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PubMed1979

The effect of cyclical administration of levonorgestrel and ethinyloestradiol on blood pressure, body mass, blood glucose and serum triglycerides.

The effects of two differing dosage schedules of ethinyloestradiol and levonorgestrel, taken cyclically as oral contraceptives, on blood pressure, body mass, blood glucose and serum triglycerides were measured. After 12 months there were no significant changes in systolic and diastolic blood pressure or blood glucose levels. There was a small but statistically significant increase in body mass after 1 year in the group taking levonorgestrel 15 microgram and ethinyloestradiol 30 microgram (P < 0,02), but not in the other group, although the mass in this group was significantly increased after 3 months of therapy. There was a statistically significant increase in serum triglycerides in the group taking levonorgestrel 50 microgram with ethinyloestradiol 50 microgram for 11 days, followed by levonorgestrel 125 microgram for 11 days, followed by levonorgestrel 125 microgram with ethinyloestradiol 50 microgram for 10 days. This effect appears to be dose-related and progressive with continued therapy; the significance of these results is discussed.

Adolescent↗
PubMed2003

Levonorgestrel as an emergency contraceptive drug.

The potential of low-dose levonorgestrel, alone or in combination with ethynyloestradiol (Yuzpe regimen), as emergency contraception is reviewed for its acceptability and effectiveness. Plasma levonorgestrel concentration ranges from 9-12 nmol/l at 12 hours with a peak of 27-33 nmol/l 2-2.5 hours after taking one 0.75 mg tablet. The concentration of steroid hormone binding globulins in plasma is not influenced by the presence of levonorgestrel during this period. The success rates for levonorgestrel-only and the Yuzpe regimen as emergency contraception are 85% and 57%, respectively, while the failure rates are 1.1% and 3.2%, respectively, within the prescribed time limit of use. The mode of action of levonorgestrel emergency contraception is to prevent or delay ovulation and/or alter the endometrium unfavourably the for implantation of an embryo. The use of emergency contraceptive pills within 72 hours after unprotected sexual intercourse reduces the risk of pregnancy by about 75% and is safe, with no serious side-effects.

Adolescent↗
PubMed2004

Bioequivalence study of postcoital emergency contraceptions containing levonorgestrel.

OBJECTIVE: The progestogen-only method of emergency contraception, levonorgestrel, is one of the effectiveness in preventing expected pregnancies. The comparative bioavailability was carried out on levonorgestrel tablets (0.75 mg) from two different sources (Hungarian and Thai made). METHOD: Eighteen healthy female volunteers were given a single oral dose of 0.75 mg tablets in a crossover design. Serum levonorgestrel concentration was determined by radio-immunoassay. The pharmacokinetic analysis of serum levonorgestrel concentration from each treatment was established. The comparative bioavailability of the two products was determined by the analysis of variance (ANOVA) for two way crossover design. RESULTS: The results found that the mean peak (X +/- SD) serum concentration (Cmax) of the Thai-made pill and Hungarian-pill were 1.18 +/- 0.12 and 1.14 +/- 0.10 ng/ml, respectively. The 90% confidence intervalfor the difference of log Cmax mean was 99.54-120.78%. The time to peak serum concentration (Tmax) of the Thai-made pill and Hungarian-pill were 1.56 +/- 0.73 and 1.58 +/- 0.67 hrs, respectively. The different time of peak serum levonorgestrel concentration was 1.27%. The mean area under the curve (AUC) of Thai-made pill and Hungarian-pill were 2.14 +/- 0.21 and 2.09 +/- 0.16 ng.h/ml, respectively. The 90% confidence interval for the difference of log AUC mean was 103.27 - 121.89%. CONCLUSION: The present study revealed that the 90% confidence interval for the difference of log Cmax mean and log AUC mean were in the criteria of acceptance, which should be within 80-125%. So, the authors can conclude that the Thai-made pill was bioequivalent to the Hungarian-pill.

Adult↗
PubMed1991

Prostaglandin production in human endometrium following continuous exposure to low-dose levonorgestrel released from a vaginal ring.

Arachidonic acid metabolites produced by primary cultures of human endometrial cells derived from biopsies obtained before and after exposure to 20 micrograms/day levonorgestrel for 84 +/- 1 days were analysed by reverse phase HPLC. This revealed a significant increase in PGF1 alpha and an epoxide metabolite upon levonorgestrel stimulation. The proportion of epoxide metabolite, PGF1 alpha and PGE2 were positively correlated with serum levonorgestrel levels while HETES, PGE2 and epoxide were similarly correlated with serum oestradiol. The extent of intermenstrual bleeding during exposure to levonorgestrel was correlated with the proportion of epoxide and HETES products in vitro which is discussed in relation to their physiological function.

