Implanon: a critical review

Pilot study of a novel, alternative subdermal scapular insertion site for the etonogestrel contraceptive implant

OBJECTIVES

To assess the pharmacokinetics and pharmacodynamics of the etonogestrel (ENG) contraceptive implant when inserted at an alternative scapular site.

STUDY DESIGN

We conducted a pilot study of healthy, reproductive-age females who underwent subdermal insertion of an ENG implant over the inferior edge of the nondominant scapula (scapular insertion). We measured serum ENG levels over 1 year at nine time points. Participants completed questionnaires on insertion site and bleeding side effects. We collected photographs and video recordings of insertion and removal techniques.

RESULTS

We enrolled five participants (as prespecified), their median age was 26.0 years (range: 19.6-30.3), and median body mass index was 25.0 kg/m2 (range: 22.0-28.0). All serum ENG concentrations remained >90 pg/mL and were within the range of published data for arm insertion of ENG implant at all time points. The mean serum ENG level was 511.7 pg/mL (±168.2) at 1 week and 136.6 pg/mL (±21.8) at 12 months. During the first week after insertion, four of five participants noted insertion site pain with a median pain score of 2 (range 1-3), but all noted resolution by week two. Participants reported variable bleeding patterns consistent with standard ENG implant placement. At the end of the study, all participants reported satisfaction with the implant and would recommend scapular insertion to a friend.

CONCLUSIONS

Scapular insertion of the ENG contraceptive implant has similar pharmacokinetics to arm insertion over 1 year of use. This novel, alternative site was well tolerated and demonstrated similar bleeding side effects to standard arm insertion.

IMPLICATIONS

Subdermal scapular insertion of the etonogestrel contraceptive implant demonstrated similar pharmacokinetics to arm insertion over 1 year of use. Our pilot data support scapular insertion as an alternative site for ENG contraceptive implants, which could be beneficial for certain patient populations.

The effect of rifampin on serum etonogestrel concentrations and biomarkers of ovulation among contraceptive implant users: A pharmacokinetic and pharmacodynamic study

OBJECTIVES

Rifampin, a strong CYP3A inducer, is the gold standard for evaluating CYP3A-mediated drug-drug interactions. We aimed to evaluate the pharmacokinetic and pharmacodynamic effects of a short course (2 weeks) of rifampin on serum etonogestrel (ENG) concentrations and serologic measures of ovarian activity (endogenous estradiol [E2] and progesterone [P4]) among ENG implant users.

STUDY DESIGN

We enrolled healthy females using ENG implants for 12 to 36 months. We measured baseline serum ENG concentrations using a validated liquid chromatography mass-spectrometry assay and baseline E2 and P4 concentrations using chemiluminescent immunoassays. After 2 weeks of rifampin 600 mg daily, we repeated ENG, E2, and P4 measurements. We compared pre- and post-rifampin serum measurements using paired Wilcoxon signed-rank tests.

RESULTS

Fifteen participants completed all study procedures. Participants' median age was 28.2 years (range 21.8-34.1), median body-mass index was 25.2 kg/m2 (range 18.9-37.3), and median duration of implant use was 22 months (range 12-32). All participants experienced significant decreases from baseline ENG concentrations (median 164.0 pg/mL [range 94.4-265.0]) to post-rifampin measurements (median 47.8 pg/mL [range 24.7-82.8]) (p < 0.001). Serum E2 concentrations also significantly increased with rifampin exposure (median 73 pg/mL vs 202 pg/mL, p = 0.003); increases in serum P4 concentrations were not statistically significant (p = 0.19). Three participants (20%) experienced increased luteal activity, with one presumptively ovulating post-rifampin (P4 = 15.8 ng/mL).

CONCLUSIONS

With only short exposure to a strong CYP3A inducer, ENG implant users experienced clinically significant decreases in serum ENG concentrations that led to changes in biomarkers indicative of waning suppression of ovulation.

IMPLICATIONS

Even a short, 2-week course of treatment with rifampin places etonogestrel contraceptive implant users at risk for decreased contraceptive efficacy. Clinicians should counsel patients using etonogestrel implants considering any duration of rifampin therapy on the need for backup nonhormonal contraception or the use of an intrauterine device to avoid unintended pregnancies.

