Abiraterone Side Effects and Management

Introduction to Abiraterone Side Effects

The National Comprehensive Cancer Network recommends monitoring blood pressure, potassium, and liver function monthly in patients taking abiraterone due to the risk of mineralocorticoid excess side effects, including hypertension, hypokalemia, and peripheral edema 1, 2

Abiraterone inhibits CYP17A, leading to accumulation of mineralocorticoid precursors and causing ACTH-driven mineralocorticoid excess, which explains the characteristic side effect profile and the need for concurrent glucocorticoid therapy 3, 4, 5
Hypertension occurs in 22% of patients overall, with severe hypertension (grade 3-4) in 4-15.5% 1
Hypokalemia affects 17% of patients, with grade 3-4 events in 7-12% 1
Peripheral edema occurs in 28% of patients 1
Fatigue is the most common adverse reaction at 39% 1

Atrial fibrillation occurs in 4% of patients 1
Cardiac disorders lead to discontinuation in 19% of patients, with serious events in 6% 1
Liver function abnormalities are more common in the abiraterone group, with grade 3-4 events requiring monitoring 3, 4
Monthly monitoring of blood pressure, serum potassium, serum phosphate, and liver function tests is essential 1, 2

The National Comprehensive Cancer Network recommends mandatory concurrent steroid therapy, such as prednisone 5 mg orally twice daily, to prevent ACTH-driven mineralocorticoid excess 1, 2
Spironolactone should not be used as it interferes with abiraterone's mechanism of action 6, 7
Dose modifications, such as switching to dexamethasone or lowering the abiraterone dose, may be necessary for toxicity management 1, 2, 8, 9

The fine-particle formulation shows similar adverse event rates to the original formulation, though musculoskeletal disorders occur less frequently (12.5% vs 37.9%) 1, 9
Grade 3-4 mineralocorticoid-related adverse events and liver abnormalities are more common with abiraterone than placebo, but the agent is generally well-tolerated when properly monitored 3, 4