Pharmacokinetics of cefodizime in the elderly following single and repeated intravenous administration of 1 g

In an open, crossover study of 12 patients of mean age 74 (range 64-88) who required perioperative prophylactic antibiotic therapy, cefodizime was administered as a single iv infusion of 1 g, and repeated infusions of 1 g twice daily for 4.5 days. Serum and urine concentrations of cefodizime were determined by high performance liquid chromatography. The following pharmacokinetic indices were estimated after single and repeated (values in brackets) dosing: C0.15h 269 (285) mg/l; C12h 8.7 (8.5) mg/l; AUC 557 (494) mg.h/l; Clt 1.93 (2.20) l/h; Vdss 8.62 (8.56) l; T1-2 4.06 (4.07) h; U0-36h: 569 (624) mg; and Clr0-12h 1.17 (1.39) l/h. No statistically significant differences in these values were found between single and repeated dose treatments. These results demonstrate a lack of accumulation and no changes in the pharmacokinetic profile of cefodizime during repeated dosing in the elderly. No modification of the dosage regimen of cefodizime would appear to be necessary in the elderly as compared with young healthy subjects.