PENETRATION OF CIPROFLOXACIN INTO PROSTATIC FLUID, EJACULATE AND SEMINAL FLUID IN VOLUNTEERS AFTER AN ORAL DOSE OF 750 MG

To evaluate an effective dose for the treatment of bacterial prostatit is the concentrations of ciprofloxacin were measured in prostatic flui d, ejaculate and the cell-free seminal fluid of 15 healthy volunteers who received an oral dose of 750 mg. ciprofloxacin while in a fasting state. Venous blood samples were taken in all subjects at 1, 2, 3 and 4 hours. In 6 subjects blood samples were also taken after 8 and 12 ho urs. Urine was collected in all subjects during 0 to 4 hours and in th e 6 subjects also during 4 to 8 hours and 8 to 12 hours. Prostatic flu id could be obtained in 10 subjects by prostatic massage 4 hours after drug intake. So as not to contaminate the urethra with ciprofloxacin the subjects were not allowed to void until 4 hours after drug intake. Iopamidol (3.162 gm.), a renal contrast agent, was administered intra venously concomitantly with oral ciprofloxacin intake. After 8 hours i ohexol (3.235 gm.) was administered intravenously. These agents were m easured in prostatic fluid, ejaculate and seminal fluid to assess the contamination of those fluids by urine. All drug measurements were don e by high pressure liquid chromatography. The median plasma concentrat ions of ciprofloxacin were 2.1 mg./l. at 1 hour (maximum concentration ), 0.9 mg./l. at 4 hours and 0.2 mg./l. at 12 hours. The median concen tration in prostatic fluid was 0.23 mg./l. with a fluid-to-plasma conc entration ratio of 0.23. The median concentration in the ejaculate (se minal fluid) after 4 hours was 7.4 mg./l. (6.6 mg./l.) and after 12 ho urs it was 2.0 mg./l. (1.9 mg./l.) with corresponding ejaculate (semin al fluid)-to-plasma concentration ratios of 8.4 (7.7) and 8.0 (6.6), r espectively. Thus, ciprofloxacin is concentrated several-fold in ejacu late and seminal fluid but not in prostatic fluid. According to the re sults the concentrations of ciprofloxacin in prostatic fluid exceed th e minimal inhibitory concentration-90% for Enterobacteriaceae but not for Pseudomonas, enterococci and staphylococci, whereas the concentrat ions in ejaculate and seminal fluid are sufficiently elevated to inclu de the total spectrum of sensitive strains causing bacterial prostatis .