6-Ketoprostaglandin F1 alpha↗
PubMed1980

Plasma levels of levonorgestrel in women during longterm use of Norplants.

Levonorgestrel plasma levels were determined by a specific radioimmunoassay in a group of 110 women at various intervals between 1 and 60 months following implantation of six silastic capsules containing levonorgestrel (Norplant). The implants were placed subdermally in the anterior aspect of the forearm. Blood samples were taken twice a week for six consecutive weeks in each subject. Blood drawn from the antecubital vein ipsilateral to the implant site contained two to three times more levonorgestrel than contralateral samples. Average systemic plasma levels represented by contralateral samples ranged from 0.35 +/- 0.03 to 0.29 +/- 0.02 ng/ml (Mean +/- S.E.) in the first and fifth year, respectively. The difference between these values is statistically significant at the 6% level. The results of the regression analysis of individual levels suggest that the decline observed throughout the first five years is mainly due to an early decrease taking place in the first two years. When the sampling period was repeated in the same subjects two or three times 10 to 24 months apart, no significant difference was found. A significant negative correlation was found between plasma levonorgestrel levels and body weight and body surface. The data indicate that the contraceptive efficacy of Norplants during the first five years of use is associated with sustained release of levonorgestrel and is in keeping with the estimated life span of Norplants of seven years.

Adult↗
PubMed1990

Pharmacokinetic and pharmacodynamic studies of levonorgestrel-releasing intrauterine device.

Intrauterine devices releasing 20 micrograms/day levonorgestrel were inserted in 10 women (ages 25-34). Bleeding and spotting patterns were recorded on a menstrual card during one year of follow-up. Blood samples were collected for radioimmunoassays of LH, estradiol (E2), progesterone (P) and levonorgestrel (LNG) and for sex hormone binding globulin (SHBG) 3 times a week during the 1st month of use, and twice a week during the 6th and 12th treatment months. Among the 10 women, two experienced irregular cycles with prolonged intermenstrual spotting, four had amenorrhea in the latter part of treatment months, while the other four had regular cycles. According to the serum levels of E2 and P, the hormone profiles were divided into four types of reaction: A) anovulatory, B) anovulatory but with high follicular activity, C) ovulatory but with luteal insufficiency, and D) ovulatory. Among the 29 treatment cycles, there were 10 D-type, 3 C-type, 13 B-type and 3 A-type of ovarian reactions: 44.8% of the cycles were ovulatory (C + D) and 55.2% were anovulatory (A + B). In general, serum levels of levonorgestrel were low in ovulatory cycles and were high in anovulatory cycles. The difference was statistically significant. There were marked individual differences. The decline of serum LNG from the 1st (492 pmol/l) to the 6th (320 pmol/l) treatment months was 34.9% on average. The amenorrheic cycles coincided mostly with the hormonal profile of ovulatory types, which indicated that the cause of amenorrhea is due to the local effect of levonorgestrel on the endometrium. The levonorgestrel levels were significantly correlated with serum SHBG, r = 0.8856, p less than 0.001, and with E2, r = 0.4661, p less than 0.05.

Adult↗
PubMed1979

Plasma lipids and high density lipoproteins during oral contraception with different combinations of ethinyl estradiol and levonorgestrel.

Seventy-five menstruating women seeking contraceptive advice were randomly allocated to treatment with combined oral contraceptives containing either ethinyl estradiol 50 micrograms + levonorgestrel 250 micrograms (50/250), ethinyl estradiol 30 micrograms + levonorgestrel 150 micrograms (30/150) or ethinyl estradiol 50 micrograms + levonorgestrel 125 micrograms (50/125). The concentrations of cholesterol, triglycerides, phospholipids, high density lipoprotein (HDL)-cholesterol and HDL-phospholipids were determined after one, three and six months and compared to the mean of two determinations of the same parameters before medication. Triglycerides increased by 18--42 per cent after 1--6 months of treatment with 50/125. The HDL-cholesterol and HDL-phospholipids were reduced by 10 per cent during 50/250 treatment. No other parameters showed any consistent alteration in any of the treatment groups. Raised triglyceride concentration and/or decreased HDL concentration increases the risk for cardiovascular disease. It is therefore suggested that in order not to alter the HDL concentration a combined oral contraceptive agent should not contain more gestagen-androgen than corresponding to 125--150 micrograms of levonorgestrel. To avoid a rise of the triglyceride level the weight relation between levonorgestrel and ethinyl estradiol should be about 5:1.

