Consequences of Different Corticosteroids on Serum Potassium and Prostate-Specific Antigen in Patients Receiving Abiraterone for Castration-Resistant Prostate Cancer: A Retrospective Observational Study

Abiraterone acetate is an androgen synthesis inhibitor approved for the treatment of castration-resistant prostate cancer (CRPC). Although co-administration of either prednisone or prednisolone at 10 mg/d has been recommended to reduce the risk of abiraterone-induced hyperaldosteronism (notably hypokalemia) and to give adjunctive pain relief effects, whether these glucocorticoids can be substituted by dexamethasone remains unknown.

We performed a retrospective review of medical records of patients who were given abiraterone for the treatment of CRPC with either prednisolone (ABI/PSL) 10 mg/d or dexamethasone (ABI/DEX) 0.5 or 1 mg/d between 2014 and 2017 in Juntendo University Nerima Hospital. Demographic and biochemical data including prostate-specific antigen (PSA) level were retrieved from the electronic medical records.

Fifty-three eligible patients (27 in ABI/PSL group and 26 in ABI/DEX group) were extracted from the records. Both groups showed no significant changes in serum potassium level before and after starting treatment. In the ABI/PSL group, 12 patients (46%) showed elevations of PSA and 7 patients (27%) discontinued treatment within 3 months. In contrast, in the ABI/DEX group, only 6 patients (25%) showed elevations of PSA and 3 patients (13%, all were given dexamethasone 1 mg/d) discontinued treatment.

Dexamethasone and prednisolone may be equally effective in preventing abiraterone-induced hypokalemia.

Clinical Medicine Insights. Oncology. 2017 Oct 30*** epublish ***

Masaomi Tatsuzawa, Ryuichi Ogawa, Naoki Kinjo, Soan Kim, Fumitaka Shimizu, Yoshiro Sakamoto, Kazuyo Shimojima, Hirotoshi Echizen, Akihisa Miyazaki

Department of Pharmacy, Juntendo University Nerima Hospital, Tokyo, Japan., Department of Pharmacotherapy, Meiji Pharmaceutical University, Tokyo, Japan., Department of Urology, Juntendo University Nerima Hospital, Tokyo, Japan.