Cefuroxime axetil clinical pharmacology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Abdurahman Khalil, M.D. [2]
Absorption and Metabolism
After oral administration, cefuroxime axetil is absorbed from the gastrointestinal tract and rapidly hydrolyzed by nonspecific esterases in the intestinal mucosa and blood to cefuroxime. Cefuroxime is subsequently distributed throughout the extracellular fluids. The axetil moiety is metabolized to acetaldehyde and acetic acid.
Pharmacokinetics
Approximately 50% of serum cefuroxime is bound to protein. Serum pharmacokinetic parameters for CEFTIN Tablets and CEFTIN for Oral Suspension are shown in Tables 1 and 2.
a Mean values of 12 healthy adult volunteers.
b Drug administered immediately after a meal.
a Mean age = 23 months.
b Drug administered with milk or milk products.
Comparative Pharmacokinetic Properties
A 250 mg/5 mL-dose of CEFTIN Suspension is bioequivalent to 2 times 125 mg/5 mL-dose of CEFTIN Suspension when administered with food (see Table 3). CEFTIN for Oral Suspension was not bioequivalent to CEFTIN Tablets when tested in healthy adults. The tablet and powder for oral suspension formulations are NOT substitutable on a milligram-per-milligram basis. The area under the curve for the suspension averaged 91% of that for the tablet, and the peak plasma concentration for the suspension averaged 71% of the peak plasma concentration of the tablets. Therefore, the safety and effectiveness of both the tablet and oral suspension formulations had to be established in separate clinical trials.
a Mean values of 18 healthy adult volunteers.
Food Effect on Pharmacokinetics
Absorption of the tablet is greater when taken after food (absolute bioavailability of CEFTIN Tablets increases from 37% to 52%). Despite this difference in absorption, the clinical and bacteriologic responses of patients were independent of food intake at the time of tablet administration in 2 studies where this was assessed.
All pharmacokinetic and clinical effectiveness and safety studies in pediatric patients using the suspension formulation were conducted in the fed state. No data are available on the absorption kinetics of the suspension formulation when administered to fasted pediatric patients.
Renal Excretion
Cefuroxime is excreted unchanged in the urine; in adults, approximately 50% of the administered dose is recovered in the urine within 12 hours. The pharmacokinetics of cefuroxime in the urine of pediatric patients have not been studied at this time. Until further data are available, the renal pharmacokinetic properties of cefuroxime axetil established in adults should not be extrapolated to pediatric patients.
Because cefuroxime is renally excreted, the serum half-life is prolonged in patients with reduced renal function. In a study of 20 elderly patients (mean age = 83.9 years) having a mean creatinine clearance of 34.9 mL/min, the mean serum elimination half-life was 3.5 hours. Despite the lower elimination of cefuroxime in geriatric patients, dosage adjustment based on age is not necessary (see PRECAUTIONS: Geriatric Use).
References
http://www.accessdata.fda.gov/drugsatfda_docs/label/2007/050605s042lbl.pdf