[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Monobactams](https://durgical.com/en/pharmacology/classes/monobactams/) › Aztreonam [Pharmacology](https://durgical.com/en/pharmacology/) · [Monobactams](https://durgical.com/en/pharmacology/classes/monobactams/) # Aztreonam An injectable or inhaled monobactam for aerobic gram-negative infections, useful in patients with severe allergy to other β-lactams. Updated 2026-11-01 - Class: [Monobactams](https://durgical.com/en/pharmacology/classes/monobactams/) - Enzyme: Penicillin-binding protein 3 of gram-negative bacteria - ATC code: J01DF01 ✂**Penicillin-binding protein 3 of gram-negative bacteria**Aztreonam ⓘ The figure shows aztreonam bound to penicillin-binding protein 3 of Pseudomonas aeruginosa. **Target in 3D:** Penicillin-binding protein 3 of gram-negative bacteria. PDB structure 3PBS (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/3PBS) · Drag to rotate · pinch to zoom ## Mechanism of action Aztreonam acylates penicillin-binding proteins of gram-negative bacilli (the figure shows PBP3) and blocks cell-wall synthesis, so the bacteria lyse. Its activity against Enterobacterales and Pseudomonas aeruginosa resembles that of ceftazidime; it has no useful activity against gram-positive bacteria or anaerobes. - Crosses the gram-negative outer membrane - Acylates the PBPs of gram-negative bacilli - Cell-wall synthesis stops and the bacteria lyse ## Pharmacokinetics **Absorption** Intravenous, intramuscular or inhaled. **Distribution** About half bound to serum proteins; crosses the placenta. **Elimination** Mostly unchanged in the urine. **Half-life** About 1.7 hours with normal kidney function; longer in older adults and kidney failure. ## Indications - Urinary tract infections, including pyelonephritis, by susceptible gram-negatives. [Acute pyelonephritis →](https://durgical.com/en/conditions/acute-pyelonephritis/) - Lower respiratory tract infections, including pneumonia by Pseudomonas and Enterobacterales. [Hospital-acquired and ventilator-associated pneumonia →](https://durgical.com/en/conditions/hospital-acquired-and-ventilator-associated-pneumonia/) - Septicemia by gram-negative bacilli. [Sepsis and septic shock →](https://durgical.com/en/conditions/sepsis-and-septic-shock/) - Intra-abdominal infections, including peritonitis, with an anti-anaerobe drug. [Peritonitis →](https://durgical.com/en/conditions/peritonitis/) - Inhaled, to reduce Pseudomonas exacerbations in cystic fibrosis. [Cystic fibrosis →](https://durgical.com/en/conditions/cystic-fibrosis/) ## Adverse effects ### Common - Phlebitis or discomfort at the injection site - Rash, diarrhoea, nausea ### Serious (rare, important) - Hypersensitivity reactions, including anaphylaxis (rare) - Toxic epidermal necrolysis (rare, in bone marrow transplant patients with several risk factors) - Clostridioides difficile colitis - Liver injury, especially in infants and young children ## Contraindications - Known hypersensitivity to aztreonam or any component - Caution (not absolute) in allergy to ceftazidime or other β-lactams ## Key interactions **Aminoglycosides** Synergy against Pseudomonas and other gram-negatives; kidney function and hearing are monitored because of the aminoglycoside. **Avibactam (alone or with ceftazidime)** Protects aztreonam from ESBL and KPC enzymes in metallo-β-lactamase producers. ## What is monitored - Kidney function (to adjust the regimen) - Liver tests in long courses and in children - Signs of allergy in patients with prior β-lactam reactions ## Administration and safety - IV infusion, slow IV injection or deep IM injection after reconstitution. - Inhaled aztreonam is a different product given with its own nebulizer; it is never injected. ## Nursing care - Clarify the type of previous β-lactam reaction and any ceftazidime allergy. - Watch for rash or wheeze during the first doses. - Remember gram-positive and anaerobic coverage must come from other drugs. - Teaching: report rash, diarrhoea, yellow skin or breathing problems. ## Pregnancy and breastfeeding Aztreonam crosses the placenta; animal studies showed no harm, but human data are limited, so it is used only if clearly needed. ## Memory aid AZTREONAM is a «lone ring» that only Negatives can hear: one β-lactam ring, only aerobic gram-negatives, and almost no allergy echo (except ceftaZIDime, its look-alike). ## Test yourself Think of the answer, then tap the question to see it. ## With which cephalosporin can aztreonam cross-react, and why? Ceftazidime, because the two share a similar side chain. ## An abdominal infection is treated with aztreonam alone. What coverage is missing? Anaerobes (such as Bacteroides fragilis) and gram-positives; another drug, for example metronidazole, is added. ## Why is aztreonam paired with avibactam against metallo-β-lactamase producers? Metallo-β-lactamases do not destroy aztreonam, but these bacteria often also carry ESBL or KPC, which avibactam blocks. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/aztreonam/) ## Related drugs - [Tobramycin](https://durgical.com/en/pharmacology/tobramycin/) - [Meropenem](https://durgical.com/en/pharmacology/meropenem/) - [Ceftriaxone](https://durgical.com/en/pharmacology/ceftriaxone/) ## Related conditions - [Acute pyelonephritis](https://durgical.com/en/conditions/acute-pyelonephritis/) - [Hospital-acquired and ventilator-associated pneumonia](https://durgical.com/en/conditions/hospital-acquired-and-ventilator-associated-pneumonia/) - [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/) - [Peritonitis](https://durgical.com/en/conditions/peritonitis/) - [Cystic fibrosis](https://durgical.com/en/conditions/cystic-fibrosis/) [← Back to the class: Monobactams](https://durgical.com/en/pharmacology/classes/monobactams/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [DailyMed - AZTREONAM injection, powder, lyophilized, for solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d4500795-3b07-4a7d-b432-73cafbb3dbc6) (DailyMed (U.S. National Library of Medicine), 2026); [Aztreonam Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a687010.html) (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 58 (McGraw Hill, 2023); [RCSB PDB - 3PBS: Crystal structure of PBP3 complexed with aztreonam](https://www.rcsb.org/structure/3PBS) (RCSB Protein Data Bank, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/aztreonam/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/aztreonam/