Satisfaction With the Use of Subdermal Contraceptive Implant in Women Attending the Specialized Polyclinic Primary Health Care Center in Jeddah City: A Cross-Sectional Study

Background Subdermal contraceptive implants are a convenient method of contraception for many women due to the ease of insertion and removal and because they require less follow-up with their health facility. In addition to the contraceptive benefits, women's satisfaction with such devices is essential, as this can affect their quality of life. This study aims to measure women's satisfaction with the subdermal contraceptive implant, Implanon® (Organon & Co., Jersey City, New Jersey, United States), its main side effects, and reasons for removal.  Methods A cross-sectional study was conducted on women between the ages of 19 and 65 years who visited the Family Planning Clinic at the Specialized Polyclinic Primary Health Care Center in Jeddah, Saudi Arabia, between January 2018 and December 2021. An online questionnaire was distributed to the women who had Implanon inserted and 84 responded. Demographic and contraceptive data were collected, including the dates of insertion and removal of Implanon and side effects experienced while on Implanon.  Results Of the 84 women, 65.84% were satisfied with Implanon, while only 19.04% were unsatisfied with the implant. The most common side effect reported was weight gain (54.76%), followed by menstrual Irregularity. (39.29%). The most common reason for removal was the end of the implant's contraceptive duration (42.86%).  Conclusion Most of the women treated at this primary healthcare clinic were satisfied with Implanon. In addition, most of the women removed the implant only due to its reaching the end of its contraceptive duration despite experiencing side effects, and most women said that they would recommend it to their family and friends.

Effect of Topiramate on Serum Etonogestrel Concentrations Among Contraceptive Implant Users

OBJECTIVE

To evaluate topiramate and etonogestrel pharmacokinetic interactions in contraceptive implant users.

METHODS

We conducted a prospective, noninferiority study with healthy women using etonogestrel implants continuously for 12-36 months. We measured baseline serum etonogestrel concentrations and then began a 6-week titrated topiramate regimen to standard migraine (100 mg/day) and epilepsy (400 mg/day) dosages. We repeated serum etonogestrel concentrations at 3 weeks (100 mg/day), 4 weeks (200 mg/day), and 6 weeks (400 mg/day) of topiramate therapy. We measured etonogestrel using a validated liquid chromatography-tandem, mass-spectrometry assay and tested for noninferiority (less than 30% decrease) in serum etonogestrel concentrations from baseline.

RESULTS

We enrolled 48 total participants; 32 completed 3 weeks, 31 completed 4 weeks, and 27 completed all follow-up visits. Participants' median age was 25.3 years (range 18.3-37.2), median body mass index (BMI) was 25.5 kg/m2 (range 18.7-42.2), and median duration of implant use was 24 months (range 12-36). Median etonogestrel concentrations were 142 pg/mL (range 76.2-771) at baseline, 126 pg/mL (range 72.4-585) at 3 weeks, 119 pg/mL (range 65.6-542) at 4 weeks, and 105 pg/mL (46.2-859) at 6 weeks. The 95% CIs for mean percent change in serum etonogestrel concentrations from baseline were [-37.3%+16.9%], [-45.4%+5.2%], and [-66.8%+24.8%] at 3 weeks, 4 weeks, and 6 weeks, respectively. Excluding one participant who had a serum etonogestrel concentration less than 90 pg/mL at baseline, 30.8% of participants (8/26, 95% CI 14.3-51.8%) had a serum etonogestrel concentration less than 90 pg/mL at 6 weeks.

CONCLUSION

Though only a mild enzyme-inducing antiepileptic drug, concomitant topiramate use led to inferior serum etonogestrel concentrations among implant users, with a significant proportion reaching etonogestrel concentrations below the threshold for ovulatory suppression when taking antiepileptic dosages of topiramate.

FUNDING SOURCE

This study was primarily funded through an Investigator-Initiated Study grant from Merck Sharp & Dohme Corp [MISP#57073]. This work was also supported by NIH/NCATS CTSA Grant Number UL1 TR001082 and NICHD K12 Women's Reproductive Health Research Scholar Program (grant number 5K12HD001271-18).

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT03335163.

Variability in repeat serum etonogestrel concentrations among contraceptive implant users during the steady-release pharmacokinetic period

OBJECTIVE

To assess the variability of repeated measurements of serum etonogestrel concentration among contraceptive implant users.

