Etonogestrel

Etonogestrel is a steroidal progestin used in hormonal contraceptives. Target: Estrogen Receptor/ERR; Progesterone Receptor Etonogestrel is used as a female contraceptive. Etonogestrel is a progestin or a synthetic form of the naturally occurring female sex hormone, progesterone. Etonogestrel tricks the body processes into thinking that ovulation has already occurred, by maintaining high levels of the synthetic progesterone. This prevents the release of eggs from the ovaries. Etonogestrel binds to the progesterone and estrogen receptors. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Once bound to the receptor, progestins like etonogestrel will slow the frequency of release of gonadotropin releasing hormone (GnRH) from the hypothalamus and blunt the pre-ovulatory LH (luteinizing hormone) surge [1].

References:
[1]. http://www.drugbank.ca/drugs/DB00294

Postpartum weight loss in overweight and obese women using the etonogestrel subdermal implant: a pilot study.[Pubmed:28238839]

Contraception. 2017 Jun;95(6):564-570.

OBJECTIVE: To compare weight loss during the first 6months postpartum in overweight and obese women using the Etonogestrel implant, placed in the immediate postpartum period, with that of controls using nonhormonal contraception, utilizing a pilot design. STUDY DESIGN: Pilot, prospective cohort study. Analysis groups were divided by body mass index (overweight: 25-29.9kg/m(2); Class I Obesity: 30-34.5kg/m(2); Class II Obesity: 35-39.9kg/m(2)) and grouped by use of Etonogestrel implant or nonhormonal contraception for all outcomes. Primary outcome was the proportion of women in each group returning to pregravid weight by 6months postpartum. Secondary outcomes included waist circumference, motivation to lose weight, eating habits, physical activity, feasibility of study procedures and assessment of recruitment potential in the first 6months postpartum. RESULTS: A total of 127 women enrolled between June 2014 and August 2015. Fifty-seven chose the Etonogestrel implant for immediate postpartum contraception while 70 chose nonhormonal contraceptives. Six months after delivery, about half of women in each group returned to within 1.5 kg of pregravid weight (42% Etonogestrel [ENG]-implant vs. 67% nonhormonal methods, p=.19). Retention rates were high with over 75% of total study population providing study data at 6months. Two nonhormonal contraceptive users conceived in the first 4months postpartum. CONCLUSION: No statistical difference in percentage return to pregravid weight was detected between groups, but data suggest that a somewhat lower proportion of implant users lost weight at 6months. Rapid recruitment, high retention and marked acceptance of immediate ENG implant use demonstrate feasibility for a larger, adequately powered trial. IMPLICATIONS: Immediate postpartum insertion of the ENG implant is safe and effective. Study findings suggest modest interference in overweight and obese women's ability to lose gestational weight. If future research demonstrates no statistical difference, increased uptake in immediate implant use should occur in most women, including those who are overweight or obese.

Efficacy and side-effects profile of the ethinylestradiol and etonogestrel contraceptive vaginal ring: a systematic review and meta-analysis.[Pubmed:28256919]

Eur J Contracept Reprod Health Care. 2017 Apr;22(2):131-146.

OBJECTIVE: To assess the efficacy and tolerability (side-effects profile), and compliance of the combined contraceptive vaginal ring (CCVR) compared with combined oral hormonal contraceptives (COC). DATA SOURCES: The PubMed, Embase, POPLINE, Cochrane Central Register of Controlled Trials (CENTRAL), LILACS, ClinicalTrials.gov, Clinical Trials Registry Platform (ICTRP) and CINAHL databases were searched. METHODS OF STUDY SELECTION: Electronic databases were searched for randomised clinical trials comparing the CCVR with COC with a duration of at least 3 months between 01 December and 15 December 2015. The primary outcome was efficacy. The secondary outcomes were compliance, absence of withdrawal bleeding, breakthrough bleeding, nausea and headache. Heterogeneity was assessed using I(2) statistic and Cochran's Q statistic. Results were expressed as odds ratios (OR) with 95% confidence intervals (CIs) using random-effects models or fixed-effects models depending on the heterogeneity. RESULTS: 4368 records were identified, 2844 of which were removed after duplicates and 1524 records were screened. Of these, 1503 were excluded and 21 full text articles were assessed for eligibility. After removing another 7 articles, 14 records were finally included in the qualitative and quantitative analysis. The results show a trend to higher efficacy for the CCVR in preventing pregnancy (Peto OR: 0.52 [95% CI: 0.26-1.04]) and a significantly lower presence of nausea (Peto OR: 0.66 [95% CI: 0.46-0.93]). More cycles were compliant in the CCVR group (Peto OR: 1.22 [95% CI: 1.12-1.32]) and fewer women reported breakthrough bleeding (Peto OR: 0.68 [95% CI: 0.51-0.91]). CONCLUSIONS: Our findings demonstrate that the CCVR is as effective and tolerable as the COC but with a better bleeding profile.

Prolonged use of the etonogestrel implant and levonorgestrel intrauterine device: 2 years beyond Food and Drug Administration-approved duration.[Pubmed:28147241]

Am J Obstet Gynecol. 2017 Jun;216(6):586.e1-586.e6.

