Spironolactone
Oral anti-androgen for adult hormonal acne in women. 50-100mg daily.
Originally a potassium-sparing diuretic, used off-label for hormonal acne in women (and for hirsutism). 50-100mg daily takes 3 months for full effect. Side effects: increased urination, low blood pressure, breast tenderness. Requires periodic potassium and creatinine monitoring.