STUDY DESIGN

We measured 3 consecutive serum etonogestrel concentrations, drawn weekly, in women using etonogestrel implants for 12 to 36 months. We used a repeated measures test to evaluate differences.

RESULTS

Among 20 participants, repeat serum etonogestrel concentrations did not differ from initial measurements (Friedman's test, p = 0.95). Mean serum etonogestrel concentrations had similar 95% confidence intervals at each time point: (134.09, 201.46), (135.08, 237.46), and (132.66, 192.45).

CONCLUSION

We confirm that single-time measurements of serum etonogestrel concentration are acceptable pharmacokinetic outcomes for etonogestrel implant studies.

IMPLICATIONS

Pharmacokinetic studies of the etonogestrel contraceptive implant assume single-time measurements are stable steady-state estimates based on small studies using older analysis methods. Our repeated measures study using modern liquid-chromatography mass-spectrometry analysis methods provides updated support for single-time pharmacokinetic measurements among etonogestrel implant users.

Weight Gain Patterns in Adolescent and Young Adult Women With the Etonogestrel Implant: Comparison by Weight Category

PURPOSE

The purpose of this study was to determine if initiation and use of the etonogestrel implant was associated with differential weight gain in patients who were overweight or obese compared with normal-weight patients.

METHODS

This is a cohort study of 1,024 patients between ages of 13 and 25 years seen in a Title X clinic who received the etonogestrel implant from 2007 to 2019 and had weight measurements at implant insertion and 6-18 months before (preinsertion) and after insertion (postinsertion).

RESULTS

Patients, regardless of weight category (normal weight, overweight, and obese), increased weight in kilograms (kg) from preinsertion to insertion (1.16 ± 4.16 kg, 2.79 ± 5.35 kg, and 4.54 ± 7.71 kg, respectively) and from insertion to postinsertion (1.38 ± 4.37 kg, 2.94 ± 6.97 kg, and 3.66 ± 6.53, respectively). However, there was no increase in the amount gained comparing preinsertion to insertion with insertion to postinsertion. Patients who removed the implant (n = 84) for weight concerns did have increased weight change and a greater percent who gained ≥5% postinsertion as compared with those who removed the implant for other reasons or did not have the implant removed (65.5% vs. 34.2% vs. 39.2%, respectively, p = .03).

CONCLUSIONS

Overweight and obese adolescents are at risk of weight gain over time, but placement of the implant did not accelerate the rate of gain from preinsertion to postinsertion. However, patients who removed the implant specifically because of weight gain did gain more weight after insertion compared with before. Clinicians should help patients evaluate the benefits and risks of highly effective contraceptive options as well as be aware of a subset of patients who do gain weight with use of the implant.

An exploratory study on the association of lifestyle factors with serum etonogestrel concentrations among contraceptive implant users

PURPOSE

To explore how diet and exercise habits associate with serum etonogestrel concentrations among contraceptive implant users.

MATERIALS AND METHODS

We conducted a secondary analysis of healthy, reproductive-age women using etonogestrel implants. This study was registered on ClinicalTrials.gov, NCT03092037. We assessed diet and exercise habits with two validated surveys: Healthy Eating Vital Signs and the Stanford Brief Activity Survey. Participants previously had their serum etonogestrel concentrations measured using a validated liquid-chromatography mass-spectrometry assay. We then used linear modelling to test for associations between survey responses and serum etonogestrel concentrations.

RESULTS

Among 129 participants, diet and exercise habits had no significant associations with serum etonogestrel concentrations (p = 0.22-0.72), with inconsistent effects found for increased caloric intake and sedentary lifestyle.

CONCLUSION

This exploratory study found no significant effect of diet or exercise habits on steady-state pharmacokinetics among contraceptive implant users.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov: NCT03092037.

