Compatibility of hypokalaemia caused by low-dose prednisolone plus abiraterone acetate therapy for metastatic castration-resistant prostate cancer

Combination therapy with abiraterone and 5 mg/day of PSL in Japanese patients with mCRPC did not change the incidence of grade ≥ 2 hypokalaemia. However, although not significant, 5 mg/day of PSL demonstrated a decreasing trend in serum potassium levels with a larger degree of change than that of 10 mg/day of PSL. Therefore, the combination of abiraterone and 5 mg/day PSL can be administered to Japanese patients with mCRPC. The patients must be monitored for hypokalaemia through measurement of serum potassium levels and observation of subjective symptoms such as muscle weakness, convulsion etc. In addition, the doctor or the pharmacist must explain these symptoms to the patient and instruct them to consult their medical staff immediately in the event of development of such symptoms.