Patient-reported symptom changes after switching from brand-name to generic drospirenone/ethinylestradiol: a single-center observational study in Japan

Generic formulations of drospirenone/ethinylestradiol are considered bioequivalent to their brand-name counterparts; however, some patients perceive symptom changes after switching. This study evaluated patient-reported short-term symptom changes after switching from a brand-name to a generic drospirenone/ethinylestradiol formulation in routine clinical practice. This single-center observational study included women treated for dysmenorrhea who switched from a brand-name to a generic drospirenone (3 mg)/ethinylestradiol (20 µg) formulation between October 2022 and July 2023. During the study period, 83 consecutive women switched to the generic formulation. Eighty-one women (97.6%) completed at least three consecutive treatment cycles and a study-specific, non-validated questionnaire and were included in the analysis, while two women were lost to follow-up. Six predefined symptoms were assessed by comparing symptoms experienced while using the generic formulation with those experienced while using the brand-name formulation after three consecutive treatment cycles. Participants were subsequently followed for one year. Among the 81 participants (mean age, 31.1 ± 7.5 years), the median duration of brand-name formulation use before switching was 30 treatment cycles (interquartile range, 17–55). Fifty-five women (67.9%) reported no symptom changes after switching. No statistically significant differences between improvement and worsening were observed for any of the six symptoms. All 81 participants completed the one-year follow-up; 77 (95.1%) continued the generic formulation and four (4.9%) resumed the brand-name formulation. Most women treated for dysmenorrhea reported no perceived short-term symptom changes after switching from the brand-name to the generic drospirenone/ethinylestradiol formulation, although individual variability was observed. Further prospective studies with longer follow-up using validated patient-reported outcome measures are warranted.