Acne: double blind clinical and laboratory trial of tetracycline, oestrogen-cyproterone acetate, and combined treatment

Abstract

Since the recent introduction of a drug regimen containing 2 mg of the antiandrogen cyproterone acetate and 50 micrograms ethinyl-oestradiol (Diane; oestrogen-cyproterone acetate) several uncontrolled reports have extolled the benefits of this drug. Double blind studies, however, are lacking. Sixty two patients with moderate or moderately severe acne were therefore included in a double blind trial of treatment for six months comparing tetracycline alone, oestrogen-cyproterone acetate alone, and a combination of these agents. Sebum excretion rates and bacterial counts were measured before, during, and after treatment, at the same time as a clinical assessment was made. At six months the acne (as assessed by overall grade) had improved by 68% in the antibiotic treated group and by 74% in the oestrogen-cyproterone treated group. The group given a combination of both agents improved by 82%, which was significantly better (p less than 0.025) than the improvement in the tetracycline treated patients. No significant difference was found between the groups given oestrogen-cyproterone alone and the combined treatment. The sebum excretion rate was suppressed by 25% in the patients in both groups receiving oestrogen-cyproterone but not in the group given antibiotics alone. Oestrogen-cyproterone acetate is as effective as antibiotics in treating acne in women, and adding antibiotics offers no advantage over using oestrogen-cyproterone on its own, although in this study the combination was more effective than tetracycline alone at six months.