Differential Effects of Cyproterone Acetate vs Spironolactone on Serum High-Density Lipoprotein and Prolactin Concentrations in the Hormonal Treatment of Transgender Women.

INTRODUCTION: Spironolactone and cyproterone acetate (CPA) are the two main antiandrogen medications used in feminizing hormone therapy in transgender women. Previous studies have suggested that these two agents might have opposite effects on high-density lipoprotein (HDL) level when used in this context, and limited data have suggested CPA increases prolactin more than spironolactone.

AIM: To compare the effects of spironolactone and CPA on HDL and prolactin serum concentrations in transgender women.

METHODS: A retrospective chart review was conducted at three clinical sites in Toronto, Ontario, Canada. Patients were selected if they (i) identified as a transgender woman, (ii) had newly started spironolactone or CPA with estrogen or restarted spironolactone or CPA after a washout period of at least 6 months, and (iii) had not used other antiandrogens within the previous 6 months.

MAIN OUTCOME MEASURES: HDL and prolactin concentrations between the two treatment groups at baseline and at 12 months.

RESULTS: Eighty-two patients were included in the spironolactone group and 31 patients were included in the CPA group. Baseline HDL and prolactin levels were not significantly different between the two groups. At 12 months, HDL increased by 0.10 mmol/L (SD = 0.24) in the spironolactone group but decreased by 0.07 mmol/L (SD = 0.21) in the CPA group (P = .002). The difference remained significant after adjusting for baseline HDL, use of lipid-lowering drugs, and age. The change in prolactin was +3.10 μg/L (SD = 5.70) in the spironolactone group and +11.8 μg/L (SD = 8.63) in the CPA group (P < 0.001). This difference also remained significant after adjusting for baseline prolactin level.

CONCLUSION: These data suggest that spironolactone use in transgender women increases HDL levels and that CPA has the opposite effect. CPA also is associated with a larger increase in prolactin. These factors should be considered when choosing between these two antiandrogen agents.