Mechanism of action
Aztreonam contains a monocyclic beta-lactam ring. Its uniqueness lies in its high resistance to beta-lactamases produced by Gram-negative bacteria. The drug disrupts bacterial cell wall synthesis, leading to cell death. Notably, it is degraded by beta-lactamases from Gram-positive bacteria and anaerobes, which determines its narrow spectrum of activity.
Pharmacological effects
The drug exhibits pronounced activity against Escherichia coli, Pseudomonas aeruginosa, Proteus spp., Klebsiella spp., Haemophilus influenzae, as well as gonococci and meningococci. Aztreonam has no effect on Gram-positive flora and anaerobic microorganisms (including Bacteroides).
Indications for use
Aztreonam is a reserve drug. Its key advantage is low cross-allergenicity, allowing its use in patients with severe penicillin allergies. Main indications: lower respiratory tract infections (including nosocomial pneumonia), intra-abdominal infections, pelvic infections, severe urinary tract infections, skin, soft tissue, bone and joint infections, as well as systemic infections (sepsis, meningitis).
Side effects
Possible adverse effects during therapy include: gastrointestinal dyspepsia, allergic skin reactions, headache. Local reactions such as injection-site phlebitis are frequently observed with parenteral administration.
Prescription details
The drug is administered parenterally (IV or IM) as a bolus or infusion. The single dose is 0.5–2.0 g given at 8–12 hour intervals. The maximum daily dose (MDD) is 8.0 g. Aztreonam is indispensable when other antibiotics fail in Gram-negative infections.
Briefly: answers to topical questions
Which antibiotics are combined with aztreonam for empirical therapy of mixed infections?
Aztreonam is combined with metronidazole. This combination is used for severe Grade III acute cholecystitis as well as healthcare-associated infections.
What are the contraindications for prescribing aztreonam?
Contraindications for prescribing aztreonam include early infancy and the presence of allergic reactions.
- Infancy — the drug is contraindicated in children under 9 months of age.
- Hypersensitivity — a general contraindication for prescribing antibiotics.
At the same time, pregnancy is not an absolute contraindication, as the drug belongs to Category B (no evidence of risk in animal studies, human studies not adequate).
Aztreonam is the "Az" (first) among monobactams, works only on "minus" (Gram-negative), and is safe for "penicillin-allergic patients".
Class and exam questions
Why is aztreonam inactive against Gram-positive bacteria?
Its molecule is degraded by beta-lactamases produced by Gram-positive microorganisms.
What is the main clinical advantage of aztreonam?
Low cross-allergenicity with penicillins, making it the drug of choice in penicillin allergy.
Can aztreonam be used for anaerobic infections?
No, the drug has no activity against anaerobes, including Bacteroides.
What else to study on this topic
- Comparative characteristics of monobactams and carbapenems.
- Mechanisms of resistance development to beta-lactams.
- Management tactics for patients with penicillin allergies when choosing antibiotic therapy.
- Pharmacokinetic parameters of aztreonam (protein binding, excretion).
- Specifics of therapy for nosocomial infections caused by P. aeruginosa.
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