[Serum concentrations of flutamide and goserelin in a prostate cancer patient with obstructive nephropathy: a case report].

A 72-year-old man presented with pollakiuria and dysuria. His prostate was the size of an apple and hard on digital rectal examination and the serum prostate specific antigen (PSA) level was 73 ng/ml (RIA). Ultrasonography revealed bilateral hydronephrosis and the serum creatinine level was 13.2 mg/dl. CT scanning of the abdomen demonstrated swelling of paraaortic lymph nodes. Transrectal needle biopsy of the prostate gave a diagnosis of moderately differentiated adenocarcinoma. Accordingly, the final diagnosis was prostate cancer (cT3N4M1, stage D2). Immediately after bilateral percutaneous nephrostomy, treatment with an LH-RH agonist (goserelin) and flutamide was commenced. Serum creatinine was 6.6 mg/dl at the start of antiandrogen therapy and decreased to 1.8 mg/dl after 27 days. A 125 mg flutamide capsule was administered at 7 a.m., and blood samples were collected 4 hours later on days 1, 2, 3, 5, 6, 8, 12, 14, 17, 18 and 27. The OH-flutamide concentration was measured. There was no significant correlation between serum creatinine and the OH-flutamide concentration. After implantation of goserelin (3.6 mg depot), blood samples were obtained at 11 a.m. on days 8, 12, 14, 15 and 25. The serum goserelin level was measured. The serum goserelin level increased to a peak on day 14, as described previously, but the peak value of 9.63 ng/ml was higher than that reported before (mean +/- SD 2.848 +/- 0.199).