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At least 109 records · Page 6Linked to original sources
PubMed1995

Clinical trial with Nestorone subdermal contraceptive implants.

The clinical performance and the in vivo release rate of a single 4-cm Nestorone subdermal implant were investigated. Implants manufactured by two different procedures were compared. Volunteers were 70 healthy women of proven fertility. Forty women provided blood samples twice a week in the pretreatment cycle and for 5-6 weeks at 6-month intervals during treatment. Additional control cycles (n = 31) were studied in 19 Copper T users. No pregnancy occurred in 1570 woman-months. Nestorone plasma levels (x +/- S.E.) declined from 112 +/- 8 to 86 +/- 3 pmol/L (Implant A) and from 145 +/- 8 to 57 +/- 5 pmol/L (Implant B) from the first to the 24th month. Progesterone levels were < 9.5 nmol/L in 166 (93%) of 178 blood samplings taken during treatment. Progesterone levels > 16 nmol/L were found in only 7 sampling periods (3.9%) in treated women and in 70 (98.6%) out of 71 control cycles. No ovulation occurred with Nestorone plasma levels above 105 pmol/L. No abnormal changes were observed in plasma lipoproteins or other clinical chemistry parameters during treatment. The implants were well tolerated. The most frequent complaint was the occurrence of irregular bleeding. Enlarged follicles found during pelvic examination in 8 subjects (11.4%) disappeared spontaneously in 10 days to 6 weeks. Implants were removed because of medical (n = 10, 14.3%) or personal reasons (n = 6, 8.6%) or at the 24th month of treatment (n = 54, 77.1%). The estimated average daily in vivo release rate of Nestorone was 45-50 micrograms/day. A single Nestorone subdermal implant affords efficient contraceptive protection during two years.

Adolescent↗
PubMed1992

Evaluation of a 1-year levonorgestrel-releasing contraceptive implant: side effects, release rates, and biodegradability.

OBJECTIVE: To determine the release rates, effects on ovulation, and side effects of two lengths of a biodegradable, subdermal contraceptive implant containing levonorgestrel in a caprolactone capsule. DESIGN: Phase II randomized clinical trial. SETTING: Public family planning clinic at an urban general hospital. PARTICIPANTS: Forty-eight healthy, parous, ovulating volunteers. INTERVENTION: Subjects were randomly assigned either a 2.5- or a 4.0-cm contraceptive capsule that was worn under the skin of the upper arm for 1 year if not removed earlier for other reasons. MAIN OUTCOME MEASURES: Serum concentrations of levonorgestrel, progesterone, estradiol, and lipoproteins were measured as were metabolic parameters. Vaginal bleeding and other side effects were recorded. After implant removal, remaining levonorgestrel, capsule viscosity, and molecular weight were measured. RESULTS: The 4-cm implant provided serum concentrations of levonorgestrel ranging from 0.65 ng/mL shortly after insertion to 0.20 ng/mL at 12 months, but the 2.5-cm implant resulted in levels too low for contraception. The 4-cm implant suppressed ovulation in approximately 80% of cycles over 1 year of use, but the 2.5-cm implant failed to suppress ovulation. The implants were rapidly and easily inserted and removed. They retained structural integrity through 1 year of use. Of 48 subjects, 32 had abnormal bleeding patterns; the mean number of days of bleeding per month was 7 with 23 days between episodes. Women using capronor maintained normal metabolic parameters except that low-density lipoprotein decreased slightly. CONCLUSIONS: The 4.0-cm implant is a promising contraceptive. There were no important metabolic effects, but there were bothersome minor side effects typical of progestin-only contraception.

Abdominal Pain↗
PubMed2003

Risks and benefits, advantages and disadvantages of levonorgestrel-releasing contraceptive implants.

