Isotretinoin treatment alters steroid metabolism in women with acne.

The effect of isotretinoin (Roaccutane) on serum steroids and urinary steroid metabolites was investigated in seven female patients receiving the drug for treatment of severe acne over a 16-week period. Serum concentrations of dehydroepiandrosterone sulphate (DHAS), androstenedione (A2), and free androgen index (FAI) were not significantly altered. There was a significant fall in testosterone during treatment and a significant reduction in the 24 h urinary excretion of androsterone, tetrahydrocortisone (THE) and tetrahydrocortisol (THF) from week 8 onwards and for aetiocholanolone and allo-THF from week 12 (P less than 0.05). Although pretreatment levels of urinary steroid metabolites were not abnormal, the ratios of the 5 alpha/5 beta metabolites (androsterone:aetiocholanolone and allo-THF:THF) were at the upper limit of the reference range and were lowered after treatment, suggesting that 5 alpha-reductase activity is sensitive to isotretinoin.