Pharmacokinetics of cefoperazone in ambulatory elderly volunteers compared with young adults

Two groups of 10 healthy ambulatory subjects, i.e., a group of 10 persons less than or equal to 30 years of age (mean age, 27.6 years) and a group of 10 persons greater than or equal to 65 years of age (mean age, 70 years), were randomized in a single-trial crossover design to receive 1 and 2 g of cefoperazone with a 1-week washout between doses. The elderly subjects had both decreased estimated creatinine clearances and decreased albumin concentrations in serum. Cefoperazone concentrations in serum of elderly persons were significantly higher at each interval from 30 min to 6 h for the 2-g dose. Compared with that in younger persons, the total clearance in elderly subjects was significantly lower for both the 1- and 2-g doses, the renal clearance was significantly lower for the 2-g dose, and the area under the curve was significantly higher for the 2-g dose in the elderly persons. The half-life at beta phase was higher in the elderly persons at both the 1- and 2-g doses but not significantly so. Changes in total clearance and area under the curve and higher levels in serum in the elderly persons suggest a longer duration of antimicrobial activity in this age group.