Generic Name

Casodex

Mechanism

Bicalutamide competitively binds to the androgen receptor (AR) in prostate epithelial cells, blocking testosterone and dihydrotestosterone (DHT) from activating the receptor. This prevents the transcription of AR‑dependent genes, inhibiting prostate cell proliferation and inducing apoptosis. Unlike some NSAAs, casodex has a high affinity for the AR and does not stimulate the receptor, minimizing the risk of “anti‑androgen withdrawal syndrome.”
• Competitive AR antagonist
• No androgenic or estrogenic activity
• Blocks intraprostatic androgen synthesis indirectly by retro‑statin inhibiting aromatase activity

Pharmacokinetics

Indications

• Localized or metastatic prostate cancer in men with androgen‑dependent disease
• Androgen‑deprivation therapy (ADT) in combination with luteinizing hormone‑releasing hormone (LHRH) agonists or antagonists
• Hormone‑responsive prostate carcinoma in men who are intolerant to other NSAAs
• Non‑invasive post‑operative maintenance to reduce hormone‑driven recurrence

Contraindications

• Contraindications
• Known hypersensitivity to bicalutamide or its excipients
• Active liver disease or unexplained persistent hypertransaminasemia (ALT/AST > 3× ULN)
• Warnings
• Liver toxicity: Monitor liver enzymes (ALT, AST, bilirubin) before therapy and at 6‑week, 12‑week intervals thereafter.
• Gynecomastia: Up to 30% of patients may develop palpable breast enlargement.
• Serum calcium: Rare hypercalcemia reported; monitor if symptomatic.
• Drug interactions: CYP3A4 inhibitors (e.g., ketoconazole, erythromycin) can increase serum levels; adjust dose accordingly.
• Pregnancy: Category X – teratogenic; use effective contraception in men and female partners.

Dosing

• Adult men: 150 mg orally once daily (standard dose); may be titrated up to 200 mg/day for resistance or inadequate response.
• Combination therapy: Use concurrently with LHRH agonist/antagonist (e.g., leuprolide, goserelin) or with 5‑α‑reductase inhibitors.
• Administration advice: Take with food to enhance absorption; avoid large doses of alcohol due to increased hepatic enzyme activity.

Adverse Effects

Common (≥10%)
• Gynecomastia, breast tenderness (5‑30%)
• Hot flashes, flushing
• Nausea, vomiting
• Polyuria, dysuria
• Elevated serum creatinine (minor)

Serious (≤1%)
• Hepatotoxicity (↑ALT/AST > 3× ULN, jaundice)
• Severe gynecomastia with ulceration
• Hypersensitivity reactions (anaphylaxis)
• Interstitial lung disease (rare)

Monitoring

• Baseline: CBC, LFTs, serum electrolytes, fasting lipid profile, pelvic imaging if indicated.
• During therapy:
• LFTs every 6 weeks for the first 6 months, then at 3‑month intervals.
• PSA levels monthly until stabilization, then every 3 months.
• Testosterone to confirm castrate levels (<50 ng/dL).
• Clinical assessment for gynecomastia, signs of liver dysfunction, or drug‑interaction side effects.

Clinical Pearls

• Gynecomastia risk: Occurs dose‑dependently; prophylactic NSAID or tamoxifen therapy is often unnecessary, but early detection and palliative surgical excision can improve patient comfort.
• Bone health: Bicalutamide does not affect bone density; concurrent ADT may necessitate calcium/vitamin D supplementation and DEXA scanning.
• Drug‑interaction vigilance: Concomitant use of CYP3A4 inhibitors can elevate serum levels → potential hepatotoxicity; consider dose reduction or alternative anti‑androgen agents.
• Resistance patterns: Transition to higher doses (200 mg/day) or combine with 5‑α‑reductase inhibitors (finasteride) can overcome mild resistance in metastatic castration‑resistant prostate cancer.
• Pegylated vs. non‑peg: Unlike enzalutamide, casodex has no central nervous system penetration, reducing fatigue and peripheral neuropathy.

--
• *For clinical decision‑making, always cross‑check with current guidelines (e.g., NCCN, EAU) and institutional protocols.*