BACKGROUND: The subdermal contraceptive implant and the 52-mg levonorgestrel intrauterine device are currently Food and Drug Administration approved for 3 and 5 years of use, respectively. Limited available data suggested both of these methods are effective beyond that time. Demonstration of prolonged effectiveness will improve the cost-effectiveness of the device, and potentially patient continuation and satisfaction. OBJECTIVE: We sought to evaluate the effectiveness of the contraceptive implant and the 52-mg hormonal intrauterine device in women using the method for 2 years beyond the current Food and Drug Administration-approved duration. STUDY DESIGN: We initiated this ongoing prospective cohort study in January 2012. We are enrolling women using the contraceptive implant or 52-mg levonorgestrel intrauterine device for a minimum of 3 and 5 years, respectively (started intrauterine device in >/=2007 or implant in >/=2009). Demographic and reproductive health histories, as well as objective body mass index, were collected. Implant users were offered periodic venipuncture for analysis of serum Etonogestrel levels. The primary outcome, unintended pregnancy rate, was calculated per 100 woman-years. We analyzed baseline demographic characteristics using chi(2) test and Fisher exact test, and compared serum Etonogestrel levels stratified by body mass index using the Kruskal-Wallis test. RESULTS: Implant users (n = 291) have contributed 444.0 woman-years of follow-up. There have been no documented pregnancies in implant users during the 2 years of postexpiration follow-up. Calculated failure rates in the fourth and fifth years for the implant are calculated as 0 (1-sided 97.5% confidence interval, 0-1.48) per 100 woman-years at 4 years and 0 (1-sided 97.5% confidence interval, 0-2.65) per 100 woman-years at 5 years. Among 496 levonorgestrel intrauterine device users, 696.9 woman-years of follow-up have been completed. Two pregnancies have been reported. The failure rate in the sixth year of use of the levonorgestrel intrauterine device is calculated as 0.25 (95% confidence interval, 0.04-1.42) per 100 woman-years; failure rate during the seventh year is 0.43 (95% confidence interval, 0.08-2.39) per 100 woman-years. Among implant users with serum Etonogestrel results, the median Etonogestrel level was 207.7 pg/mL (range 63.8-802.6 pg/mL) at the time of method expiration, 166.1 pg/mL (range 67.9 25.0-470.5 pg/mL) at the end of the fourth year, and 153.0 pg/mL (range 72.1-538.8 pg/mL) at the end of the fifth year. Median Etonogestrel levels were compared by body mass index at each time point and a statistical difference was noted at the end of 4 years of use with overweight women having the highest serum Etonogestrel (195.9; range 25.0-450.5 pg/mL) when compared to normal (178.9; range 87.0-463.7 pg/mL) and obese (137.9; range 66.0-470.5 pg/mL) women (P = .04). CONCLUSION: This study indicates that the contraceptive implant and 52-mg hormonal intrauterine device continue to be highly effective for at least 2 additional years of use. Serum Etonogestrel evaluation demonstrates median levels remain above the ovulation threshold of 90 pg/mL for women in all body mass index classes.

The effect of carbamazepine on etonogestrel concentrations in contraceptive implant users.[Pubmed:28288788]

Contraception. 2017 Jun;95(6):571-577.

OBJECTIVE: The objective was to determine the impact of carbamazepine on the pharmacokinetics and pharmacodynamics of the Etonogestrel contraceptive implant. STUDY DESIGN: We enrolled healthy, reproductive-age women using an Etonogestrel implant for 1-3 years. We measured Etonogestrel levels at baseline and following 3 weeks of coadministered carbamazepine titrated up to 300 mg twice daily. We also evaluated for ovarian follicle-like structures and endometrial thickness using transvaginal ultrasound at the baseline and 3-week visits. RESULTS: We enrolled 13 women; 10 completed study procedures. Participants' mean age was 25.6 years (+/-5.6), mean body mass index was 30.4 (+/-7.3), and median duration of implant use was 23 months (range 15-35). The median Etonogestrel concentrations before and after carbamazepine coadministration were 158.1 pg/mL (range 128-347) and 50.9 pg/mL (range 39-202), respectively (p=.005). In 8 of 10 subjects, the Etonogestrel concentration was below the threshold for ovulatory suppression (<90 pg/mL) after carbamazepine coadministration. The number of ovarian follicle-like structures and endometrial thickness did not significantly change before and after carbamazepine coadministration. CONCLUSIONS: Women using a contraceptive implant experienced significant reductions in Etonogestrel concentrations following coadministration of 600 mg of carbamazepine. We did not find significant pharmacodynamic changes during this abbreviated follow-up period. IMPLICATIONS: Carbamazepine use significantly reduces serum Etonogestrel concentrations in women using an Etonogestrel contraceptive implant, with the majority of participants having Etonogestrel concentrations below the threshold for ovulatory suppression. Our findings suggest that treatment with carbamazepine might increase the risk of pregnancy in Etonogestrel implant users.