Safety and Benefits of Contraceptives Implants: A Systematic Review

Progestin-only contraceptive implants provide long-acting, highly effective reversible contraception. We searched the medical publications in PubMed, CENTRAL, and EMBASE for relevant articles on hormonal implants published in English between 1990 and 2021. Levonorgestrel (LNG) 6-capsule subdermal implants represented the first effective system approved for reversible contraception. The etonogestrel (ENG) single rod dispositive has been widely employed in clinical practice, since it is a highly effective and safe contraceptive method. Abnormal menstrual bleeding is a common ENG side effect, representing the main reason for its premature discontinuation. Emerging evidence demonstrated that it is possible to extend the use of the ENG implant beyond the three-year period for which it is approved. The ENG implant could be an effective and discrete alternative to the IUD in young girls, such as post-partum/post-abortion. Implants should be inserted by trained skilled clinicians who previously provide adequate counselling about their contraceptive effect, benefits, and any possible adverse events. More studies are needed to validate the extended use of the ENG implant for up to 5 years.

An exploratory analysis on the influence of genetic variants on weight gain among etonogestrel contraceptive implant users

OBJECTIVE

To identify genetic variants associated with weight gain related to etonogestrel contraceptive implant use.

STUDY DESIGN

We conducted a retrospective analysis from a parent pharmacogenomic study of healthy, reproductive-aged women using etonogestrel implants. We reviewed medical records to calculate objective weight changes from implant insertion to study enrollment and asked participants about subjective weight gain (yes/no) during contraceptive implant use. We used genotyping data (99 genetic variants) from the parent study to conduct backward-stepwise generalized linear modeling to identify genetic variants associated with objective weight changes.

RESULTS

Among 276 ethnically diverse participants, median body-mass index (BMI) was 25.8 kg/m² (range 18.5-48.1). We found a median weight change of +3.2 kg (range -27.6 to +26.5) from implant insertion to study enrollment. Report of subjective weight gain had minimal agreement with measured weight gain during implant use (Cohen's kappa = 0.21). Our final generalized linear model contained two variables associated with objective weight change that met conservative statistical significance (p < 5.0 × 10^-4). Participants with two copies (homozygous) of the ESR1 rs9340799 variant on average gained 14.1 kg more than all other participants (p = 1.4 × 10^-4). Higher enrollment BMI was also associated with objective weight gain (β = 0.54, p = 9.4 × 10^-12).

CONCLUSION

Genetic variants in the estrogen receptor 1 (ESR1) do not have known associations with obesity or metabolic syndrome, but there is physiologic plausibility for a progestin-mediated genetic association between ESR1 and weight gain. Additional genetic research is needed to substantiate our findings and elucidate further advances in individualized counseling on the risk of weight gain with exogenous steroid hormones.

IMPLICATIONS

Genetic variation in the estrogen receptor 1 gene may account for variability in weight gain among etonogestrel contraceptive implant users. If these findings can be replicated with other progestin-containing medications, we may be able to better individualize contraceptive counseling.

Influence of Polymer Composition on the Controlled Release of Docetaxel: A Comparison of Non-Degradable Polymer Films for Oesophageal Drug-Eluting Stents

Following the huge clinical success of drug-eluting vascular stents, there is a significant interest in the development of drug-eluting stents for other applications, such as the treatment of gastrointestinal (GI) cancers. Central to this process is understanding how particular drugs are released from stent coatings, which to a large extent is controlled by drug-polymer interactions. Therefore, in this study we investigated the release of docetaxel (DTX) from a selection of non-degradable polymer films. DTX-polymer films were prepared at various loadings (1, 5 and 10% w/w) using three commercially available polymers including poly(dimethylsiloxane) (PSi), poly (ethylene-co-vinyl acetate) (PEVA) and Chronosil polyurethane (PU). The formulations were characterised using different techniques such as photoacoustic Fourier-transform infrared (PA-FTIR) spectrophotometry, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The effect of DTX on the mechanical properties of the films, in-vitro release, and degradation tests were also assessed. For all polymers and DTX loadings, the drug was found to disperse homogenously without crystallisation within the polymer matrix. While no specific interactions were observed between DTX and PSi or PEVA, hydrogen-bonding appeared to be present between DTX and PU, which resulted in a concentration-dependent decrease in the Young’s moduli of the films due to disruption of inter-polymeric molecular interactions. In addition, the DTX-PU interactions were found to modulate drug release, providing near-linear release over 30 days, which was accompanied by a significant reduction in degradation products. The results indicate that DTX-loaded PU films are excellent candidates for drug-eluting stents for the treatment of oesophageal cancer.

