Potential negative pharmacodynamic interaction of spironolactone and abiraterone in two prostate cancer patients

Abstract

Introduction Spironolactone when combined with abiraterone in metastatic castration-resistant prostate cancer (mCRPC) may theoretically exert androgenic properties, thereby compromising the therapeutic effectiveness of abiraterone. Case report Two patients with a medical history of cardiovascular disease and mCRPC combined spironolactone within the course of abiraterone regimen. The abiraterone-spironolactone interaction was identified using the Lexicomp® interaction tool (classified as risk C). Management & outcome Spironolactone treatment was maintained as it was considered beneficial due to the cardiac condition. The prostate-specific antigen (PSA) levels started to rise when these two drugs were used together. Eventually, tumour progression was observed. Discussion There is increasing evidence that spironolactone behaves as a selective androgen receptor modulator. Strategies to overcome abiraterone-spironolactone interaction could involve the use of eplerenone, although this drug is also controversial. The best strategy should imply a multidisciplinary evaluation by cardiologists and oncologists.

Remission of progressive metastatic castration-resistant prostate cancer during abiraterone therapy following unilateral adrenalectomy for a functioning adrenal adenoma

“…Several case studies have described the negative effect the combination of spironolactone with abiraterone has on mCRPC. [29][30][31][32] In this case, it is difficult to determine whether the medication combination withdrawal or the adrenalectomy itself is responsible for this patient's response, as spironolactone was discontinued at around the same time as his adrenalectomy. Additionally, serum testosterone levels clearly declined postadrenalectomy, which do not explain the spironolactone effect.…”