Ceftriaxone sodium is an antibiotic that belongs to a group of drugs called cephalosporins. It is a white to yellowish-orange crystalline powder that is readily soluble in water, sparingly soluble in methanol and very slightly soluble in ethanol. The pH of a 1% aqueous solution is approximately 6.7. The color of solutions ranges from light yellow to amber, depending on the length of storage, concentration and dilutent used. The chemical formula of ceftriaxone sodium is C18H16N8Na2O7S3 3.5 H2O. It has a calculated molecular weight of 661.59.
Ceftriaxone sodium stops bacteria from making their cell wall, so the bacteria die. Ceftriaxone sodium is used to treat bacterial infections of the lower respiratory tract, urinary tract, skin, bone and joint, pelvis, and abdomen. Ceftriaxone sodium is a sterile, semi-synthetic, broad-spectrum, third generation cephalosporin antibiotic for intravenous or intramuscular administration. The bactericidal activity of Ceftriaxone results from inhibition of cell wall synthesis. Ceftriaxone has a high degree of stability in the presence of beta-lactamases, both penicillinases and cephalosporinases, of gram-negative and gram-positive bacteria. Ceftriaxone is widely distributed in body tissues and fluids. It crosses both inflamed and non-inflamed meninges, generally achieving therapeutic concentrations in the CSF. It crosses the placenta and low concentrations have been detected in breast milk. High concentrations are achieved in bile. About 40 to 65% of a dose of ceftriaxone is excreted unchanged in the urine, principally by glomerular filtration; the remainder is excreted in the bile and is ultimately found in the faeces as unchanged drug and microbiologically inactive compounds. Ceftriaxone has an N-methylthiotriazine side-chain and may have the potential to increase the effects of anticoagulants and to cause a disulfiram-like reaction with alcohol, as may cephalosporins with the related N-methylthiotetrazole side chain. Unlike many cephalosporins, probenecid does not affect the renal excretion of ceftriaxone.
Ceftriaxone sodium demonstrates nonlinear dose-dependent pharmacokinetics because of its protein binding; about 85 to 95% is bound to plasma protein depending on the plasma concentration of ceftriaxone. Mean peak plasma concentrations of about 40 and 80 micrograms per mL have been reported 2 hours after intramuscular injection of 0.5 and 1 g of ceftriaxone respectively. The plasma half-life of ceftriaxone is not dependent on the dose and varies between 6 and 9 hours; it may be prolonged in neonates. The half-life does not change appreciably in patients with moderate renal impairment, but it may be prolonged in severe renal impairment especially when there is also hepatic impairment.