Low-dose oestradiol in the treatment of urogenital oestrogen deficiency--a pharmacokinetic and pharmacodynamic study.

Twenty-four postmenopausal women with vaginal atrophy due to oestrogen deficiency were treated with 17 beta-oestradiol administered as vaginal tablets containing 10 and 25 micrograms, respectively, in a slow-release system (Vagifem, Novo Nordisk, Denmark). All the women were treated for 2 weeks with each dose in a double-blind, cross-over study. Plasma concentrations of unconjugated oestradiol and unconjugated oestrone were measured at regular intervals for 24 h on days 1 and 14 of each treatment regimen. Cytological and clinical evaluations of the vaginal and urethral epithelium were also carried out. Initially, when the epithelium was still atrophic, dose-dependent absorption of oestradiol was demonstrated. After 14 days of treatment maturation of the vaginal epithelium was seen with both regimens and the absorption of oestradiol then declined significantly on both the 10 and the 25 micrograms dose. Oestrone levels remained unchanged and gonadotrophin levels were unaffected during treatment. Vaginal cytology showed maturation on both the 10 and the 25 micrograms dose, whereas urethral cytology showed a reduction in parabasal cells that was significant only on 25 micrograms. Clinical and subjective improvement was apparent on both doses and acceptance of treatment was good.