[bobie]

Antiandrogen type

The use of spironolactone as an antiandrogen seemed also to be associated with an increased incidence of breast augmentation in transwomen. The other, more specific antiandrogens and GnRH analogs were not. Spironolactone is a mineralocorticoid receptor antagonist that acts as an androgen receptor partial antagonist as well as an estrogen receptor agonist. As such, in addition to blocking the androgen receptor (which is its primary purpose in this situation), it also has a significant estrogenic action at the doses used in transwomen. One can postulate that this could lead to an excessive estrogenic action and consequent poorer breast outcome by the same mechanism as that seen when patients self-medicate with estrogens. It is interesting that the other antiandrogens, cyproterone acetate and finasteride, do not appear to be used more frequently in those requiring breast augmentation compared with controls, suggesting that this is not a class effect of antiandrogens.