 reports
- pneumonia1,341 reports
- infection868 reports
- lung disorder570 reports
- dyspnoea540 reports
- lung transplant512 reports
- infective pulmonary exacerbation of cystic fibrosis481 reports
- cystic fibrosis respiratory infection suppression452 reports
Read these as a signal, not a rate. A report does not mean aztreonam caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved August 25, 2026.
Related calculators
Frequently asked questions
What is Cayston?
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.
Can you take aztreonam with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run aztreonam against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is aztreonam sold under?
We track 3 aztreonam-containing products in the U.S.: Azactam in Plastic Container, Cayston and Azactam. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does aztreonam come in?
Across the brands we track, aztreonam is currently marketed as injectable and kit, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic aztreonam?
We do not currently list a generic-labelled aztreonam product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Aztreonam: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/aztreonam
- MLA
- “Aztreonam: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/aztreonam.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for aztreonam on DailyMed (NIH) ↗.