Drug Interaction Between Bicalutamide and Atorvastatin

Mechanism of Interaction

• Atorvastatin is primarily metabolized by CYP3A4, making it susceptible to interactions with CYP3A4 inhibitors, such as bicalutamide, which can lead to increased plasma concentrations of atorvastatin 1, 2, 3.

Clinical Significance

• The American Heart Association recommends that bicalutamide is listed as a CYP3A4 inhibitor that can affect statin metabolism, including atorvastatin 1, 3.

Potential Consequences

• Increased atorvastatin exposure may lead to an elevated risk of statin-associated adverse effects, including myopathy and rhabdomyolysis (muscle damage) and elevated liver enzymes 4, 5.
• The risk of statin-associated muscle toxicity may be higher in patients with other risk factors 4.

Management Recommendations

• The American Heart Association suggests using the lowest effective dose of atorvastatin when co-administered with bicalutamide, and monitoring liver function tests and creatine kinase levels more frequently during co-administration 4.
• Consider using a statin that is less dependent on CYP3A4 metabolism (such as pravastatin, rosuvastatin, or fluvastatin) if clinically appropriate 1, 3.

Monitoring Parameters

• Monitoring parameters should include creatine kinase levels if muscle symptoms develop, signs and symptoms of myopathy, and lipid levels to ensure therapeutic efficacy of atorvastatin despite the interaction 4.