Efficacy and safety of a flexible extended regimen of ethinylestradiol/drospirenone for the treatment of dysmenorrhea: a multicenter, randomized, open-label, active-controlled study

BACKGROUND Dysmenorrhea is a common condition in women, which is characterized by menstrual pain. Low-dose estrogen/progestin combined oral contraceptives have been shown to reduce the severity of dysmenorrhea symptoms, and a 28-day cyclic regimen of ethinylestradiol/drospirenone (28d regimen) is approved for this indication in Japan. AIM The aim of this study was to assess the safety and efficacy of a flexible extended regimen of ethinylestradiol/drospirenone (flexible regimen) in Japanese women with dysmenorrhea. METHODS This multicenter, open-label study was performed in Japanese women with dysmenorrhea who, after a baseline observational phase, were randomized to receive ethinylestradiol 20 μg/drospirenone 3 mg in a flexible regimen (one tablet each day for 24-120 days followed by a 4-day tablet-free interval) or in the standard 28d regimen (one tablet each day for 24 days, followed by 4 days of placebo tablets for six cycles). The primary endpoint was the number of days with dysmenorrhea of at least mild intensity over a 140-day evaluation period. Dysmenorrhea scores, bleeding patterns, and other pain-related parameters were also assessed. RESULTS A total of 216 women (mean age 29.7 years) were randomized to the flexible regimen (n=108) or 28d regimen (n=108) and 212 were included in the full analysis sets (flexible regimen, n=105; 28d regimen, n=107). Women in the flexible-regimen group reported a mean of 3.4 fewer days with dysmenorrheic pain than women in the 28d-regimen group, with similar decreases in disease severity reported in both treatment groups. According to the investigators, 64.8% and 59.4% of women in the flexible-regimen and 28d-regimen treatment groups had "very much improved" or "much improved" disease, while 54.3% and 50.9% of patients reported being "very much satisfied" or "much satisfied" with their treatment, respectively. CONCLUSION In Japanese women with dysmenorrhea, a flexible extended regimen of ethinylestradiol/drospirenone decreased the number of days with dysmenorrheic pain versus the traditional 28d regimen.