Accumulation of new quinolones in the blood of elderly patients.

The correlation between serum levels of five new quinolones (norfloxacin, ofloxacin, enoxacin, ciprofloxacin and lomefloxacin), age and 24 h creatinine clearance was studied in 180 patients. One of five new quinolones was orally administered, before transurethral resection of the prostate, at the dosage of 200 mg three times daily for 3 consecutive days. Serum levels were checked 5.5 h or about 17 h after the final administration. Creatinine clearance was found to be negatively correlated with aging (P < 0.001). After oral administration, the level of certain accumulated new quinolones in serum increased with the age of patients (P < 0.001-0.1). This tendency was more marked for ofloxacin, lomefloxacin and enoxacin than for ciprofloxacin and norfloxacin. The investigators concluded that the level of accumulated new quinolones in serum with aging is correlated to the 24 h urinary excretion rate of each new quinolone. These results indicate that ofloxacin, lomefloxacin and enoxacin, which have higher 24 h urinary excretion rates, should be administered at lower doses according to the age of the patient, in order to prevent adverse reactions.