Bicalutamide

Key facts

• Bicalutamide (the active ingredient in Casodex and generics) is a non-steroidal anti-androgen used in prostate cancer, usually alongside a GnRH-analogue injection (combined androgen blockade) or with radiotherapy.
• It is taken once daily as a tablet, with or without food, often for months or years depending on the stage of the cancer.
• Bicalutamide can cause serious, occasionally fatal, liver injury; blood tests to check liver function are recommended before treatment starts and periodically during it.
• Seek urgent care for yellowing of the skin or eyes, dark urine, unexplained nausea, or new breathlessness.

What bicalutamide treats

Bicalutamide treats prostate cancer. In locally advanced disease it is combined with radiotherapy or a GnRH-analogue such as goserelin or leuprorelin as part of combined androgen blockade; in metastatic disease it is used alongside a GnRH-analogue to blunt the testosterone surge these injections cause when started. It is not an established treatment for hirsutism, breast conditions, or cancers outside the prostate.

How bicalutamide works

Prostate cancer cells often depend on androgens, chiefly testosterone and dihydrotestosterone, to grow. Bicalutamide attaches to the androgen receptor inside these cells and blocks the hormones from activating it, without switching the receptor on itself. Starving the tumour of androgen signalling slows its growth.

Before you take it

• Bicalutamide is not used in women, and should be avoided in men with severe liver impairment.
• Tell your prescriber about any liver disease and about all your other medicines; bicalutamide can raise blood levels of warfarin and other drugs cleared by the same liver enzymes.
• Baseline and periodic liver function tests are standard practice; report unexplained tiredness, nausea, abdominal pain or dark urine promptly.
• Because it blocks testosterone's effects, expect breast tenderness and enlargement and hot flushes; ask your oncologist about preventive breast irradiation if this concerns you.

Side effects

Common effects include hot flushes, breast tenderness or enlargement, and tiredness.

Stop and seek urgent medical care for:

• Yellowing of the skin or eyes, dark urine, or pale stools.
• Sudden breathlessness, cough or chest pain, since rare lung inflammation has been reported.
• Signs of an allergic reaction such as facial swelling or difficulty breathing.

Safety essentials

• Liver function tests are part of routine monitoring with bicalutamide because it can cause serious, rarely fatal, liver damage; treatment is usually stopped if significant liver injury develops.
• Bicalutamide does not replace the GnRH-analogue injection it is usually paired with; do not stop either medicine without talking to your oncologist.
• Report new breathlessness or cough promptly, since rare lung inflammation has been linked to bicalutamide.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.