RESUMEN
In a multicentre study 882 women were treated during a total of 12,850 cycles with a new combiphasic contraceptive: CTR 24. The study period was 18 cycles. The combiphasic preparation CTR 24 contains 25 micrograms desogestrel (CAS 54024-22-5) plus 40 micrograms ethinylestradiol (CAS 57-63-6) daily for the first 7 days followed by the combination of 125 micrograms desogestrel and 30 micrograms ethinyl-estradiol daily for the subsequent 15 days. The bleeding patterns were analysed over pill cycles and a comparison was made between starters and switchers. The cycle control of the combination was very good. The side effect profile was favourable.
PIP: Physicians recruited 882 women into a multicenter trial of a new biphasic oral contraceptive (OC) (25 mcg + 125 mcg desogestrel and 40 mcg + 30 mcg ethinyl estradiol). Trial sites were in Belgium, Denmark, Finland, France, Germany, Norway, Sweden, and the former Yugoslavia. After 3 cycles, women who had switched from using another OC in the 2 months before the study (switchers) were less likely to continue the new OC than were women who had not used any OC in the last 2 months (starters) (6 cycles = 87.2% vs. 90.6%, 12 cycles = 74.7% vs. 79.5%; and 18 cycles = 59.8% vs. 64.9%). Withdrawal bleeding did not occur in 3.2% of all cycles. Absence of withdrawal bleeding became less common over time (cycle 1 = 7.6%, cycle 3 = 5%, cycle 6 = 3.2%, and cycle 18 = 1.8%). Duration of withdrawal bleeding was no more than 5 days in 80% of all women. More and more women had no more than 5 days of withdrawal bleeding as time passed (cycle 1 = 81.7%, cycle 6 = 85.6%, and cycle 18 = 90.6%). Irregular bleeding was more common in the first cycles of the study than in subsequent cycles (e.g., spotting during cycles 1-3 = 8.5-4.8% vs. 3.7-3.1% during cycles 6-18). By cycle 18, 96% of all women had no irregular bleeding. The drop-out rate for irregular bleeding was 2.2% at the end of the study. In 5% of cycles, at least 1 tablet was forgotten. In the first cycles, starters were somewhat more likely to complain of nausea, headache, and breast tenderness than switchers (e.g., nausea, cycle 1 = 5.8% vs. 3.4%). The gap between the 2 groups disappeared after 3 cycles. Starters were more likely to have minor complaints before OC use than after OC use (e.g., 6.5% fewer frequencies of headaches at 18 months). These findings show that the new OC has very good cycle control and a agreeable side effect profile.