Pharmacokinetics of oral ciprofloxacin, 100 mg single dose, in volunteers and elderly patients.

The pharmacokinetics of ciprofloxacin following a single 100 mg oral dose were evaluated in elderly patients (mean age 74 years), laboratory staff (30-40 years) and students (less than 20 years). There were no significant differences in serum Tmax (1.2-1.3 h) or in overall serum elimination half-life (3.7-4.0 h) but Cmax in elderly patients was more than double that in young volunteers (P less than 0.005). The serum AUC value was greater both in fasting students (1.4 mg/h/l) compared with the same subjects after food (1.09: P less than 0.01) and, after food, in elderly patients (1.95) compared with students (0.81: P less than 0.005). Urinary recoveries were greater in fasting subjects and in all categories of volunteers compared with elderly patients. However, in the elderly, urinary ciprofloxacin concentrations (0-6 h mean 66 mg/l: range 17.4-200 mg/l) were more than adequate for the eradication of urinary pathogens.