Levonorgestrel-releasing implants are long acting contraceptives, approved for 5 years of continuous use. Two marketed systems, the six capsule Norplant use of tradenames is for product identification purposes only and does not imply endorsement. and the two rod Jadelle, have essentially equal rates of drug release, pregnancy and adverse events over 5 years of use. Randomised clinical trials and controlled cohort observations indicate that for the first 3 years, when pregnancy rates are at or almost zero, no other contraceptive system is more effective, although etonogestrel implants provide equal effectiveness. Annual pregnancy rates rise in the fifth year of continuous use but remain below 1 per 100 women. Annual pregnancy rates of Norplant users remain below 1 per 100 throughout 7 years of continuous use. Levonorgestrel implants provide low progestogen doses; 40-50 microg/day at 1 year of use, decreasing to 25-30 microg/day in the fifth year. Serum levels of levonorgestrel at 5 years are 60-65% of those levels measured at 1 month of use. Adverse effects with levonorgestrel implants are similar to those observed with progestogen only and combined oral contraceptives. Risks of ectopic pregnancy, other pregnancy complications and pelvic inflammatory disease are reduced in comparison with those of women using copper or non-medicated intrauterine devices. Risks of developing gallbladder disease and hypertension or borderline hypertension, although small, are about 1.5 and 1.8 times greater, respectively, in women using levonorgestrel implants than in women not using hormonal contraception. Other serious diseases have not been found to occur significantly more frequently in levonorgestrel implant users than in women not using hormonal contraception. The great majority of levonorgestrel implant users experience menstrual problems, but serious bleeding problems are not more frequent than in controls. Other health problems reported more frequently by levonogestrel implant users than by women not using hormonal contraception in a study of 16000 women included skin conditions, headache, upper limb neuropathies, dizziness, nervousness, malaise, minor visual disturbances, respiratory conditions, arthropathies, weight change, anxiety and non-clinical depression. Clinical depression is not more frequent in women using implants compared with those not using hormonal contraception (i.e. using intrauterine devices, sterilisation). Removal problems occur less frequently with Jadelle than with Norplant. The mean removal time for Jadelle is half that of Norplant. Levonorgestrel implants in nationally representative scientific samples, in randomised trials, and in controlled cohort studies have continuation rates as high as or higher than any other reversible contraceptive over a duration of 5 years. This would imply that the satisfaction women derive from the contraceptive effectiveness of levonorgestrel implants greatly outweighs the dissatisfaction that may accompany menstrual disturbances and other adverse effects associated with implants.

Contraceptive Agents, Female↗
PubMed1998

Ovarian function during the use of a single contraceptive implant: Implanon compared with Norplant.

OBJECTIVE: To study the mechanism of action of Implanon, a single-rod contraceptive implant containing etonogestrel, in healthy women during 3 years. DESIGN: Prospective, randomized comparison with Norplant. The study was conducted for 2 years in Sweden but was extended to 3 years in Finland. SETTING: Two outpatient clinics. PATIENT(S): Thirty-two healthy women who were between 18 and 40 years of age with normal ovulatory cycles. Seven women receiving Implanon and three receiving Norplant participated in the third year. INTERVENTION(S): On or between days 1 and 5 of a spontaneous menstrual cycle, the subjects received either the etonogestrel-containing implant (Implanon) or the levonorgestrel-containing implant (Norplant). MAIN OUTCOME MEASURE(S): Ultrasonography was performed and/or progesterone concentrations were determined to confirm ovulation in a control cycle. Follicular development, endometrial thickness, and serum concentrations of 17beta-estradiol and progesterone were assessed twice per week during 4-week periods at regular intervals and after implant removal for 6 weeks to monitor return of ovulation. Times required to remove the respective implants were evaluated, as were possible complications. RESULT(S): Seven women who received Implanon and three who received Norplant completed 3 years of study. There were no pregnancies. Ovulation was observed for the first time with Norplant after 18 months. The first ovulation with Implanon was observed after 30 months. Mean endometrial thickness was <4 mm during treatment with Implanon from month 12 onward. The mean (+/-SD) time to remove Implanon was 5.9 +/- 3.4 minutes. The mean (+/-SD) time to remove Norplant was 17.9 +/- 9.9 minutes. Ovulation resumed promptly after the use of either implant. CONCLUSION(S): Results from this study provide convincing evidence of 3-year contraceptive efficacy with Implanon, mainly by ovulation inhibition.

Adult↗
PubMed1993

Release kinetics of 3-keto-desogestrel from contraceptive implants (Implanon) in dogs: comparison with in vitro data.

