indication

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.

biotransformation

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.

absorption

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

half life

5.9 days

drug interactions

Budesonide: CYP3A4 Inhibitors like bicalutamide may increase the serum concentration of budesonide. The clinical significance of this interaction is greater for oral budesonide than for orally inhaled budesonide. Consider reducing the oral budesonide dose when used together with a CYP3A4 inhibitor.

Colchicine: CYP3A4 Inhibitors like bicalutamide may increase the serum concentration of colchicine. Increase monitoring for colchicine-related toxicity when using such combinations. Use extra caution in patients with impaired renal and/or hepatic function.

Eplerenone: CYP3A4 Inhibitors like bicalutamide may increase the serum concentration of eplerenone. A lower starting dose of eplerenone (25 mg once daily) is recommended in patients with hypertension who are also taking drugs that are moderate inhibitors of CYP3A4.

Everolimus: CYP3A4 Inhibitors like bicalutamide may increase the serum concentration of everolimus. Consider therapy modification. Recommendations regarding optimal management of this interaction vary according to specific indication and product used.

Fentanyl: CYP3A4 Inhibitors like bicalutamide may increase the serum concentration of fentanyl. The risk of prolonged adverse effects, including potentially fatal respiratory depression is increased. Consider therapy modification.

Halofantrine: CYP3A4 Inhibitors like bicalutamide may increase the serum concentration of halofantrine. Extreme caution, with possibly increased monitoring of cardiac status (e.g., ECG), should be used with concurrent use of halofantrine with any moderate CYP3A4 inhibitor(s).

Ranolazine: CYP3A4 inhibitors like ranolazine may increase the serum concentration of ranolazine. Consider therapy modification.