Adult↗
PubMed1979

Effects of three different combinations of ethinyl estradiol and levonorgestrel on plasma lipids and high density lipoproteins.

Seventy-five menstruating women seeking contraceptive advice were randomly allocated to treatment with combined oral contraceptives containing either ethinyl estradiol 30 micrograms + levonorgestrel 150 micrograms (30/150), ethinyl estradiol 50 micrograms + levonorgestrel 125 micrograms (50/125) or ethinyl estradiol 50 micrograms + levonorgestrel 250 micrograms (50/250). The concentrations of cholesterol, phospholipids, high density lipoprotein (HDL)-cholesterol, HDL-phospholipids and triglycerides were determined prior to treatment and after one, three and six months of medication. Triglycerides increased by 18--42 per cent after one to six months of treatment with 50/125. The HDL-cholesterol and HDL-phospholipids were reduced by 10 per cent during 50/250 medication. No other parameters showed any consistent alteration in any of the treatment groups. Raised triglyceride concentration and/or decreased HDL concentration may increase the risk for cardiovascular disease. It is therefore suggested that in order not to alter the HDL concentration a combined oral contraceptive agent should probably not contain more 19-nortestosterone type of progestogen than corresponding to 125--150 micrograms of levonorgestrel. To avoid a rise of the triglyceride level the weight relation between levonorgestrel and ethinyl estradiol should be about 5:1.

Cholesterol↗
PubMed1979

First year clinical experience with six levonorgestrel rods as subdermal contraception.

Previous clinical experience with six levonorgestrel subdermal capsules showed a very good contraceptive effectiveness and continuation rate, but with a high proportion of bleeding disturbances, particularly of increased bleeding. It was hypothesized that bleeding could be reduced by higher plasma levels of the steroid, using subdermal rods instead of capsules, as rods have been shown to have a release rate 3 or 4 times that of the capsules. Fifty volunteers were enrolled in a study of the clinical performance of 6 subdermal levonorgestrel rods. Results were compared with a previous experience with 100 volunteers who wore 6 levonorgestrel capsules for a year in the same clinic. Requirement for volunteers to enter the study were the same for capsules and rods. The proportion of women wearing 6 subdermal rods who had increased bleeding was about one half as for the women using 6 levonorgestrel capsules. On the other hand, women using rods had about twice the incidence of amenhorrea, and about four times more hypomenorrhea (4 days or less of bleeding in a 90-day period). There were no pregnancies among the rod users and the discontinuation rate for medical reasons was not higher than for capsule users in the same clinic.

Adolescent↗
PubMed1991

Endometrial vascular features prior to and following exposure to levonorgestrel.

A study of endometrial vasculature, mast cell numbers and tissue levels of tissue plasminogen activator (tPA) prior to and following exposure to levonorgestrel (20 micrograms/day) administered via a vaginal ring was undertaken. Following exposure to levonorgestrel, significantly fewer arterioles were present in the endometrium. During the early secretory phase of the control cycle, a positive correlation was found between mast cell numbers and progesterone levels. Levonorgestrel-exposed biopsies had significantly higher numbers of vessels with endothelial gaps and haemostatic plugs when compared with early secretory endometrium and significantly higher numbers of haemostatic plugs when compared with mid-late secretory endometrium. During the early secretory phase, the numbers of vessels possessing haemostatic plugs positively correlated with the peripheral blood levels of oestradiol and the number of contracted endothelial cells showed a positive correlation with progesterone levels. In mid-late secretory biopsies, the numbers of vessels with contracted endothelial cells were found to correlate negatively with oestradiol levels and the difference in the levels of contracted endothelial cells between the mid-late secretory endometrium and levonorgestrel-exposed endometrium correlated positively with progesterone levels of post-treatment cycles.

Arterioles↗
PubMed1991

Lysosomal enzymes in the human endometrium: a biochemical study in untreated and levonorgestrel-treated women.

