Zinacef Mechanism of Action

Pharmacology: Pharmacodynamics: Tablet: The prevalence of acquired resistance is geographically and time dependent and for select species may be very high. Local information on resistance is desirable, particularly when treating severe infections. (See Table 1.)

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Injection: Cefuroxime is a well characterised and effective antibacterial agent which has bactericidal activity against a wide range of common pathogens, including β-lactamase producing strains. Cefuroxime has good stability to bacterial β-lactamase, and consequently is active against many ampicillin-resistant or amoxicillin-resistant strains.
The bactericidal action of cefuroxime results from inhibition of cell wall synthesis by binding to essential target proteins.
The prevalence of acquired resistance is geographically and time dependent and for select species may be very high. Local information on resistance is desirable, particularly when treating severe infections. (See Table 2.)

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Pharmacokinetics: Tablet: Absorption: After oral administration Cefuroxime axetil (Zinacef) is slowly absorbed from the gastrointestinal tract and rapidly hydrolysed in the intestinal mucosa and blood to release cefuroxime into the circulation.
Optimum absorption occurs when it is administered shortly after a meal.
Following administration of Cefuroxime axetil (Zinacef) tablets peak serum levels (2.1 mg/L for a 125 mg dose, 4.1 mg/L for a 250 mg dose, 7.0 mg/L for a 500 mg dose and 13.6 mg/L for a 1 g dose) occur approximately 2 to 3 hours after dosing when taken after food.
Distribution: Protein binding has been variously stated as 33 to 50% depending on the methodology used.
Metabolism: Cefuroxime is not metabolized.
Elimination: The serum half-life is between 1 and 1.5 hours.
Cefuroxime is excreted by glomerular filtration and tubular secretion.
Concurrent administration of probenecid increases the area under the mean serum concentrations time curve by 50%.
Renal impairment: Cefuroxime pharmacokinetics have been investigated in patients with various degrees of renal impairment. Cefuroxime elimination half-life increases with decrease in renal function which serves as the basis for dosage adjustment recommendations in this group of patients (see Dosage & Administration). In patients undergoing haemodialysis, at least 60% of the total amount of cefuroxime present in the body at the start of dialysis will be removed during a 4-hour dialysis period. Therefore, an additional single dose of cefuroxime should be administered following the completion of haemodialysis.
Injection: Peak levels of cefuroxime are achieved within 30 to 45 minutes after i.m. administration.
Protein binding has been variously stated as 33-50% depending on the methodology used.
Concentrations of cefuroxime in excess of the minimum inhibitory levels for common pathogens can be achieved in bone, synovial fluid and aqueous humour. Cefuroxime passes the blood-brain barrier when the meninges are inflamed.
Cefuroxime is not metabolised and is excreted by glomerular filtration and tubular secretion.
The serum half-life after either i.m. or i.v. injection is approximately 70 minutes.
In the first weeks of life the serum half-life of cefuroxime can be 3 to 5 times that in the adult.
Concurrent administration of probenecid prolongs the excretion of the antibiotic and produces an elevated peak serum level. There is an almost complete recovery (85 to 90%) of unchanged cefuroxime in urine within 24 hours of administration. The major part is excreted in the first 6 hours.
Serum levels of cefuroxime are reduced by dialysis.
Toxicology: Pre-clinical Safety Data: Tablet: Animal toxicity studies indicated that cefuroxime axetil is of low toxicity with no significant findings.
Injection: No additional data of relevance.