Can bicalutamide (Casodex) cause abdominal pain in an adult male patient with prostate cancer?

Bicalutamide and Abdominal Pain

Yes, bicalutamide can cause abdominal pain, which is listed as a common side effect in the FDA drug label and has been documented in clinical trials. 1

Direct Evidence from FDA Drug Label

The FDA-approved prescribing information for bicalutamide explicitly lists body pain (including back, pelvis, and stomach) as one of the most common side effects of the medication. 1 Additionally, the label warns about serious liver problems that can manifest as right upper stomach pain, along with other symptoms such as jaundice, dark urine, nausea, vomiting, and fever. 1

Clinical Trial Data on Gastrointestinal Effects

Systematic reviews of bicalutamide trials have documented gastrointestinal adverse effects:

• Gastrointestinal pain occurred in 7% of patients receiving combined androgen blockade with nonsteroidal antiandrogens (including bicalutamide) compared to 2% in control groups. 2
• Diarrhea was also more common with bicalutamide (10% vs 2% in controls). 2

Serious Hepatotoxicity as a Cause of Abdominal Pain

The most concerning cause of abdominal pain with bicalutamide is hepatotoxicity, which can range from mild transient elevations in liver enzymes to fulminant hepatic failure. 1, 3

Key Warning Signs Requiring Immediate Evaluation:

• Right upper quadrant abdominal pain
• Jaundice (yellowing of skin/eyes)
• Dark urine
• Nausea and vomiting
• Fever or chills
• Unexplained fatigue 1

Clinical Course of Hepatotoxicity:

A documented case report describes a patient who developed abdominal pain, distension, and tenderness after only 4 days of bicalutamide therapy, which progressed to fulminant hepatotoxicity and multiorgan failure resulting in death within 8 days. 3 While this represents a rare but catastrophic outcome, it underscores the importance of monitoring liver function tests before and during bicalutamide therapy. 3

Clinical Management Algorithm

If a patient on bicalutamide develops abdominal pain:

1. Immediately check liver function tests (ALT, AST, bilirubin, alkaline phosphatase) even if the patient previously tolerated bicalutamide without issues. 1, 3

2. Discontinue bicalutamide immediately if liver function tests are elevated or if clinical signs of hepatotoxicity are present (jaundice, right upper quadrant pain, dark urine). 1

3. Consider alternative antiandrogen therapy such as enzalutamide, which has superior efficacy (median time to progression 15.7 months vs 5.8 months for bicalutamide) and does not carry the same hepatotoxicity risk profile. 4, 5

Important Caveats

• Liver function tests should be monitored before starting bicalutamide and periodically during treatment, as hepatotoxicity can occur even in patients who previously completed courses of therapy without problems. 1, 3

• Abdominal pain may also represent disease progression, as prostate cancer can metastasize to abdominal organs or lymph nodes, so imaging studies may be warranted depending on clinical context. 4

• The combination of bicalutamide with LHRH agonists does not eliminate the risk of these adverse effects. 1