Prostatic tissue and fluid concentrations of trimethoprim and sulfamethoxazole: experimental and clinical studies.

The concentrations of trimethoprim and sulfamethoxazole were determined in prostatic fluid and tissue of the dog after constant intravenous infusion. Concentrations of trimethoprim in both prostatic fluid and tissue exceeded the simultaneous serum concentrations, whereas the sulfamethoxazole prostatic fluid and tissue concentrations were much lower than the simultaneous serum concentrations. Prostatic tissue obtained from patients undergoing transurethral resection of the prostate also contained trimethoprim in higher but sulfamethoxazole in lower concentrations than the simultaneous serum concentrations after oral administration of these drugs preoperatively. In a patient with urinary diversion, trimethoprim was found in prostatic fluid in concentrations as high as forty-four times the simultaneous serum concentrations whereas sulfamethoxazole was found in concentrations representing only a fraction of the simultaneous serum concentrations. These findings lend support to the use of trimethoprim in the treatment of bacterial prostatitis.