Aztreonam
AZACTAM
What it isMonobactam inhibiting penicillin-binding proteins; Gram-negative and pseudomonal infection.
Why this oneNo cross-reactivity with penicillins or cephalosporins, so it is the beta-lactam for severe beta-lactam allergy.
What limits itNo Gram-positive or anaerobic cover at all. Ceftazidime shares its side chain, which is the one cross-reaction to remember.
FDA-approved for
- gram-negative infections (1986)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Urinary tract infections (complicated and uncomplicated) | Adult | 500 mg or 1 g IV/IM q8h or q12h | Per severity/susceptibility | 8 g/day |
| Moderately severe systemic infections (pneumonia, septicemia, intra-abdominal, gynecologic, skin-structure) | Adult | 1 g or 2 g IV/IM q8h or q12h | Per severity/susceptibility | 8 g/day |
| Severe systemic or life-threatening infections (incl. P. aeruginosa) | Adult | 2 g IV q6h or q8h | 2 g q6-8h at least on initiation for P. aeruginosa | 8 g/day |
| Mild-moderate infections | Peds 9 mo-16 yr (normal renal function) | 30 mg/kg IV q8h | 30 mg/kg q8h | 120 mg/kg/day |
| Moderate-severe infections | Peds 9 mo-16 yr (normal renal function) | 30 mg/kg IV q6h or q8h | 30 mg/kg q6-8h; higher doses may be warranted in cystic fibrosis | 120 mg/kg/day |
Renal CLcr 10-30 mL/min/1.73 m2: usual loading dose (1-2 g) then halve dose; CLcr <10 (incl. HD): usual initial dose (500 mg-2 g) then 1/4 of initial dose at usual q6-12h interval; serious infections: add 1/8 of initial dose after each hemodialysis
Hepatic Undefined (appropriate monitoring recommended in impaired hepatic function; no dose adjustment specified)
Max 8 g/day (adults); 120 mg/kg/day (peds)
Instructions
- IV route recommended for single doses >1 g and for septicemia, abscess, peritonitis, or other severe systemic/life-threatening infections
- Continue ≥48 h after patient becomes asymptomatic or evidence of eradication; persistent infections may need several weeks
- Do not use doses smaller than indicated
- Pediatric: administer intravenously (insufficient IM data)
- Elderly: estimate creatinine clearance and adjust dosage accordingly
Cautions
- Hypersensitivity reactions can occur with or without prior exposure; use caution with history of beta-lactam allergy (cross-reactivity rare); discontinue and treat if allergic reaction occurs
- C. difficile-associated diarrhea (mild to fatal colitis)
- Rare toxic epidermal necrolysis (bone marrow transplant patients with multiple risk factors)
- Monitor renal function with concurrent aminoglycosides (nephro-/ototoxicity)
- Superinfection with nonsusceptible organisms (Gram-positives, fungi)
Adverse reactions
- Local: phlebitis/thrombophlebitis (IV ~1.9%), injection-site discomfort/swelling (IM ~2.4%)
- Diarrhea, nausea/vomiting, rash (1-1.3%)
- <1%: anaphylaxis, angioedema, bronchospasm, pancytopenia/neutropenia, pseudomembranous colitis, TEN, hypotension, seizure
- Peds: rash (4.3%), elevated AST/ALT, neutropenia (11.3% in <2 yr at high dose)
- Lab: elevated transaminases/alkaline phosphatase, eosinophilia, positive Coombs
Pregnancy Crosses placenta; animal studies (2.2-2.9x MRHD) showed no embryo-/fetotoxicity or teratogenicity; no adequate human studies — use only if clearly needed
Lactation Excreted in human milk at <1% of maternal serum concentrations; consider temporary discontinuation of nursing and formula use
NO BOXED WARNINGS
Principal riskNo Gram-positive or anaerobic cover
Cost, est. cash$10–$500/bag or supply
Generic entry2010
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityUsually well tolerated at replacement doses; excessive dosing can cause agent-specific metabolic or organ toxicity.
Mechanism of action: Aztreonam ballicule