A pilot study on the effect of isotretinoin on serum etonogestrel concentrations in contraceptive implant users

OBJECTIVE

To explore the pharmacokinetic interaction between isotretinoin, a cytochrome P-450 (CYP) inducer and potent teratogen, and the etonogestrel contraceptive implant.

STUDY DESIGN

We enrolled healthy reproductive-age women initiating isotretinoin and using an etonogestrel implant. We compared serum etonogestrel concentrations at baseline and after four and nine weeks of isotretinoin co-administration using a validated assay.

RESULTS

Among eight implant users, all serum etonogestrel concentrations remained >90 pg/mL during isotretinoin co-administration with no significant changes from baseline (p = 0.25, Friedman's test).

CONCLUSION

In this exploratory study, we found that isotretinoin did not cause serum etonogestrel concentrations to fall below the threshold for ovulatory suppression (<90 pg/mL) among implant users.

IMPLICATIONS

Reproductive-age women treated with isotretinoin require reliable contraception to prevent pregnancies impacted by teratogenic-effects. This small study demonstrates that contraceptive implant users maintained serum etonogestrel concentrations above the threshold for consistent ovulatory suppression during isotretinoin co-administration. The contraceptive implant remains an appropriate option for patients considering isotretinoin therapy.

Relationship Between Etonogestrel Concentrations and Bleeding Patterns in Contraceptive Implant Users

OBJECTIVE

To estimate whether serum etonogestrel concentrations influence bleeding patterns and related side effects in contraceptive implant users.

METHODS

We conducted a prospective cross-sectional study with healthy, reproductive-aged women using etonogestrel implants for 12-36 months. Participants completed a brief questionnaire to assess their current bleeding pattern and any experience of abnormal bleeding with the implant. We then measured serum etonogestrel concentrations. We also reviewed the charts of participants to determine whether a prescription for oral contraceptive pills was ever given for treatment of implant-related bothersome bleeding. We performed multivariable logistic regression to test for associations between serum etonogestrel concentrations and both bleeding patterns and related side effects.

RESULTS

We enrolled 350 women, and 59.4% reported having experienced abnormal bleeding with the contraceptive implant. Only 14.9% of participants reported amenorrhea and 37.7% reported monthly periods. Among participants with reviewable medical records (n=253), roughly 20% had received a prescription for oral contraceptive pills during implant use. Increasing serum etonogestrel concentrations were significantly associated with increasing odds of reporting abnormal bleeding (adjusted odds ratio [aOR] 1.005, P=.015) and increasing odds of having received an oral contraceptive pill prescription (aOR 1.008, P=.002). For every 100 pg/mL increase in serum etonogestrel concentration, contraceptive implant users in this study had 1.6 times the odds of reporting abnormal bleeding and 2.3 times the odds of having received a prescription as treatment for bothersome bleeding.

CONCLUSION

We found both objective and subjective evidence that higher levels of progestin from the contraceptive implant were associated with bleeding side effects experienced by women in this study. Pharmacologic variation may influence the side effects women experience with a variety of hormonal contraceptive methods, in turn affecting patient satisfaction and discontinuation rates.

Influence of Genetic Variants on Steady-State Etonogestrel Concentrations Among Contraceptive Implant Users

OBJECTIVE

To identify genetic variants that influence steady-state etonogestrel concentrations among contraceptive implant users.

METHODS

We enrolled healthy, reproductive-age women in our pharmacogenomic study using etonogestrel implants for 12-36 months without concomitant use of hepatic enzyme inducers or inhibitors. We collected participant characteristics, measured serum etonogestrel concentrations, and genotyped each participant for 120 single nucleotide variants in 14 genes encoding proteins involved in steroid hormone (ie, estrogens, progestins) metabolism, regulation, or function. We performed generalized linear modeling to identify genetic variants associated with steady-state etonogestrel concentrations.

RESULTS

We enrolled 350 women, who had a median serum etonogestrel concentration of 137.4 pg/mL (range 55.8-695.1). Our final generalized linear model contained three genetic variants associated with serum etonogestrel concentrations: NR1I2(PXR) rs2461817 (β=13.36, P=.005), PGR rs537681 (β=-29.77, P=.007), and CYP3A7*1C (β=-35.06, P=.025). Variant allele frequencies were 69.4%, 84.9%, and 5.1%, respectively. Our linear model also contained two nongenetic factors associated with etonogestrel concentrations: body mass index (BMI) (β=-3.08, P=7.0×10) and duration of implant use (β=-1.60, P=5.8×10); R for the model =0.17.