Ethylene-vinyl acetate (EVA) polymeric contraceptive implants (Implanon) containing 3-keto-desogestrel have been prepared aiming at an in vitro initial release rate of 60 micrograms 3-keto-desogestrel/day. These implants are designed to have an intended life-time of 2 years. During a 3-year period, the release of these implants was studied in 4 dogs after subdermal insertion, using plasma clearance of 3-keto-desogestrel assessed after intravenous administration of 3-keto-desogestrel and steady state plasma levels of 3-keto-desogestrel. The mean plasma level of 3-keto-desogestrel decreased gradually during the first year of the study, viz. from 1.64 nmol/1 at 7 days after implantation to 0.69 nmol/l after one year. At the end of the second year, the level had decreased further to 0.45 nmol/l while after 3 years, the mean 3-keto-desogestrel plasma level was 0.42 nmol/l. The calculated mean daily release of 3-keto-desogestrel decreased during the first year from 70 micrograms/day to 30 micrograms/day. During the second and third year, the decrease in release rate was much less, viz. going from 30 micrograms/day to 28 micrograms/day and from 28 micrograms/day to 25 micrograms/day, respectively. This indicates a much more constant release during the second and third year of the study. The calculated cumulative amount of 3-keto-desogestrel released from the implant during the dog study was 34.0 mg. Based on the initial amount of 3-keto-desogestrel in the implant of 68.3 mg, the remaining amount in the implants at termination of the study should be approximately 34.3 mg. Actually, the mean remaining amount of 3-keto-desogestrel was 33.8 mg, which is in very close agreement with the calculated value. Implants from the same batch as used in the in vivo study were also analyzed for the in vitro release at regular times during the 3-year study period. After one year, the in vitro release rate was about 43 micrograms/day whereas this release rate was 33 and 27 micrograms/day after 2 and 3 years, respectively. Although the in vitro set-up constantly gave a somewhat higher release in comparison with the in vivo release, it is apparent that the in vitro procedure is valuable for prediction of the in vivo release characteristics of the implant. There were no indications for 3-keto-desogestrel accumulation at the implantation site. No local irritations were seen and the animals had no discomfort at all.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1998

Pharmacokinetics of etonogestrel released from the contraceptive implant Implanon.

Eight healthy women between 22 and 40 years of age participated in this prospective open study of 2 years' duration. Either on or between days 1 to 7 of a spontaneous menses, an intravenous bolus dose of 150 micrograms etonogestrel (3-ketodesogestrel) was given. During days 1-5 of a subsequent spontaneous cycle, the single-rod contraceptive implant (Implanon) was inserted in the upper arm of the volunteer. One year after placement of the implant, another intravenous bolus dose was given (implant in place), and a third bolus dose was given after 2 years, with the implant removed. Frequent serum sampling immediately after the intravenous dosings of etonogestrel was done to study the primary pharmacokinetic parameters, i.e., volume of distribution and clearance, allowing the calculation of the absorption rate and bioavailability of the implant, as a function of time. Results showed that etonogestrel released from Implanon has an absorption rate of approximately 60 micrograms/day after 3 months, which slowly decreases to 30 micrograms/day at the end of 2 years. The bioavailability over this period of time was constant and close to 100%. The clearance remained around 7.5 L/h. With a bioavailability and clearance that remained constant, it may be concluded that there is no accumulation of etonogestrel.

Absorption↗
PubMed2004

Two-year performance of a Nestorone-releasing contraceptive implant: a three-center study of 300 women.

A 2-year trial of a single Nestorone (NES) rod implant was conducted at three Latin American centers, each enrolling 100 women. We studied the safety, effectiveness and acceptability of this progestin-releasing contraceptive implant. Three pregnancies occurred, the last at 18 months of use. Because no pregnancies were expected in the first 18 months, the trial was halted. At that time, 224 women had completed at least 18 months of use, and 99 women had used the implant for more than 24 months. Few participants used adjunctive contraception between the time the study was halted and the time they had their implant removed. No additional pregnancies occurred before the removal of the last implant. The 2-year cumulative pregnancy rate was 1.7 per 100 with a Pearl index of 0.6 per 100 for the 2-year period. The 1-year and 2-year continuation rates were 80.5 and 66.7 per 100, respectively. Menstrual and medical disturbances were the principal reasons for discontinuation, followed by planned pregnancy. Headache and weight gain frequently led to discontinuation. The NES implant had little important effect on most clinical chemistry and lipid parameters. Over the study course, the mean change in hemoglobin was <1%. Slight modification of the design of this single 2-year implant, restoring features previously examined in clinical trials, is likely to improve its effectiveness. A single NES implant appears to provide acceptable contraception for women.

Adolescent↗
PubMed1985

Facts about an implantable contraceptive: memorandum from a WHO meeting.

This Memorandum reviews the results of research undertaken in animals and human subjects on the implantable contraceptive, Norplant, and where relevant, its components, levonorgestrel and Silastic. Results from clinical trials, including effectiveness and side-effects, are evaluated and service delivery aspects commented on. The Memorandum concludes with a statement regarding the use of Norplant as an option for long-term reversible contraception.

