Mechanism of Action and Antimicrobial Spectrum
Like all beta-lactam antibiotics, cefuroxime inhibits bacterial cell wall synthesis, exerting a bactericidal effect. A key evolutionary feature of second-generation agents is their greater stability against $eta$-lactamases compared to first-generation drugs.
Features of the activity spectrum:
- Gram-negative flora: Activity is significantly higher than that of the first generation. The spectrum is expanded to include Haemophilus influenzae (cefuroxime is a group leader against this pathogen), Neisseria spp., certain strains of Enterobacter aerogenes, and enteric bacteria (E. coli, Proteus, Salmonella, Shigella).
- Gram-positive flora: Efficacy is somewhat lower compared to first-generation cephalosporins.
- Spectrum limitations: The drug is inactive against Pseudomonas aeruginosa. Additionally, unlike other second-generation agents (such as cefotetan and cefoxitin), cefuroxime lacks anti-anaerobic activity (it does not cover Bacteroides species).
Pharmacokinetics
The pharmacokinetic profile depends on the route of administration. Cefuroxime penetrates well into tissues and organs and is eliminated predominantly via the kidneys.
Parenteral formulation (Cefuroxime):
- Administered intramuscularly (IM) or intravenously (IV).
- The half-life requires dosing every 8 hours (3–4 times daily).
- Blood-Brain Barrier (BBB) penetration: Crosses the blood-brain barrier only in the presence of meningeal inflammation.
Oral formulation (Cefuroxime axetil):
- Functions as a prodrug—an ester derivative of cefuroxime adapted for gastrointestinal absorption.
- Features a more convenient dosing schedule: administered twice daily.
Clinical Indications
Due to its activity against Haemophilus influenzae and Streptococcus pneumoniae, cefuroxime is frequently used to treat community-acquired pneumonia and other upper and lower respiratory tract bacterial infections.
Other indications include:
- Urinary tract infections (UTIs).
- Skin and soft tissue infections.
- Bone and joint infections.
- Perioperative antibiotic prophylaxis in surgery (a class effect).
Adverse Effects
The drug exhibits a safety profile typical of cephalosporins.
- Common reactions: Diarrhea, transient elevations in hepatic transaminases, and allergic reactions (hypersensitivity, with potential cross-allergenicity with penicillins).
- Rare but severe reactions: Agranulocytosis, interstitial nephritis.
Formulations and Dosing
The drug is available for both enteral and parenteral use.
1. Oral administration (tablets):
- Dosages: 0.125 g, 0.25 g, and 0.5 g.
- Regimen: 0.125–0.5 g twice daily.
2. Injectable administration (powder in vials):
- Dosages: 0.75 g and 1.5 g.
- Regimen: Intramuscularly or intravenously 0.75–1.5 g 3–4 times daily (every 8 hours).