Serious Hypokalemia Associated with Abiraterone Acetate in Patients with Castration-Resistant Prostate Cancer

Figure 3

(a) Steroid biosynthesis pathway under abiraterone monotherapy. Inhibition of 17-alpha-hydroxylase and C17 and 20-xylase result in a decrease of cortisol and a consequent increase in ACTH. Increased ACTH causes hypokalemia, fluid retention, and hypertension as a consequence of deoxycorticosterone excess. (b) Steroid biosynthesis pathway under abiraterone plus dexamethasone. Addition of dexamethasone 0.5mg/dl to abiraterone results in suppression of ACTH and a consequent decrease in deoxycorticosterone that prevents hypokalemia, fluid retention, and hypertension. Downstream steroid levels remain suppressed.

(a)

(b)