How quickly can bicalutamide (Casodex) begin to reduce Prostate-Specific Antigen (PSA) levels?

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Last updated: June 11, 2025View editorial policy

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From the Research

Bicalutamide (Casodex) typically begins to reduce PSA levels within 2-4 weeks after starting treatment, with significant decreases often observed within the first month. The standard dose is 50 mg daily when used with LHRH agonist therapy, or 150 mg daily when used as monotherapy. The medication works by blocking androgen receptors in prostate cancer cells, preventing testosterone from stimulating cancer growth and PSA production.

Key Points to Consider

  • The rate and extent of PSA reduction vary among patients depending on factors such as cancer stage, prior treatments, and individual response to the medication 1.
  • During treatment, regular PSA monitoring is essential to assess therapeutic effectiveness, typically every 3-6 months.
  • Patients should take bicalutamide at the same time each day with or without food and should not stop the medication without consulting their healthcare provider, as sudden discontinuation may lead to disease flare.
  • Side effects may include breast tenderness, hot flashes, and potential liver function changes, which should be monitored during treatment 2, 3.

Important Considerations

  • Some patients may experience a rapid rise in PSA levels after starting bicalutamide, which may be associated with an increase in pain level 4.
  • The most probable explanation for this observation is a very early agonist activation of androgen receptor by bicalutamide.
  • However, this is not a common occurrence and the benefits of bicalutamide in reducing PSA levels and slowing disease progression outweigh the risks for most patients 5, 1.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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