A synthetic steroid (R2323) as a once-a-week oral contraceptive.

Five milligrams of the steroid R2323 (13 beta-ethyl-17 alpha-ethynyl-17-hydroxygona-4,9,11-trien-3-one (R2323) were administered orally once weekly to 28 subjects for a total of 138 treatment cycles. No pregnancies occurred. The predominant side effects were irregular vaginal bleeding, headache, weight gain, and acne. Administration of the drug was stopped by the investigator in four patients (14%) because of the onset of headaches. Four patients discontinued the drug for other reasons. In 8 of 26 subjects (31%), endometrial biopsy in the third treatment cycle showed secretory endometrium. This suggests a variable central suppression with the 5-mg dose schedule. Patients were enthusiastic about the once-weekly oral administration. This contraceptive may be useful in a select group of women.