Antiandrogens

Antiandrogens

Antiandrogens are used as an adjunct therapy with gonadotropin-releasing hormone analogues in treating advanced prostate can-cer. These drugs include:

·                 flutamide

·                 nilutamide

·                 bicalutamide.

Pharmacokinetics

After oral administration, antiandrogens are absorbed rapidly and completely.

Metabolism and excretion

Antiandrogens are metabolized rapidly and extensively and ex-creted primarily in urine.

Pharmacodynamics

Flutamide, nilutamide, and bicalutamide exert their antiandrogenic action by inhibiting androgen up take or preventing androgen binding in cell nuclei in target tissues.

Pharmacotherapeutics

Antiandrogens are used with a gonadotropin-releasing hor-mone analogue, such as leuprolide, to treat metastatic prostate cancer.

Special feature: no flareup

Concomitant administration of antiandrogens and a gonadotropin-releasing hormone analogue may help prevent the disease flare that occurs when the gonadotropin-releasing hormone analogue is used alone.

Drug interactions

Antiandrogens don’t interact significantly with other drugs. How-ever, flutamide and bicalutamide may affect prothrombin time (a test to measure clotting factors) in a patient receiving warfar (See Adverse reactions to antiandrogens.)