Medical uses
Prostate cancer
Nilutamide is used in prostate cancer in combination with a gonadotropin-releasing hormone (GnRH) analogue at a dosage of 300 mg/day (150 mg twice daily) for the first 4 weeks of treatment, and 150 mg/day thereafter. It is not indicated as a monotherapy in prostate cancer. Only one small non-comparative study has assessed nilutamide as a monotherapy in prostate cancer.Nilutamide has been used to prevent the effects of the testosterone flare at the start of GnRH agonist therapy in men with prostate cancer. Transgender hormone therapy
Nilutamide has been studied for use as a component of feminizing hormone therapy for transgender women. It has been assessed in at least five small clinical studies for this purpose in treatment-naive subjects. In these studies, nilutamide monotherapy at a dosage of 300 mg/day, induced observable signs of clinical feminization in young transgender women (age range 19–33 years) within 8 weeks, including breast development, decreased body hair (though not facial hair), decreased morning erections and sex drive, and positive psychological and emotional changes. Signs of breast development occurred in all subjects within 6 weeks and were associated with increased nipple sensitivity, and along with decreased hair growth, were the earliest sign of feminization.Nilutamide did not change the size of the prostate gland (which is the same as with high-dosage cyproterone acetate and ethinylestradiol treatment for as long as 18 months), but was found to alter its histology, including increased stromal tissue with a significant reduction in acini and atrophic epithelial cells, indicating glandular atrophy.
Nilutamide monotherapy is known to eventually induce gynecomastia in 40 to 80% of men treated with it for prostate cancer, usually within 6 to 9 months of treatment initiation.Relative to other NSAAs, nilutamide has been uniquely associated with mild and reversible visual disturbances (31–58%) including delayed ocular adaptation to darkness and impaired color vision, a disulfiram-like alcohol intolerance (19%), interstitial pneumonitis (0.77–2.4%) (which can result in dyspnea (1%) as a secondary effect and can progress to pulmonary fibrosis), and hepatitis (1%), and has a higher incidence of nausea and vomiting compared to other NSAAs. The incidence of interstitial pneumonitis with nilutamide has been found to be much higher in Japanese patients (12.6%), warranting particular caution in Asian individuals. There is a case report of simultaneous liver and lung toxicity in a nilutamide-treated patient.There is also a risk of hepatotoxicity with nilutamide, though occurrence is very rare and the risk is significantly less than with flutamide. The incidence of abnormal liver function tests (e.g., elevated liver enzymes) has been variously reported as 2 to 33% with nilutamide. For comparison, the risk of elevated liver enzymes has been reported as 4 to 62% in the case of flutamide. The risk of hepatotoxicity with nilutamide has been described as far less than with flutamide. Fulminant hepatic failure has been reported for nilutamide, with fatal outcome. Between 1986 and 2003, the numbers of published cases of hepatotoxicity for antiandrogens totaled 46 for flutamide, 21 for cyproterone acetate, 4 for nilutamide, and 1 for bicalutamide.