Pharmacokinetic study of cefuroxime in the elderly.

1 The pharmacokinetics of cefuroxime have been investigated in 18 patients at least 70 years old. The drug was given either by continuous infusion (7 cases) or by multiple injections (11 cases) for 3 to 11 days (mean duration: 7 days). 2 The unchanged drug was assayed in blood plasma and in the urine by high performance liquid chromatography (h.p.l.c). 3 Cefuroxime was cleared, unchanged, almost exclusively by the kidneys, even when kidney function was impaired. Creatinine clearance ranged from 1.02 to 4.08 1/h (17 to 68 ml/min) in this group of patients and plasma clearance of cefuroxime varied from 1.02 to 8.16 1/h (17 to 136 ml/min) (r = 0.7 P less than 0.001 for linear correlation), but the apparent rate constant for nonrenal elimination remained quite small (average: 0.04 h-1) and independent of creatinine clearance (r = 0.06, n = 17). 4 Since creatinine clearance decreases sharply with age, it might be suggested that cefuroxime dosage be related to creatinine clearance in the elderly, even when no renal impairment is suspected.