8. Tamoxifen for the treatment of etonogestrel implant associated bleeding in an adolescent gynecology practice

Abstract

<h3>Background</h3> The majority of early etonogestrel (ENG) implant removals occur in the first 12 months after placement and the most common reason for discontinuation is unscheduled and bothersome bleeding. Approximately 65% of adolescent patients with bothersome bleeding receive medication management to address this side effect. Recent studies on adult ENG implant users suggest that a 7-day treatment course of tamoxifen reduces unscheduled bleeding over placebo. Because bothersome bleeding is a common complaint that results in discontinuation of the ENG contraceptive implant, it is important to find safe and effective therapies in the adolescent gynecology population. The goal of this study is to describe outcomes in a cohort of adolescents using tamoxifen to address bothersome implant bleeding. <h3>Methods</h3> A retrospective chart review was performed on adolescent patients ages 12-21 who were seen at Children's Hospital Colorado between 8/2016 – 8/2019 with an ENG implant in place and a prescription for tamoxifen 10 mg twice daily for 7 days given for the indication of implant-associated bleeding. De-identified demographic, clinical, and prescription data was abstracted and stored in a secure REDCAP database. REDCAP data was exported into Stata 16 for analysis, including descriptive statistics and survival analysis using Kaplan Meier curve. IRB approval was obtained from the University of Colorado Anschutz (#20-2349). <h3>Results</h3> A total of 67 patients met inclusion criteria. For those with follow-up data, the continuation rates for the ENG implant were 86% at 12 months, 65% at 24 months, and 44% at 36 months. The average time from implant insertion to initial tamoxifen prescription was 9.3months (± 7.9) with 69.1% (n=47) of patients presenting with symptoms of recurrent bleeding within one year. The average time from tamoxifen prescription to repeat patient visit/call was 3.9mo (± 4.9), while the average time from tamoxifen prescription to implant removal was 12.1mo (± 11.0). Among those who discontinued the implant (n=29), bleeding was the primary reason for discontinuation (66.7%; n=24). No side effects from tamoxifen use were reported. <h3>Conclusions</h3> In this retrospective chart review of 67 adolescents prescribed tamoxifen to manage to bothersome implant bleeding, continuation rates for the ENG implant were comparable or higher than continuation rates reported in the literature. Tamoxifen was well-tolerated among this cohort of patients without any adverse effects reported. Future studies are needed to determine efficacy of tamoxifen compared to other treatments for management of bleeding in adolescent ENG users.