Conditions: Menstruation Disturbances
Keywords: Contraceptive implant Irregular vaginal bleeding Etonogestrel implant
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 56
Healthy volunteers: no

Brief summary:
The purpose of this study is to study whether a drug called tamoxifen can reduce vaginal bleeding in women who are using the Etonogestrel contraceptive implant.

Detailed description:
Nearly all of the 3 million unintended pregnancies in the United States each year result from inconsistent or non-use of contraception. Increasing use of the most effective methods of contraception will reduce unintended pregnancies and their social, medical and economic consequences. The contraceptive etonogestrel implant (ENG implant) is 20 times more effective at pregnancy prevention than oral contraceptive pills, but it has bleeding side effects that make it unappealing for many women. Tamoxifen, a selective estrogen receptor modulator (SERM) used most commonly for adjuvant treatment of breast cancer, has previously been shown to dramatically reduce bleeding in users of an older levonorgestrel-based contraceptive implant (Norplant tm). It has not been studied in newer progestin-based methods such as the ENG implant. If tamoxifen could stop bleeding in users of the ENG implant, it would give patients and physicians a valuable option for management of progestin-induced irregular bleeding. This research project will test the effectiveness of tamoxifen taken on an as-needed basis to treat abnormal bleeding in ENG implant users. If tamoxifen can be established as an effective treatment for frequent or prolonged bleeding, it will increase the acceptability of the ENG implant, increase its use and reduce unintended pregnancies. This is the first project to evaluate tamoxifen for treatment of unfavorable bleeding in users of the ENG contraceptive implant.

Arms:
arm 1: Participants will be randomized to receive either tamoxifen 10mg twice daily for seven days, or placebo twice daily for seven days, to be started on the third day of an episode of bleeding. arm 2: Placebo tablets twice daily for seven days, to be started on the third day of a bleeding episode.

Interventions: intervention 1: Tamoxifen intervention 2: Placebo
Intervention descriptions: intervention 1: 7 day course of tamoxifen during an episode of irregular vaginal bleeding intervention 2: 7 day course of placebo during an episode of irregular vaginal bleeding

Protocol document: