Objective: To determine danazol concentrations in the ovary, uterus, and serum during daily vaginal administration of a danazol suppository and to examine its effect on the hypothalamic-pituitary-ovarian axis.

Design: Sampling of tissues after vaginal or oral administration of danazol and sampling of blood during control and danazol-administration menstrual cycles.

Setting: Outpatient volunteers and inpatients at a public hospital.

Participants: Thirty patients who were to undergo hysterectomy and oophorectomy because of uterine leiomyoma and eight regularly menstruating volunteers.

Interventions: Danazol was administered as a vaginal suppository (100 mg) or orally (400 mg).

Main outcome measure: Danazol concentrations in the ovary, uterus, and serum, and serum E2 and P levels.

Results: Danazol concentrations in the ovary and uterus after daily vaginal administration of a suppository containing 100 mg danazol were comparable to those after daily oral administration of 400 mg danazol, but the serum danazol concentration was much lower. Menstrual cycle patterns of serum E2 and P levels were normal during daily vaginal administration of a danazol suppository.

Conclusion: Daily administration of a suppository containing 100 mg danazol produces high ovarian and uterine concentrations but low serum concentrations, and no effect was detected on the hypothalamic-pituitary-ovarian axis.