| Indication | For the management of locally confined Stage B2-C and Stage D2 metastatic carcinoma of the prostate |
| Pharmacodynamics | Flutamide is a nonsteroidal antiandrogen. In animal studies, flutamide demonstrates potent antiandrogenic effects. It exerts its antiandrogenic action by inhibiting androgen uptake and/or by inhibiting nuclear binding of androgen in target tissues or both. Prostatic carcinoma is known to be androgen-sensitive and responds to treatment that counteracts the effect of androgen and/or removes the source of androgen, e.g. castration. Elevations of plasma testosterone and estradiol levels have been noted following flutamide administration. |
| Mechanism of action | Flutamide is a nonsteroidal antiandrogen that blocks the action of both endogenous and exogenous testosterone by binding to the androgen receptor. In addition Flutamide is a potent inhibitor of testosterone-stimulated prostatic DNA synthesis. Moreover, it is capable of inhibiting prostatic nuclear uptake of androgen. |
| Absorption | Rapidly and completely absorbed. |
| Volume of distribution | Not Available |
| Protein binding | 94-96% |
| Metabolism | Flutamide is rapidly and extensively metabolized, with flutamide comprising only 2.5% of plasma radioactivity 1 hour after administration. |
| Route of elimination | Flutamide and its metabolites are excreted mainly in the urine with only 4.2% of a single dose excreted in the feces over 72 hours. |
| Half life | The plasma half-life for the alpha-hydroxylated metabolite of flutamide (an active metabolite) is approximately 6 hours. |
| Clearance | Not Available |
| Toxicity | In animal studies with flutamide alone, signs of overdose included hypoactivity, piloerection, slow respiration, ataxia, and/or lacrimation, anorexia, tranquilization, emesis, and methemoglobinemia. |