The activities of four lysosomal enzymes, i.e. N-acetyl-beta-hexosaminidase, acid phosphatase, alpha-D-mannosidase and alpha-L-fucosidase have been measured in extracts of endometrial biopsies from untreated and levonorgestrel-treated women of fertile age. Values were compared with protein and DNA content, as well as with lactate dehydrogenase activity, used as reference constituents. In parallel, organ cultures were established from the same endometrial specimens and the release of lysosomal enzymes into the medium was followed. The human endometrium possesses a rich lysosomal equipment, comparable to that found in the human liver. In the untreated cycles, the activities of lysosomal enzymes show a coordinate response to the hormonal changes, decreasing by about 40% from the proliferative to the mid-late secretory phase. Long-term levonorgestrel treatment causes a marked cytoplasmic atrophy, as shown by decreased protein content and lactate dehydrogenase activity, whereas DNA content remains unchanged. In contrast, N-acetyl-beta-hexosaminidase, one of the most active lysosomal enzymes studied, shows a higher specific activity upon levonorgestrel. In both untreated and treated endometria, the organ cultures provide biochemical evidence for a higher release of N-acetyl-beta-hexosaminidase than of lactate dehydrogenase, indicating active secretion of the lysosomal enzyme. During levonorgestrel treatment, there was no correlation between clinically recognized spotting-bleeding patterns and lysosomal enzyme content in, or release from, the endometrium.

Acetylglucosaminidase↗
PubMed1996

Serum concentrations of estradiol, progesterone, and levonorgestrel are not determinants of endometrial histology or abnormal bleeding in long-term Norplant implant users.

The objective of this study was to determine the relevance of serum estradiol, progesterone and levonorgestrel concentrations to endometrial histology and uterine bleeding associated with long-term Norplant implants use. Eighteen five-year users of Norplant implants had endometrial biopsies and determinations of serum estradiol, progesterone and levonorgestrel concentrations. Correlations among these factors and uterine bleeding were calculated. Proliferative endometrium (but not sex steroid levels) was associated with abnormal bleeding. Neither ovarian steroid nor levonorgestrel concentrations was a predictor of abnormal bleeding. Hyperplastic changes were not seen even with high estradiol and low levonorgestrel levels.

Adult↗
PubMed1985

Long-acting injectable microsphere formulation for the parenteral administration of levonorgestrel.

The pharmacokinetic and pharmacodynamic effects of a long-acting formulation of levonorgestrel microencapsulated in a biodegradable polymer poly(DL-lactide-CO-glycolide) was tested in baboons. The polymer microspheres provided continuous release of levonorgestrel for up to 6 months following a single intramuscular injection. The treatment inhibits ovarian function for 3-6 months, depending on the dose. The duration and pattern of levonorgestrel release varies according to the quality and size of the microspheres. The microsphere delivery system offers a promising new approach to developing a long-acting injectable contraceptive based on levonorgestrel.

Animals↗
PubMed1993

Levonorgestrel levels in serum and uterine flushings in women bearing LNG-Cu-IUD.

Radioimmunoassay was employed to measure levonorgestrel levels in serum and uterine flushings in women using intrauterine device releasing both copper ions and levonorgestrel (LNG-Cu-IUD) after one-year insertion. In the meanwhile physical characteristics of cervical mucus have been observed in women using LNG-Cu-IUD and compared with those using Tcu-220c-IUD. The mean concentrations of levonorgestrel in serum and uterine flushings (5 ml) were 84.53 pg/ml and 266.93 pg/ml respectively. In LNG-Cu-IUD group, the cervical mucus lacking in ferny crystals had a viscosity significantly higher than that in Tcu-220c-IUD group, suggesting that the local high concentration of levonorgestrel changed the environment of the uterine cavity and the cervical mucus status.

Adult↗
PubMed1995

Transdermal estrogen with a levonorgestrel-releasing intrauterine device for climacteric complaints: clinical and endometrial responses.

