Pharmacology: Pharmacodynamics: Mechanism of Action: Sterile Ceftriaxone Sodium is bactericidal. Like other beta lactams, Sterile Ceftriaxone Sodium kills bacteria by preventing their cell wall synthesis.
Pharmacokinetics: Sterile Ceftriaxone Sodium is completely absorbed following intramuscular administration with peak plasma concentration occurring 2-3 hours after the dose. When Sterile Ceftriaxone Sodium is given by IV infusion, plasma levels were substantially higher after single IM doses of 0.5 and 1.0 g mean plasma were, at 30 minutes 30 and 40 mcg/mL, at 2 hours 43 and 76 mcg/mL, at 4 hours, 39 and 68 mcg/mL and at 12 hours 16 and 29 mcg/mL. The plasma half-life of Sterile Ceftriaxone Sodium is not dependent on the dose and carries between 6 and 9 hours. 85 to 95% of Sterile Ceftriaxone sodium is reversibly bound to plasma proteins. Sterile Ceftriaxone Sodium is penetrates well into most tissues and body fluids including CSF (with inflamed and non-inflamed meninges). High concentrations are rich in bile.
Sterile Ceftriaxone Sodium is metabolized in the body. 33 to 67% of the dose is excreted unchanged in the urine. The rest is excreted is unchanged in the bile and is ultimately excreted in the feces as inactive compounds.
Elimination half-life is only minimally altered in the elderly or in patients with renal or hepatic dysfunction. However, it is decreased in neonates.
Microbiology: Antimicrobial Activity: Sterile Ceftriaxone Sodium is highly stable against beta lactamases including both penicillinases and cephalosporinase produced by Gram negative and Gram positive organisms. Sterile Ceftriaxone Sodium is active against most Gram positive and Gram negative aerobes and some anaerobes.
Gram positive bacteria: Sterile Ceftriaxone Sodium is very active against S. Pneumoniae and Streptococci groups A and B. Other gram positive organisms susceptible to Sterile Ceftriaxone Sodium include Staphylococcus aureus including penicillinase producing strains and Staph. Epidermidis.
Gram negative bacteria: Sensitive Organisms include E. coli, Citrobacter freundii, C. diversus, Klebsiella spp., K. pneumoniae, Enterobacter spp., E. aerogenes, E. cloacae, Serratia spp., and Shigella spp., Morganella morganii and P. vulgaris, Neisseria are sensitive to Sterile Ceftriaxone Sodium. These include both penicillinase producing and non producing gonococci and N. meningitidis. Haemophilus influenzae including ampicillin resistant strains are sensitive.
Anaerobic organisms: Sterile Ceftriaxone Sodium is active against Bacteroides fragilis, B. melaninogenicus, B. Bivius, Clostridium spp., and Peptostreptococcus. Sterile Ceftriaxone Sodium is active against Treponema to a similar extent as benzyl penicillin and highly active against Borrelia burgdorferi.