Age and gender effects on the pharmacokinetics of gatifloxacin.

STUDY
OBJECTIVE: To compare the pharmacokinetics and safety of gatifloxacin in elderly (> or = 65 yrs) and young (18-45 yrs) men and women.
DESIGN: Open-label, parallel-group, single-dose study.
SETTING: GFI Pharmaceutical Services Inc., Evansville, Indiana, USA.
SUBJECTS: Forty-eight healthy subjects in four groups of 12 each.
INTERVENTIONS: Subjects received single oral doses of gatifloxacin 400 mg. Serial blood and urine samples were collected for 96 hours after dosing to determine drug concentrations.
MEASUREMENTS AND MAIN RESULTS: Age and gender had moderate effects on the pharmacokinetics of gatifloxacin. Elderly women had a 21% higher geometric mean peak plasma concentration (Cmax) and a 32% higher area under the plasma concentration-time curve (AUC0-infinity) than young women. Adjustment for creatinine clearance had only a slight effect on Cmax but reduced the estimated effect of age on AUC0-infinity in women from a 32% increase to a 15% increase. Gender effects on pharmacokinetic values were noted among elderly subjects only. Geometric means for Cmax and AUC0-infinity were 21% and 33% higher, respectively, for elderly women and elderly men. Adjustment for body weight reduced these differences to 11% and 20%, respectively.
CONCLUSION: The effects of age on gatifloxacin pharmacokinetic values were largely attributed to declining renal function, whereas those of gender were largely attributed to differences in body weight. These modest age- and gender-related differences do not warrant dosage adjustment.

RCT Entities:   Population Interventions Outcomes