CONCLUSION

Only BMI and duration of implant use remained significantly associated with steady-state etonogestrel concentrations. Of the three novel genetic associations found, one variant associated with increased etonogestrel metabolism (CYP3A7*1C) causes adult expression of fetal CYP3A7 proteins and can consequently alter steroid hormone metabolism. Women with this variant may potentially have increased metabolism of all steroid hormones, as 27.8% (5/18) of CYP3A7*1C carriers had serum etonogestrel concentrations that fell below the threshold for consistent ovulatory suppression (less than 90 pg/mL). More pharmacogenomic investigations are needed to advance our understanding of how genetic variation can influence the effectiveness and safety of hormonal contraception, and lay the groundwork for personalized medicine approaches in women's health.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT03092037.

Long-acting reversible contraceptive (LARCs) methods

Unplanned pregnancy (UP) is a public health problem, which affects millions of women worldwide. Providing long-acting reversible contraceptive (LARC) methods is an excellent strategy to avoid or at least reduce UP, because the effectiveness of these methods is higher than other methods, and is indeed comparable to that of permanent contraception. As the initial introduction of the inert plastic intrauterine device (IUD) and of the six-rod implant, pharmaceutical companies have introduced a copper IUD (Cu-IUD), different models of levonorgestrel-releasing intrauterine system (LNG IUS), and one and two-rod implants, which certainly improved women's LARC options. The main characteristic of LARCs is that they provide high contraceptive effectiveness with a single intervention, and that they can be used for a long time. Emerging evidence from the last few years has demonstrated that it is possible to extend the use of the 52 mg LNG IUS and of the etonogestrel-implant beyond five- and three years, respectively, which adds new value to these LARCs.

Relationship between patient characteristics and serum etonogestrel concentrations in contraceptive implant users

OBJECTIVE

To determine whether serum etonogestrel concentrations in contraceptive implant users are associated with certain individual patient characteristics.

STUDY DESIGN

We enrolled reproductive-age women using etonogestrel contraceptive implants between 12-36 months duration and measured a single serum etonogestrel concentration. Participants also completed a questionnaire about demographics.

RESULTS

We enrolled 350 participants; median age was 22.5 years (range 18.0-39.1), median months of implant use was 26.0 (range 12.0-36.0), and median body mass index was 25.7 kg/m² (range 18.5-52.0). Our study population was primarily white/Caucasian (46.6% [163/350]) and Hispanic/Latina ethnicity (51.4% [180/350]). The median serum etonogestrel concentration was 137.4 pg/ml and etonogestrel concentrations varied 12.4 fold in the population (range 55.8-695.1 pg/ml). Using forward stepwise linear regression, months of implant use (β=-1.74, p<.001) and body mass index (β=-3.10, p<.001) were both significantly associated with decreased serum etonogestrel concentration with Black/African American race as a positive effect modifier (β=18.24, p=.099); R-squared for the model=0.13.

CONCLUSIONS

Individuals demonstrated a wide variability in serum etonogestrel concentrations, which can potentially affect side-effect profiles and efficacy. Increasing body mass index and longer duration of implant use were associated with small decreases in serum etonogestrel concentrations, while self-reported Black/African American race was associated with a non-significant increase. Despite these findings, most of etonogestrel variability was unaccounted for, suggesting that other clinical, pharmacologic, and genetic factors contributing to variability in etonogestrel concentrations remain to be determined.

IMPLICATIONS

Although increases in body mass index are associated with lower etonogestrel levels in contraceptive implant users, the majority of women will maintain serum concentrations that consistently suppress ovulation. Furthermore, certain patient characteristics can only explain a small portion (13%) of the variability in serum etonogestrel levels among contraceptive implant users.

