Ceftrex Mechanism of Action

The bactericidal activity of ceftriaxone results from inhibition of bacterial cell wall synthesis. Ceftriaxone exerts in-vitro activity against a wide range of gram-negative and gram-positive microorganisms. Ceftriaxone is highly stable to most β-lactamases, both penicillinases and cephalosporinases, of gram-positive and gram-negative bacteria. Ceftriaxone is usually active against the following microorganisms in-vitro and in clinical infections.
Aerobes gram-positive: Staphylococci, Streptococci, beta-hemolytic, Streptococcus pneumoniae, Streptococcus pyogenes.
Aerobes gram-negative: Acinetobacter sp., Citrobacter sp., Enterobacter sp., Escherichia coli, Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella sp., Morganella (Proteus) morganii, Neisseria gonorrhoeae, Neisseria meningitidis, Proteus mirabilis, Proteus vulgaris, Providencia sp., Providencia rettgeri, Pseudomonas aeruginosa, Salmonella sp., Salmonella typhi, Serratia sp., Shigella sp.
Anaerobes: Bacteroides sp., Bacteroides fragilis, Clostridium sp., Eubacterium sp., Fusobacterium sp., Peptococcus sp., Peptostreptococcus sp.
PHARMACOKINETICS: Ceftriaxone exhibits nonlinear dose-dependent pharmacokinetics. All basic pharmacokinetics parameters (except elimination half-life) are dose dependent if based on total drug concentrations. Following IM administration of a single ceftriaxone dose of 0.5 - 1 g in healthy adults, the drug appears to be completely absorbed, and peak serum concentrations are attained 1.5 - 4 hours after the dose.
The volume of distribution of ceftriaxone is dose-dependent and ranges from 5.8 - 13.5 L in healthy adults. The volume of distribution of ceftriaxone is 0.497 - 0.608 L/kg in neonates 1 - 45 days of age and 0.26 - 0.54 L/kg in children 1.5 months to 16 years of age following a single ceftriaxone dose of 50 - 100 mg/kg.
Following IM administration, ceftriaxone is widely distributed into body tissues and fluids including the gallbladder, lungs, bone, heart, bile, prostate adenoma tissue, uterine tissue, atrial appendage, sputum, tears, middle ear fluid and synovial fluids. Ceftriaxone generally diffuses into CSF following IM administration of the drug. The degree of protein binding of ceftriaxone is concentration dependent and decreases nonlinearly with increasing concentrations of the drug. Ceftriaxone binds mainly to albumin. Protein binding of ceftriaxone is lower in neonates and children than in adults because of decreased plasma albumin concentrations in this age group.
In adults with normal renal and hepatic function, the distribution half-life of ceftriaxone is 0.12 - 0.7 hours and the elimination half-life is 5.4 - 10.9 hours. Ceftriaxone is excreted both by renal and nonrenal mechanisms. The drug is excreted principally in urine by glomerular filtration and also is excreted in feces via bile. Following IM administration of a single dose of ceftriaxone in adults with normal renal and hepatic function, 33 - 67% of the dose is excreted in urine as unchanged drug and the remainder of the dose is excreted in feces as unchanged drug.
Serum clearance of ceftriaxone is dose-dependent and ranges from 9.7 - 25 mL/minute in healthy adults. The serum half - life of ceftriaxone is longer in neonates than in older children and adults. The elimination half-life of ceftriaxone is only slightly prolonged in patients with moderately impaired renal function. Studies in patients with hepatic impairment indicate that the pharmacokinetics of ceftriaxone are not generally altered in these patients. Ceftriaxone is not removed by hemodialysis or peritoneal dialysis.