Concentrations of cefpodoxime in plasma, ejaculate and in prostatic fluid and adenoma tissue

Summary Twenty-four healthy volunteers and 24 patients undergoing transurethral resection of the prostate received an oral dose of 200 mg of cefpodoxime as proxetil ester in a fasting state. At the same time 3.235 g of iohexol, a renal contrast medium, was injected intravenously to indicate possible urinary contamination of the prostatic fluid. The subjects were divided into three groups each. After 3, 6 and 12 h the cefpodoxime concentrations were measured in plasma, urine, prostatic fluid and ejaculate in volunteers and in plasma, prostatic fluid and prostatic adenoma tissue in patients by a bioassay as well as by an HPLC method. In general, the concentrations measured by bioassay were higher than those by HPLC. The median plasma concentrations (bioassay) in volunteers (patients) after 3, 6 and 12 h were 2.28 (2.34) mg/l, 0.95 (1.17) mg/l and 0.12 (0.28) mg/l, respectively. The median ejaculate concentrations after 6 and 12 h were 0.95 mg/l and 0.19 mg/l, respectively. Only in three volunteers and in one patient prostatic fluid concentration without urinary contamination could be measured after 3 h with a median fluid to plasma ratio of 0.10. The prostatic adenoma tissue concentrations (bioassay) after 3 and 6 h were 0.50 mg/kg and 0.24 mg/kg with tissue to plasma ratios of 0.30 and 0.26, respectively. After 3 h about half of the volunteers and after 12 h about half of the patients showed no detectable concentration in ejaculate (volunteers) and prostatic tissue (patients), respectively. It was concluded that the cefpodoxime should be administered 3 to 6 h prior to surgery if used for perioperative prophylaxis. The concentration in seminal but not in prostatic fluid is high enough for effective treatment.