Imipenem concentrations in human prostatic tissue: Clinical implications

Chronic bacterial prostatitis is well known for the difficulty of its eradication. The introduction of new chemotherapeutic agents that reach high concentrations in the prostatic tissue is therefore of high clinical interest. Our research group studied imipenem concentrations in plasma urine, and prostatic tissue using an improved high-performance liquid chromatography (HPLC) method. Twenty patients with benign prostatic hypertrophy scheduled for surgery (ten open prostatectomies and ten transurethral resections) were studied. Each patient received two 500-mg doses of imipenem-cilastatin (intravenously [IV] or intramuscularly [IM] within the 12 hours preceding the surgical resection. Samples of plasma, urine, and prostatic tissue were obtained at the operation time. Control samples of plasma and urine were collected before treatment. Observed imipenem HPLC levels were in full agreement with the known pharmacokinetic data and showed a rapid urinary clearance of the molecule, which makes it suitable for the management of urinary infections. Average plasma levels of the drug were higher with IV administration, indicating a slower release from the IM injection site, thus allowing a longer sustained plasma level. Prostatic tissue concentrations were comparable with both administration routes and reached levels higher than MIC90 for most pathogens after only two 500-mg doses of imipenem-cilastatin. Due to the levels reached in prostatic adenomatous tissue, imipenem/cilastatin is also suitable for perioperative antibiotic prophylaxis in urologic surgery.