Animals↗
PubMed2005

[Ectopic pregnancy with etonogestrel contraceptive implant (Implanon): first case].

We describe the first case of ectopic pregnancy occurring in a patient with an etonogestrel contraceptive implant (Implanon). There was no factor predisposing to a failure of the technique (implant in place for less than 2 years and normal BMI). In addition there was no risk factor for an ectopic location of the pregnancy. We discuss the role of the micro progestative in the location of the pregnancy. This case report emphasizes the fact that ectopic pregnancy should not be ruled out in women taking this contraception, however efficient it is otherwise.

Contraceptive Agents, Female↗
PubMed1995

Ultrasonography: usefulness in localization of the Norplant contraceptive implant system.

Norplant is a levonorgestrel-containing contraceptive system that consists of six small capsules (2.4 x 34 mm), which are placed subdermally. Owing to the relative newness of this contraceptive modality, problems with removal of the Norplant implants are just beginning to be reported; these consist primarily of inability to locate and remove all six implant capsules upon discontinuation. Ultrasonographic images of 14 women with the Norplant system in place were obtained in the axial and longitudinal planes. On axial view the capsules consisted of discrete circular individual areas of high echogenicity with prominent posterior shadowing. Capsules scanned in a longitudinal plane demonstrated echogenicity of the superior and inferior capsular walls, giving a tubular appearance. It was possible to demonstrate the depth of capsule placement, spatial relation to surrounding capsules, and orientation in relation to the skin surface. Ultrasonography therefore may provide a useful, noninvasive method for localization of nonpalpable Norplant implants, thus facilitating removal.

Arm↗
PubMed2001

Post-marketing surveillance of Norplant((R)) contraceptive implants: II. Non-reproductive health(1).

This controlled cohort study aimed to evaluate the safety and efficacy of Norplant contraceptive implants in developing countries. Women initiating Norplant implants were index subjects and women initiating intrauterine devices (IUDs) or surgical sterilization were controls. Consenting participants at 32 clinics in eight developing countries were admitted and followed-up every 6 months for 5 years. Major and less serious health events during follow-up were recorded. Incidence rate ratios of health events adjusted for clinic were estimated for initial and current method use. This paper reports non-reproductive health events. The study involved 7,977 women initiating use of Norplant, 6,625 of IUD, and 1,419 of sterilization. Five years follow-up was completed for 94.6% of the women. The study accumulated 78,323 woman-years of observation. The initial method chosen accounted for 84.4% or more of observed woman-years in users of Norplant, IUD, or sterilization. Twenty-two of the recorded 34 deaths were due to accidents, suicide or homicide. Few deaths or major health events were due to cancer or acute cardiovascular diseases and were not associated with the contraceptive method used. The incidence rates of major health events were low and with two exceptions, there was no significant excess risk of serious morbidity for Norplant users compared with controls; among Norplant initiators gallbladder disease occurred at an incidence rate of 1.5 per 1,000 woman-years and was weakly associated with use of Norplant (rate ratio 1.52 [95% C.I. 1.02, 2.27]). For current Norplant users compared to controls, the rate ratio of a combined variable of hypertension and borderline hypertension was significantly elevated (1.81, [1.12, 2.92]). The occurrence of less serious health events was also low and several of them were significantly more often reported among Norplant users. Headache-migraine, weight gain, mood disturbances, pruritus, eczema, and acne had incidence rates among Norplant users of 11.5, 4.5, 2.8, 1.5, 1.4, and 0.9 per 1,000 woman-years, respectively, and were significantly higher than in controls. Respiratory health problems, nonspecific symptoms, and several ill-defined conditions were also significantly more often reported for Norplant users, but some of the excess incidence may be attributable to reporting and detection bias. The study confirms the safety with respect to serious disease of Norplant, IUDs, and sterilization.

Accidents↗
PubMed1999

A multicentre efficacy and safety study of the single contraceptive implant Implanon. Implanon Study Group.

