Comparison of Isotretinoin and Cyproterone Acetate — a Clinical and Laboratory Study

In 1966 Neumann and Elger1 first showed that the anti-androgen cyproterone acetate (CPA) reduced the output of the sebaceous glands of mice. This interested those involved in the treatment of acne. The first regime to be used in women was the ‘reverse sequential’ regime of Hammerstein2 who gave 100mg of CPA from day 5 to day 15 of the cycle and 50μg of oestrogen from day 5 to day 26. This regime was used to ensure that withdrawal bleeding occurred on completion of the cycle, because of the strong progestrogenic effect, and depot storing of this high dose of CPA. This method of treatment was found to be successful, with rates of response of 70 per cent improvement after 3 months of treatment being claimed. However, because of the potent unphysiological effect of this dose of CPA, a lower dose combination preparation was developed as an oral contraceptive with 2mg of CPA and 50μg of ethinyloestradiol (Diane, Schering).