Drug Groups

approved

Description

An antiandrogen with about the same potency as cyproterone in rodent and canine species.

Indication

For the management of locally confined Stage B2-C and Stage D2 metastatic carcinoma of the prostate

Pharmacology

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.

Toxicity

In animal studies with flutamide alone, signs of overdose included hypoactivity, piloerection, slow respiration, ataxia, and/or lacrimation, anorexia, tranquilization, emesis, and methemoglobinemia.

Affected Organisms

Biotransformation

Flutamide is rapidly and extensively metabolized, with flutamide comprising only 2.5% of plasma radioactivity 1 hour after administration.

Absorption

Rapidly and completely absorbed.

Half Life

The plasma half-life for the alpha-hydroxylated metabolite of flutamide (an active metabolite) is approximately 6 hours.

Protein Binding

94-96%

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.

References

External Links