An open, multicentre study was performed to assess efficacy, safety and acceptability of the single-rod contraceptive implant Implanon. The study involved 635 young healthy women, who were sexually active and of childbearing potential. The women were followed up every 3 months over the entire study period. Originally the study was designed for 2 years, but was extended to 3 years in a group of 147 women from two centres. Altogether, 21 centres in nine different countries participated. The average age of the women was 29 years (range 18-42 years), of whom 83.5% had been pregnant in the past. No pregnancy occurred during treatment with Implanon, resulting in a Pearl Index of 0 (95% confidence interval: 0.0-0.2). In the first 2 years, 31% had discontinued the treatment. Of the 147 women in the study extension, nine discontinued (6%) treatment. Bleeding irregularities was the main reason for discontinuation during the first 2 years of use (17.2%) and adverse experiences in the third year (3.4%). Implant insertion and removal were fast and uncomplicated in the vast majority (97%) of cases. Return of fertility was prompt. In conclusion, Implanon has excellent contraceptive action during its lifetime of 3 years. The safety profile is acceptable and not essentially different from progestogens in general.

Adolescent↗
PubMedDate not supplied

Vaginal bleeding patterns in Nigerian users of nomegestrol acetate subdermal contraceptive implant.

A 12 months longitudinal study was carried out in 214 consecutive Nigerian women using Nomegestrol acetate subdermal contraceptive implant (Uniplant) for the first time to establish the rates of different vaginal bleeding patterns according to WHO bleeding/spotting classification, and to assess their relationship with Uniplant discontinuation. The results showed an initial rise in the number of women experiencing altered vaginal bleeding which continued to fall towards the 12th month of use (57.01% vs 26.17%). Similarly, a significant increase in mean menstrual cycle length occurred in the first trimester of use and this disappeared by the third trimester. The mean numbers of bleeding/spotting days and bleeding/spotting free intervals increased significantly from first trimester to the fourth trimester. No change was noted in the mean number of bleeding/spotting episodes through, out the follow up period. The total discontinuation rate was 15.42%. Discontinuation on account of altered vaginal bleeding pattern was 3.27%. One accidental pregnancy occurred during follow up (Pearl index = 0.52). No significant change in haemoglobin levels was noted in the women. It was concluded that changes in menstrual patterns in Uniplant users occur mostly in the first six months of use and are unlikely to have any deleterious effects on the general health of the users.

Adult↗
PubMed1984

Effect of subdermal levonorgestrel contraceptive implants, Norplant, on liver functions.

Forty-seven normal health women were studied longitudinally for changes in liver functions during the use of the levonorgestrel contraceptive implant system, NORPLANT. Samples were collected before insertion of the implants and after one, three and six months of use. The enzymes studied were the transaminases (SGOT and SGPT), alkaline phosphatase and gamma-glutamyl transferase. Serum bilirubin and bile acid levels were also measured. The protein synthetic function of the liver was tested by estimation of total proteins, albumin, transferrin, hemopexin, ceruloplasmin and haptoglobin. The three main immunoglobulins, G, M and A, were also measured. There were no significant changes in the liver enzymes after NORPLANT use. Serum bilirubin and bile acid concentrations showed rises in the first month of use which ameliorated in subsequent months. Serum albumin was transiently increased during the first and third months. Ceruloplasmin decreased significantly at the sixth month. The concentrations of total serum proteins and the other individual proteins showed no significant change. The results point to safety of NORPLANT implant use, as regards hepatic functions.

Adult↗
PubMed2003

Enlarged ovarian follicles in users of a levonorgestrel-releasing intrauterine system and contraceptive implant.

OBJECTIVE: To evaluate the prevalence of enlarged ovarian follicles among users of a 20 micrograms/d levonorgestrel-releasing intrauterine system (Mirena, Leiras Oy, Turku, Finland), of subdermal contraceptive implants releasing Nestorone (Population Council, New York, New York) and of the TCu 380A intrauterine device. STUDY DESIGN: A cohort study was conducted at the Universidade Estadual de Campinas, Brazil. Three hundred women were enrolled, with 100 participants in each group. Bimanual pelvic examination and vaginal ultrasound were performed during routine gynecologic examinations in women without complaints. In women with enlarged ovarian follicles (> or = 25 mm), estradiol and progesterone levels were assessed weekly until disappearance or reduction of the ovarian image. RESULTS: Enlarged ovarian follicles were detected in 19%, 10% and 5% of users of the levonorgestrel system, implants and intrauterine device, respectively. Most of the enlarged ovarian images disappeared after 2 weeks of follow-up. Progesterone levels showed that the intrauterine system and TCu 380A IUD (FEI, North Tonawanda, New York) users had presumably ovulated before the first ultrasound examination in contrast to the implant users. CONCLUSION: Physicians and users should be aware that findings of enlarged ovarian follicles during the use of progestin-only contraceptives are transient and that no medical interventions are necessary.

Adult↗