What is the dosage and treatment guidelines for Aztreonam (Aztreonam) injection?

Aztreonam Injection Dosage and Treatment Guidelines

Aztreonam should be dosed based on infection type, with 500 mg to 2 g IV every 6-12 hours, and treatment continued for at least 48 hours after the patient becomes asymptomatic or evidence of bacterial eradication has been obtained. 1

Standard Dosing for Adults

• Urinary tract infections: 500 mg or 1 g IV every 8 or 12 hours 1
• Moderately severe systemic infections: 1 g or 2 g IV every 8 or 12 hours 1
• Severe systemic or life-threatening infections: 2 g IV every 6 or 8 hours 1
• For Pseudomonas aeruginosa infections, 2 g every 6 or 8 hours is recommended at initiation of therapy due to the serious nature of these infections 1

Pediatric Dosing

• Mild to moderate infections: 30 mg/kg IV every 8 hours 1
• Moderate to severe infections: 30 mg/kg IV every 6 or 8 hours 1
• Maximum recommended dose is 120 mg/kg/day 1

Dosing in Renal Impairment

• For patients with creatinine clearance between 10-30 mL/min/1.73 m², halve the dose after an initial loading dose of 1 g or 2 g 1
• For severe renal failure (creatinine clearance <10 mL/min/1.73 m²), give the usual initial dose followed by one-fourth of the usual dose at the fixed interval 1
• For hemodialysis patients, give one-eighth of the initial dose after each hemodialysis session in addition to maintenance doses 1

Duration of Therapy

• Most bacterial infections: 7-14 days 2
• Complicated urinary tract infections: 5-7 days 2, 3
• Hospital-acquired or ventilator-associated pneumonia: 10-14 days 2, 3
• Bloodstream infections: 7-14 days 2
• Treatment should continue for at least 48 hours after the patient becomes asymptomatic 1

Special Considerations

Metallo-β-Lactamase-Producing Carbapenem-Resistant Organisms

• Aztreonam is uniquely active against metallo-β-lactamase (MBL)-producing carbapenem-resistant Enterobacteriaceae (CRE) 4
• For MBL-producing CRE infections, combination of ceftazidime-avibactam with aztreonam is recommended due to significantly lower mortality rates (19.2% vs 44%) compared to other treatment options 5
• Standard aztreonam dosing in this combination is 2 g IV every 8 hours 5

Administration

• Intravenous route is recommended for patients requiring single doses greater than 1 g or those with bacterial septicemia, localized parenchymal abscess, peritonitis, or other severe systemic or life-threatening infections 1
• For IV bolus injection: Constitute with 6-10 mL Sterile Water for Injection and inject slowly over 3-5 minutes 1
• For IV infusion: Initially constitute with at least 3 mL Sterile Water for Injection per gram of aztreonam, then further dilute with compatible IV solutions 1
• Any aztreonam infusion should be completed within a 20-60 minute period 1

Important Caveats

• As monotherapy, aztreonam does not cover gram-positive bacteria or anaerobes, so combination therapy is recommended for mixed infections 6, 7
• In hospital-acquired pneumonia where MRSA coverage is not used but aztreonam is chosen due to penicillin allergy, additional coverage for methicillin-sensitive Staphylococcus aureus (MSSA) should be included 4
• Clinical improvement should be evident within 48-72 hours of initiating appropriate therapy 2
• Aztreonam is incompatible with nafcillin sodium, cephradine, and metronidazole 1
• Premature discontinuation of therapy before clinical stability is achieved should be avoided 2