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Pharmacology: Roxicef S125/Roxicef S250: Antimicrobial Action: Cefuroxime is bactericidal and has a similar spectrum of antimicrobial action and pattern of resistance to those of cefamandole. It is more resistant to hydrolysis by beta-lactamases than cefamandole and therefore may be more active against beta-lactamase producing strains, Haemophilus influenza and Neisseria gonorrhea. However, treatment failures have occurred in patients with H. influenza meningitis given cefuroxime and might be associated with a relatively high minimum bactericidal concentration when compared with the minimum inhibitory concentration or with a significant inoculum effect. Reduced affinity of penicillin-binding proteins for cefuroxime has also been reported to be responsible for resistance in a beta-lactamase-negative strain of H. influenza.
Pharmacokinetics: Cefuroxime axetil is absorbed from the gastrointestinal tract and is rapidly hydrolyzed in the intestinal mucosa and blood to cefuroxime; absorption is enhanced in the presence of food. Peak plasma concentrations are reported about 2 to 3 hours after an oral dose. The sodium salt is given by intramuscular or intravenous injection. Peak plasma concentrations of about 27 mcg per mL have been achieved 45minutes after an intramuscular dose of 750 mg with measurable amounts present 8 hours after a dose. Up to 50% of cefuroxime in the circulation is bound to plasma proteins. The plasma half-life is about 70 minutes and is prolonged in patients with renal impairment and in neonates. Cefuroxime is widely distributed in the body including pleural fluid, sputum, bone, synovial fluid and aqueous humor, but only achieves therapeutic concentrations in the CSF when the meninges are inflamed. It crosses the placenta and has been detected in breastmilk.
Cefuroxime is excreted unchanged by glomerular filtration and renal tubular secretion, and high concentrations are achieved in the urine. On injection, most of the dose of a dose of cefuroxime is excreted within 24 hours, the majority within 6 hours probenecid competes for renal tubular secretion with cefuroxime resulting higher and more prolonged plasma concentrations of cefuroxime. Small amounts of cefuroxime are excreted in bile.
