The etonogestrel (ENG) contraceptive implant is highly effective and long-acting, but users may experience bothersome unscheduled bleeding (USB). An evidence-based strategy to reduce USB could increase continuation of the implant. The objective of this randomized trial was to determine whether a short course of tamoxifen would reduce bleeding/spotting days and increase satisfaction compared to placebo.METHODS:
Women experiencing frequent or prolonged bleeding with the ENG implant were randomized to receive tamoxifen 10 mg or placebo twice daily for seven days, taken at the onset of an episode of bleeding. Treatment was repeated as needed every 30 days. A text message bleeding diary was completed for 180 days. A sample size of 56 was estimated to detect a difference of 6 days of bleeding per 30 days (estimated 40% reduction) with 80% power. Wilcoxian rank sum test compared bleeding/spotting days between groups. Satisfaction was assessed with visual analog scales.RESULTS:
Tamoxifen subjects reported more baseline USB than placebo (median 23 vs 20 bleeding/spotting days out of 30, respectively). In the 30 days after study drug, tamoxifen users experienced significantly fewer days of bleeding/spotting than placebo (median 6 vs 12 days, P=.05). Duration of amenorrhea after therapy was longer for tamoxifen subjects than placebo (median 30 vs 8 days, P=.03). Satisfaction was higher in the tamoxifen group and side effects were similar.CONCLUSION/IMPLICATIONS:
A 7-day course of tamoxifen was well tolerated and significantly reduced USB compared to placebo. Additional research is needed to determine if tamoxifen treatment can reduce discontinuation for USB.