Microbial transformation of contraceptive drug etonogestrel into new metabolites with Cunninghamella blakesleeana and Cunninghamella echinulata

Biotransformation of a steroidal contraceptive drug, etonogestrel (1), (13-ethyl-17β-hydroxy-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-3-one) was investigated with Cunninghamella blakesleeana and C. echinulata. Five metabolites 2-6 were obtained on incubation of 1 with Cunninghamella blakesleeana, and three metabolites, 2, 4, and 6 were isolated from the transformation of 1 with C. echinulata. Among them, metabolites 2-4 were identified as new compounds. Their structures were deduced as 6β-hydroxy-11,22-epoxy-etonogestrel (2), 11,22-epoxy-etonogestrel (3), 10β-hydroxy-etonogestrel (4), 6β-hydroxy-etonogestrel (5), and 14α-hydroxy-etonogestrel (6). Compounds 1-6 were evaluated for various biological activities. Interestingly, compound 5 was found to be active against β-glucuronidase enzyme with IC₅₀ value of 13.97±0.12μM, in comparison to standard compound, d-saccharic acid 1,4-lactone (IC₅₀=45.75±2.16μM). Intestinal bacteria produce β-glucuronidase. Increased activity of β-glucuronidase is responsible for the hydrolyses of glucuronic acid conjugates of estrogen and other toxic substances in the colon, which plays a key role in the etiology of colon cancer. Inhibition of β-glucoronidase enzyme therefore has a therapeutic significance. Compounds 1-6 were also found to be non cytotoxic against 3T3 mouse fibroblast cell lines.

Effects of etonogestrel treatment in the reproductive organs and uterine arteries of nonoophorectomized guinea pigs

The endometria of women treated with long-term progestin-only contraceptives (LTPOCs) display abnormally enlarged, fragile blood vessels, decreased endometrial blood flow, oxidative stress, and unpredictable focal abnormal endometrial bleeding. Because human studies on the effects of LTPOC treatment are constrained for ethical and practical reasons, we assessed the suitability of nonoophorectomized guinea pigs (GPs) to best mimic the hormonal milieu of women. The present study demonstrates that treatment of GPs parallels the morphological changes following LTPOC treatment of the human endometrium and ovaries. Specifically, treatment resulted in larger hyperemic, uteri compared with controls. Histopathologic and immunohistochemical analysis demonstrated fewer endometrial glands, decreased luminal mucus, increased numbers of blood vessels, and focal hemorrhage. While increased staining for the cell mitosis marker, Ki67, was present in the zona functionalis, no such increase occurred in the basalis. Lastly, effects on vasomotor features of uterine arteries suggest changes that favor increased resistance and reduced blood flow promoting decreased ability to withstand elevations in transmural pressure.

Etonorgestrel concentrations in morbidly obese women following Roux-en-Y gastric bypass surgery: three case reports

BACKGROUND

Pregnancy should be avoided for 12 to 18 months after Roux-en-Y gastric bypass (RYGB) surgery. The etonorgestrel (ENG)-releasing implant (Implanon®) may represent a safe and effective contraceptive method in morbidly obese women who are candidates for bariatric surgery. In addition, the subcutaneous delivery of steroid is unaffected by malabsorptive surgery.

METHODS

Three cases of young women with ENG-releasing implant are reported. The device was inserted 1-2 months prior to RYGB.

RESULTS

Their initial weights were 130 to 176 kg, and the mean weight loss was 33.6 kg at 6 months. The concomitant serum ENG concentrations decreased currently with weight loss but remained above the minimum concentration required for effective contraceptive effect of the implant for at least 6 months following RYGB (average, 170 pg/mL). The concentrations observed before weight loss were lower than in normal-weight women, but decreases in ENG concentrations following implant insertion were similar.

CONCLUSION

These unique data in morbidly obese women highlight the need for further pharmacokinetic studies of contraceptive agents in obese women during weight loss.

Long-term progestin-only contraception in humans versus animal models

Abnormal uterine bleeding is the leading indication for discontinuation of long-term progestin-only contraceptives. Histological sections of endometria from long-term progestin-treated patients display abnormally enlarged blood vessels that are prone to bleed in a nonuniform manner. Because it has been complex to attain patients willing to complete long-term studies, and good quality endometrial tissues have proven difficult to obtain, animal models have been used to obviate this problem. In this review, we describe these models including the guinea pig, an animal model we have previously investigated, to assess the mechanisms involved in abnormal uterine bleeding following long-term progestin-only contraception.

Effect of etonogestrel contraceptive implant (Implanon) on portal blood flow and liver functions

BACKGROUND

This study was conducted to evaluate changes in portal blood flow and liver functions among women using Implanon for 2 years.

