 It us added once progression of metastases has occurred following therapy with other interventions such orchiectomy, gonadotropin-releasing hormone modulators, and nonsteroidal antiandrogens.Fosfestrol has also been used to prevent the testosterone flare at the start of gonadotropin-releasing hormone agonist therapy in men with prostate cancer.Fosfestrol sodium is given at a dosage of 600 to 1200 mg/day by slow intravenous infusion over a period of 1 hour for a treatment duration of 5 to 10 days in men with prostate cancer.