OBJECTIVE: Our purpose was to study the effects of intrauterine release of a daily dose of 20 micrograms levonorgestrel by an intrauterine device on climacteric symptoms, bleeding pattern, and endometrial histologic features in postmenopausal women receiving transdermal estrogen replacement therapy. STUDY DESIGN: Forty parous postmenopausal women were randomly allocated into two groups for 1 year: 20 women receiving a continuous transdermal daily dose of 50 micrograms of estradiol had a levonorgestrel-releasing intrauterine contraceptive device inserted, and the control group of 20 women received a continuous oral dose of 2 mg of estradiol valerate and 1 mg of norethisterone acetate daily. The climacteric symptoms, bleeding patterns, endometrial thickness, and endometrial changes in biopsy samples were analyzed. Serum levels of estradiol in both groups and levonorgestrel levels in the intrauterine device group were also determined. RESULTS: Both treatment regimens effectively relieved climacteric symptoms. Spotting was more common in the intrauterine contraceptive device group than in the oral therapy group for the first 3 months. After that, the proportion of women without any bleeding was similar in both groups. Two patients in each group dropped out because of bleeding. CONCLUSION: These preliminary findings suggest that the levonorgestrel-releasing intrauterine contraceptive device is a useful alternative mode of progestin administration for certain selected women receiving estrogen replacement therapy.

Administration, Cutaneous↗
PubMed1987

Effects of levonorgestrel on enzymes responsible for synthesis of triacylglycerols in rat liver.

The effects of levonorgestrel treatment (4 micrograms/day per kg body weight 0.75 for 18 days) on rate-limiting enzymes of hepatic triacylglycerol synthesis, namely glycerol-3-phosphate acyltransferase and phosphatidic acid phosphatase were investigated in microsomal, mitochondrial and cytosolic fractions of rat liver. Levonorgestrel treatment resulted in a significant reduction (26%) of hepatic microsomal glycerol-3-phosphate acyltransferase specific activity. Hepatic mitochondrial glycerol-3-phosphate acyltransferase specific activity was unchanged. Levonorgestrel treatment also significantly reduced (by 20%) the specific activity of hepatic microsomal magnesium-independent phosphatidic acid phosphatase. However, magnesium-dependent phosphatic acid phosphatase specific activities in microsomal and cytosolic fractions were unaffected. Cytosolic magnesium-independent phosphatidic acid phosphatase activity was also unchanged. These studies are consistent with the view that levonorgestrel lowers serum triacylglycerol levels, at least in part, by inhibition of the glycerol-3-phosphate acyltransferase (EC 2.3.1.15) step in hepatic triacylglycerol synthesis.

Animals↗
PubMed1982

Duration of breast-feeding and development of children after insertion of a levonorgestrel-releasing intrauterine contraceptive device.

IUDs releasing levonorgestrel, 10 micrograms per day (30 patients) and 30 micrograms per day (40 patients), and copper-releasing IUDs (Nova-T) (40 patients) were inserted six weeks after delivery in 110 breast-feeding amenorrheic women. The infants were carefully followed-up by recording monthly weight gain and growth, age of eruption of the first tooth, age of being able to walk without support and morbidity to infective diseases. No differences were noticed between the study groups. Plasma samples were collected from 13 children at the age of eight months, while the mothers were breast-feeding. Six mothers had a levonorgestrel-releasing IUD and seven others the Nova-T or no hormonal or intrauterine contraceptive. No differences were noticed between the groups in Na, K, Cl, Ca, P, protein, albumin, creatinine, urate, Fe, cholesterol, triglyceride, bilirubin, alkaline phosphatase, aspargine aminotransferase, alanine aminotransferase, lactate-dehydrogenase or high density lipoprotein cholesterol serum concentrations in the children. The duration of breast-feeding and initiation of supplementary feeding was recorded. The continuation of breast-feeding 75 days after the insertion of a 30-micrograms per day levonorgestrel-releasing IUD was 56 percent while in the Nova-T group only 21 percent had discontinued which is a statistically significant difference (p less than 0.05); later the difference disappeared. Compared with the lactation time of their previous breast-feeding reported by women in both groups, the present lactation time increased by ten weeks. The infants received substitute foods including substitute milk, juices, etc., in the Nova-T group at 3.9 months and in the levonorgestrel-releasing IUD group at 3.4 months after delivery.

Adolescent↗
PubMed1982

Long-term intracervical contraception with a levonorgestrel device.

An intracervical levonorgestrel-releasing mini-T device was tried as contraceptive in 100 fertile multiparous women for 3 years. This device release about 10 micrograms/day. The results were compared with those of an intrauterine levonorgestrel device and copper-T-200 (Cu-T-200). The continuation rates of the three device did not reveal any significant differences at 1, 2 and 3 years. Incidence of unintended pregnancies and removals due to bleeding and pain was comparable to those of Cu-T-200 but higher than those of intrauterine levonorgestrel device. The number of days of bleeding and spotting for both levonorgestrel devices was significantly lower than those for Cu-T-200.

Adult↗