Bicalutamide — Drug Monograph

Brand names: Casodex

Drug class: Hormonal Agent

Mechanism of Action

Bicalutamide is a first-generation non-steroidal androgen receptor (AR) antagonist. It competitively inhibits the action of androgens (testosterone and dihydrotestosterone) by binding to the cytosol AR in target tissues, such as the prostate. This prevents the activation of the receptor and subsequent gene expression required for tumor growth. In contrast to second-generation agents, bicalutamide may have partial agonist activity in certain contexts and is less potent.

FDA Indications

• Use in combination therapy with a luteinizing hormone-releasing hormone (LHRH) analog for the treatment of Stage D2 metastatic carcinoma of the prostate

Common Side Effects

• Hot flashes
• Pain (generalized)
• Gynecomastia
• Breast tenderness
• Back pain
• Constipation
• Nausea
• Pelvic pain

Clinical Pearl

Bicalutamide is now primarily used for the first 1–4 weeks of LHRH agonist therapy to prevent "tumor flare." It is rarely used as long-term monotherapy or even as the primary antiandrogen in metastatic disease anymore, having been largely superseded by enzalutamide, apalutamide, and darolutamide. Note the risk of gynecomastia and breast pain, which occurs because bicalutamide increases circulating testosterone and estrogen levels (when used as monotherapy, though less so with GnRH analogs). If…

Related Therapies & Mechanisms

• Abiraterone Acetate (Zytiga) — Hormonal Agent · Prostate
• Apalutamide (Erleada) — Hormonal Agent · Prostate
• Darolutamide (Nubeqa) — Hormonal Agent · Prostate
• Degarelix (Firmagon) — Hormonal Agent · Prostate