STUDY DESIGN

Fifty healthy Implanon users were enrolled in this longitudinal study and followed up for 24 months. Portal blood flow, assessed by color Doppler; prothrombin time and concentration; serum albumin; bilirubin; gamma-glutamyl transferase (GGT); alanine aminotransferase (ALT); and aspartate aminotransferase (AST) were measured before and 24 months after insertion.

RESULTS

After 24 months of Implanon insertion, there were no significant changes in portal blood flow, serum albumin, prothrombin time or concentration. However, there was a significant increase in serum levels of total and unconjugated bilirubin and GGT and a significant decrease in ALT and AST levels. All levels, however, remained within the normal range of values.

CONCLUSIONS

Implanon use for 2 years does not seem to influence portal hemodynamics. Changes in serum levels of bilirubin, GGT, ALT and AST are unlikely to be of clinical significance.

Implanon: a new contraceptive implant

Women who cannot use hormonal contraception containing estrogen have a variety of progestin-only contraceptive methods from which to choose. Implanon is a new single-rod progestin-only contraceptive implant that is easily inserted and can remain in place for up to 3 years. It is highly effective with a rapid onset of action and an equally rapid return of fertility once removed. Counseling is important to help women decide if this method is appropriate for their needs.

Nerve injury caused by removal of an implantable hormonal contraceptive

Implanon insertion and removal are relatively uncomplicated procedures in the hands of medical professionals familiar with the technique. However, injury to branches of the medial antebrachial cutaneous nerve during Implanon insertion and removal can result in impaired sensibility, severe localized pain, or the formation of painful neuroma that can be quite devastating to the patient. The best way to avoid injury to the medial antebrachial cutaneous nerve is to better understand its position relative to the standard area of Implanon insertion. In the event that an injury to the nerve is recognized, immediate plastic surgical measures should be undertaken to avoid displeasing sequels of nerve injuries. Therefore, the benefit of this generally well-tolerated, highly effective, and relatively cost-efficient contraception is guaranteed only in the hands of medical professionals familiar with the technique.

Implanon® : difficultés d'insertion et de retrait, échecs contraceptifs

OBJECTIVE

Analysis of the results of a national pharmacovigilance study on Implanon, a contraceptive implant containing 68 mg of etonogestrel.

PATIENTS AND METHODS

This survey concerns cases of pregnancies (contraception failures), of migrations and of insertion or removal problems with Implanon reported to French Regional Drug Pharmacovigilance Centres and to Organon SA between May 2001 and September 2002.

RESULTS

In France, 39 unintended pregnancies were reported over 17 months. The pregnancies were in 77% of cases (N = 30) due to an insertion technique error (implant not found when pregnancy has been diagnosed). For 3 patients (7,6%), pregnancy was due to a failure of etonogestrel contraceptive effect, explained twice by its association with an enzymatic inductor drug. For 4 patients (10%), pregnancy was due to an untimely insertion (insertion after day 5 of menstrual cycle or woman already pregnant). For two patients, no information was available. The incidence of reported pregnancies in France is estimated at 0.359 / 10(3) implants [0.246-0.482], in accordance with a typical Pearl Index of 0.06 [0.04-0.08]. Twenty-eight suspected migrations (N = 11), problems or failures in removal of the implant (N = 11) and insertion difficulties (N = 6) were notified, corresponding to an incidence of 0.257/10(3) implants [0.162-0.363].

DISCUSSION AND CONCLUSION

Occurrence of pregnancy is possible with Implanon, due to errors in the insertion technique (device not really inserted) or to a non-respect of the SPC recommendations (drug-drug interaction or untimely insertion). Insertion problems can lead to localisation problems (implant not visible by X-ray) then needing further tests and even harmful practice (removal under general anaesthesia). That is why a real and strict training is highly recommended to physicians.

Failure of Implanon contraception in a patient taking carbamazepin for epilepsia

Until now, no pregnancies have been reported in association with the implantable hormonal contraceptive Implanon (Organon, Roseland, NJ, USA), resulting in a pearl index of 0. We present a 24-year-old patient who conceived despite the correct application of Implanon for one and a half year. The patient was concurrently taking carbamazepin for epilepsia. Special care should be taken to patients demanding hormonal contraceptives while taking carbamezepin. Even Implanon seems to possibly fail in this combination.