Effect of low dose cyproterone acetate on the response of acne to isotretinoin.

Twenty-seven males with severe acne were treated for 12 weeks with 0.05 mg/kg/day isotretinoin (ten patients) or 5 mg daily cyproterone acetate (eight patients) or both drugs together in these doses (nine patients). With isotretinoin, the sebum excretion rate (SER) fell by 45% +/- 9% s.e.m. (P less than 0.0025), lesion count fell by 65% +/- 10% (P less than 0.0005) and median clinical 17% +/- 12% (NS) fall in SER, a 15% +/- 10% (NS) fall in lesion count and the median severity was unchanged. Patients unchanged. Patients treated with both drugs showed a 42% +/- 13% reduction in SER (P less than 0.005), a 68% +/- 11% decrease in lesion count (P less than 0.0005) and a decrease in median severity from 8 to 4 (P less than 0.01) which was no different from the response to isotretinoin alone. Isotretinoin increased serum cholesterol from 4.4 mmol/l +/- 0.3 s.e.m. to 4.7 mmol/l +/- 0.3 s.e.m. (P less than 0.01), serum triglyceride from 0.73 mmol/l +/- 0.07 s.e.m. to 0.96 mmol/l +/- 0.14 s.e.m. (P less than 0.05) and gamma-glutamyltransferase (GGT) from 15.9 i.u./l +/- 2.1 s.e.m. to 19.0 i.u./l +/- 2.4 s.e.m. (P less than 0.01). Comparison of the area under the concentration-time curve for triglyceride and high density lipoprotein (HDL)-cholesterol showed that the changes were smaller when isotretinoin was combined with cyproterone acetate. We conclude that the effect of isotretinoin in acne was not enhanced by the antiandrogen, but the increase in serum triglyceride and decrease in HDL-cholesterol produced by the retinoid were reduced by combination with the antiandrogen.