[The pharmacokinetics of ciprofloxacin in patients with renal function of various degrees]

The pharmacokinetics of ciprofloxacin was investigated in 12 patients with renal function of various degrees. A single dose of 500 mg of ciprofloxacin was administered after overnight fasting. Serum and urine samples were collected serially at different intervals and subjected to bioassay and HPLC. Pharmacokinetic parameters were analyzed by assuming an open two-compartment model. Apparent difference was observed in pharmacokinetic parameters between patients with severe impairment of renal function and those with normal renal function. For the former group, the area under the curve of serum concentration versus time was tripled (42.22 +/- 12.48 vs. 14.55 +/- 6.66 mg.h-1.ml-1, the renal clearance of ciprofloxacin was reduced to one-tenth (22.43 +/- 12.08 vs. 193.13 +/- 65.14 ml/min), and the elimination half-life was prolonged twofold (9.28 +/- 2.42 vs. 4.72 +/- 1.35 h). The correlation between renal drug clearance and Ccr was highly significant (r = 0.935, P < 0.001). On the basis of these findings, it is suggested that a reduction of one half of the dose of ciprofloxacin or an increase of a double of the administration time interval may be indicated in chronic renal failure with GFR less than 25 ml/min.