Pharmacokinetics of ciprofloxacin in the elderly

The pharmacokinetics of ciprofloxacin, administered orally as a 250-mg tablet were compared in 10 young (age 20-30 years) and 10 elderly (age 60-73 years) healthy volunteers. The time to peak serum concentrations was about 80 min in both age groups, although the maximum concentration attained was significantly greater in the old (1.7 mg/l) than the young (1.2 mg/l). Area under the plasma concentration-time curve, corrected for body weight, was on average 48% greater in the elderly, but the mean terminal elimination half-life was not significantly different, averaging 4.3 h in the old and 3.7 h in the young. Overall 24-hour urinary recovery in both age groups was comparable. The differences may be explained by a reduced volume of distribution of ciprofloxacin in old age and do not suggest a general need for significant dose alteration in the elderly.