As an alternative approach to treatment, the patients with familial male precocious puberty were enrolled in protocol 83-CH-0028, "Spironolactone Treatment of Boys with Familial Isosexual Precocious Puberty". Spironolactone (Aldactone) is an antiandrogen that also reduced testosterone synthesis by inhibiting the enzyme 17-hydroxylase. This treatment decreased the plasma testosterone level and inhibited the peripheral effect of testosterone on target tissues. This was apparent through a decrease in acne and in the frequency of spontaneous erections.