Abstract
Following the administration of trimethoprim (TMP) by mouth in doses varying from 5.0 to 8.1 mg TMP per kg body weight per 24 hours over a period of 24–48 hours, the concentration was examined in either the prostatic tissue or the prostatic secretion, in a total of 13 patients. A microbiological method was employed to determine the concentration, using B. ptrmilis as test organism. A method of collecting the prostatic secretion was used which excluded the admixture of urine with higher antibiotic content than that of the secretion. Tissue was examined which was obtained both by open and closed (transperineal) biopsy. The concentrations of TMP found in both the secretion and the tissue (9–12 hours after the last administration of TMP) were at a thera-peutically active level (≥MIC × 5) with respect to the majority of those bacteria usually occurring in urinary tract infection.