Active ingredient: Bicalutamide - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

• Antineoplastic Agents

Dosage Forms

• Tablet

Brands / Synonyms

Bicalutamide; Bicalutamide [Usan:Ban:Inn]; Casodex; Casodex

Indications

For treatment (together with surgery or LHRH analogue) of advanced prostatic cancer.

Pharmacology

Bicalutamide is an antineoplastic hormonal agent primarily used in the treatment of prostate cancer. Bicalutamide is a pure, nonsteroidal anti-androgen with affinity for androgen receptors (but not for progestogen, estrogen, or glucocorticoid receptors). Consequently, Bicalutamide blocks the action of androgens of adrenal and testicular origin which stimulate the growth of normal and malignant prostatic tissue. Prostate cancer is mostly androgen-dependent and can be treated with surgical or chemical castration. To date, antiandrogen monotherapy has not consistently been shown to be equivalent to castration.

Mechanism of Action

Bicalutamide competes with androgen for the binding of androgen receptors, consequently blocking the action of androgens of adrenal and testicular origin which stimulate the growth of normal and malignant prostatic tissue.

Absorption

Bicalutamide is well-absorbed following oral administration, although the absolute bioavailability is unknown.

Toxicity

Not Available

Biotrnasformation / Drug Metabolism

Bicalutamide undergoes stereo specific metabolism. The S (inactive) isomer is metabolized primarily by glucuronidation. The R (active) isomer also undergoes glucuronidation but is predominantly oxidized to an inactive metabolite followed by glucuronidation.

Contraindications

CASODEX is contraindicated in any patient who has shown a hypersensitivity reaction to the drug or any of the tablet's components.

CASODEX is not indicated in women. Further, CASODEX is contraindicated in women who are or may become pregnant. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus. CASODEX may cause fetal harm when administered to pregnant women. The male offspring of rats receiving doses of 10mg/kg/day (plasma drug concentrations in rats equal to approximately 2/3 human therapeutic concentrations*) and above were observed to have reduced anogenital distance and hypospadias in reproductive toxicology studies. These pharmacological effects have been observed with other antiandrogens. No other teratogenic effects were observed in rabbits receiving doses up to 200mg/kg/day (approximately 1/3 human therapeutic concentrations*) or rats receiving doses up to 250 mg/kg/day (approximately 2 times human therapeutic concentrations*).

*Based on a maximum dose of 50 mg/day of bicalutamide for an average 70 kg patient.

Drug Interactions

In vitro studies have shown CASODEX can displace coumarin anticoagulants, such as warfarin, from their protein-binding sites. It is recommended that if CASODEX is started in patients already receiving coumarin anticoagulants, prothrombin times should be closely monitored and adjustment of the anticoagulant dose may be necessary.