Aztreonam
Common Brand Names: Azactam
Therapeutic Class: A monobactam antibiotic
Common Injectable Dosage Forms:
Powder for Injection (Lyophilized cake): 500 mg, 1 g, 2 g as either vials for injection or 100 mL infusion bottles
Frozen Premixed Solution: 1 g, 2 g
Dosage Ranges:
For the treatment of lower respiratory tract infections (including pneumonia and bronchitis), septicemia, skin and skin structure infections (including those associated with postoperative wounds or ulcers or burns), intra-abdominal infections (including peritonitis), and gynecologic infections (including endometritis and pelvic cellulitis) caused by susceptible gram-negative bacteria: 1-2 g every 8-12 hours.
For the treatment of complicated and uncomplicated urinary tract infections (including pyelonephritis and cystitis): 500 mg or 1 g every 8-12 hours.
For the treatment of moderately severe systemic infections: Adults should receive 1-2 g every 8-12 hours. Severe systemic or life-threatening infections, especially those involving P. aeruginosa, may require 2 g every 6-8 hours. The maximum adult dosage recommended is 8 g/day.
Pediatric dosage (1 month to 15 years) has been established at 30-59 mg/kg every 4-8 hours.
Administration and Stability: For direct IV injection, the dose should be diluted with 6-10 mL of diluent and injected over a period of 3-5 minutes. For intermittent IV fusion, aztreonam should be diluted with a compatible solution to a final concentration not exceeding 20 mg/mL and infused over a period of 20-60 minutes. For IM injection at least 3 mL of an appropriate diluent should be added per gram of aztreonam and injected deeply into a large muscle. pH: 4.5-7.5
Pharmacology/Pharmacokinetics: Aztreonam is a synthetic monobactam antibiotic that exhibits its bactericidal effect by inhibiting bacterial cell wall synthesis. Aztreonam is active against many gram-negative bacteria, including most Enterobacteriaceae and P. aeruginosa, but has little or no activity against gram-positive or anaerobic bacteria. Aztreonam is 100% bioavailable when given IM, producing peak serum levels in 1 hours. The drug is excreted primarily unchanged in the urine and has an elimination half-life of 1.7 hours, which is prolonged in renal failure, requiring dosage adjustments.
Drug and Lab Interactions: Aztreonam, like most cephalosporins, can produce false-positive Benedict’s test for urine glucose. The antibacterial activity is additive or synergistic with aztreonam is combined with other antibiotics such as aminoglycosides, beta-lactams, and clindamycin, and should always be used in combination in the treatment of mixed infections, or those of unknown etiology, to ensure coverage gram-positive and anaerobic bacteria.
Contraindications/Precautions: Care should be taken to determine if patients have any previous history of hypersensitivity to any beta-lactams, as some degree of cross-sensitivity has been demonstrated. Aztreonam appears to lack the nephrotoxic effects seen with aminoglycosides, but elevations in hepatic function tests have been frequent. As with other antibiotics, superinfections are a concern during aztreonam therapy. Pregnancy Category B.
Monitoring Parameters: LFTs, BUN, Cr
Adverse Effects: Nausea, vomiting, diarrhea, and other GI effects have been reported with aztreonam therapy. Skin rash, phlebitis, and blood dyscrasias have also been reported as other adverse effects associated with the use of aztreonam.
Common Clinical Applications: An effective antibiotic against gram-negative bacteria. Usually used in combination with another antibiotic in order to cover gram-positive infections.
