Aztreonam IV Dilution and Administration
Aztreonam should be diluted in Sterile Water for Injection, 0.9% Sodium Chloride, or other compatible IV solutions at concentrations not exceeding 2% w/v (20 mg/mL), and administered either as a bolus over 3-5 minutes or as an infusion over 20-60 minutes. 1
Recommended Dilution Fluids
Aztreonam is compatible with multiple IV solutions for dilution 1:
Primary Options:
- Sterile Water for Injection, USP 1
- 0.9% Sodium Chloride Injection, USP 1
- 5% or 10% Dextrose Injection, USP 1
- Lactated Ringer's Injection, USP 1
Additional Compatible Solutions:
- Dextrose and Sodium Chloride combinations (5%:0.9%, 5%:0.45%, 5%:0.2%) 1
- Sodium Lactate Injection (M/6 Sodium Lactate) 1
- Various balanced salt solutions (Normosol-R, Isolyte E, Plasma-Lyte M) 1
- 5% or 10% Mannitol Injection 1
Dilution Ratios and Preparation
For IV Bolus Injection:
- Reconstitute vial with 6-10 mL Sterile Water for Injection 1
- This creates a concentrated solution for direct slow injection 1
For IV Infusion:
- Initial reconstitution: Add at least 3 mL Sterile Water for Injection per gram of aztreonam 1
- Further dilution: Transfer to compatible IV solution to achieve final concentration not exceeding 2% w/v (20 mg/mL) 1
- For a standard 2g dose, this means a minimum final volume of 100 mL 1
Administration Methods
Bolus Administration:
- Inject slowly over 3-5 minutes directly into vein or IV tubing 1
- Flush tubing before and after if administering with incompatible drugs 1
Infusion Administration:
- Complete infusion within 20-60 minutes 1
- Standard adult dosing is 2g IV every 8 hours for serious gram-negative infections including hospital-acquired pneumonia 2
Stability Considerations
Storage at Room Temperature (15-30°C):
- Solutions ≤2% w/v: Use within 48 hours 1
- Solutions >2% w/v in Sterile Water or 0.9% NaCl: Use within 48 hours 1
- Solutions >2% w/v in other diluents: Use promptly 1
Refrigerated Storage (2-8°C):
- Solutions ≤2% w/v: Use within 7 days 1
- Solutions >2% w/v in Sterile Water or 0.9% NaCl: Use within 7 days 1
Critical Incompatibilities
Aztreonam is incompatible with the following and must not be mixed 1:
When using Y-site administration with other drugs, flush the common delivery tube before and after aztreonam delivery 1. The stability of aztreonam decreases when mixed with ampicillin, though ampicillin stability paradoxically increases 3.
Pharmacokinetic Rationale
The recommended dilution and administration approach is based on aztreonam's pharmacokinetic profile 4, 5:
- Peak serum levels occur within 5 minutes after IV bolus 4
- Elimination half-life is 1.7 hours 4, 5
- After a 2g IV dose, therapeutic concentrations exceed MIC90 for most Enterobacteriaceae for 8 hours and for Pseudomonas aeruginosa for 6 hours 4
- Volume of distribution is approximately 0.16-0.18 L/kg 4, 5
Common Pitfalls to Avoid
- Do not use glucose-containing solutions if preparing high-concentration (>2% w/v) solutions for extended storage, as stability data are limited 1
- Do not mix with incompatible antibiotics in the same container or Y-site without adequate flushing 1
- Do not exceed 2% w/v concentration for routine infusions to ensure stability 1
- Adjust dosing in renal impairment, as 60-70% is excreted unchanged in urine 4