Ciprofloxacin distribution in prostatic tissue and fluid following oral administration.

The penetration of ciprofloxacin into prostatic tissue was studied following oral administration of 500 mg either once or repeatedly in 12-hourly intervals. Following single administration ciprofloxacin was rapidly absorbed from the gastrointestinal tract peaking 1-2 h after administration. Elimination from serum was slow, the half life being 4.3 h. No significant rise in serum concentrations was noticed following repeated administration. Ciprofloxacin was concentrated in the prostatic tissue, levels being on average twice as high as the corresponding serum concentrations. The ratios between prostate and serum levels following single and repeated administration were 227 and 214%, respectively. Intraindividual analysis of prostate concentrations in different areas of the prostatic gland revealed a homogeneous distribution within the prostate. Penetration of ciprofloxacin into prostatic fluid was studied in 11 patients 2-4.5 h after administration. At these points ratios between prostatic fluid and serum ranged between 1.5 and 450%.