Bicalutamide (bicalutamide)

Bicalutamide, a nonsteroidal antiandrogen, is an antineoplastic agent.

Bicalutamide is a nonsteroidal antiandrogen that is structurally and pharmacologically related to flutamide and nilutamide.

Bicalutamide inhibits the action of androgens by competitively blocking nuclear androgen receptors in target tissues such as the prostate, seminal vesicles, and adrenal cortex; blockade of androgen receptors in the hormone-sensitive tumor cells may result in growth arrest or transient tumor regression through inhibition of androgen-dependent DNA and protein synthesis. Bicalutamide is a selective antiandrogen with no androgenic or progestational activity in various animal models. The relative binding affinity of bicalutamide at the androgen receptor is more than that of nilutamide and approximately 4 times that of hydroxyflutamide, the active metabolite of flutamide.

Common pharmacologic therapies for prostate cancer (i.e., gonadotropin-releasing hormone (GnRH) analogs, nonsteroidal antiandrogens) when used as monotherapy initially result in increased serum testosterone concentrations, which may limit the effects of the drugs. Androgen receptors in the hypothalamus are blocked by bicalutamide, which disrupts the inhibitory feedback of testosterone on luteinizing hormone (LH) release, resulting in a temporary increase in secretion of LH; the increase in LH stimulates an increase in the production of testosterone. As GnRH analogs have potent GnRH agonist properties, testicular steroidogenesis continues during the first few weeks after initiating therapy.

However, the combination of orchiectomy or GnRH analog therapy to suppress testicular androgen production and an antiandrogen to block response of remaining adrenal androgens provides maximal androgen blockade. Concomitant administration of antiandrogens such as bicalutamide in patients initiating therapy with a GnRH analog can inhibit initial androgenic stimulation and potential exacerbation of symptoms (e.g., bone pain, urinary obstruction, liver pain, impending spinal cord compression) that may occur during the first month of GnRH analog therapy.

Although the absolute bioavailability is not known, bicalutamide is well absorbed following oral administration. Administration of bicalutamide with food does not affect the rate or extent of drug absorption. Bicalutamide exhibits high protein-binding (96%).

The S (inactive) enantiomer of bicalutamide is metabolized primarily by glucuronidation. The R(active)enantiomer alsoundergoes glucuronidation but is predominantly oxidized to an inactive metabolite followed by glucuronidation. Metabolites are eliminated in the urine or feces.

The S-enantiomer undergoes rapid clearance in comparison to the R-enantiomer; the R-enantiomer accounts for the majority of steady-state plasma levels (99%). In healthy males, the half-life of the R-enantiomer ofbicalutamide is approximately 5.8 days.

USES: Bicalutamide is used to treat prostate cancer. This medication works by blocking the action of hormones in the prostate, slowing the growth of cancer cells. This medication should not be used in women and children.

Generic name: bicalutamide
Pronunciation: (BYE-ka-LOO-ta-mide)

The following indications are listed for Bicalutamide:

• Metastatic Prostate Carcinoma

Also known as: Metastatic Malignancy Of Prostate, Metastatic Malignant Neoplasm Of Prostate, Metastatic Malignant Tumor Of Prostate, Metastatic Prostate Cancer.

No ICD codes are available for this drug.