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At least 19 recordsLinked to original sources
PubMed1987

Plasma levels of levonorgestrel and free levonorgestrel index in women using NORPLANT implants or two covered rods (NORPLANT-2).

Plasma levels of levonorgestrel, sex hormone binding globulin (SHBG) and estradiol were studied during four years in 283 healthy women using either NORPLANT implants or two covered rods (NORPLANT-2). The women were randomized to use either type of implant. Both implant systems have previously been shown to have similar release rates of levonorgestrel. In both groups plasma levels of levonorgestrel decreased throughout the study, and there were no statistically significant differences between the two groups in mean plasma levels of levonorgestrel. During the study 8 women became pregnant. All pregnancies but one occurred after 35 months of implant use and only in women using the covered rods. No significant differences were seen between the women who became pregnant and the rest of the group using two covered rods with respect to plasma levels of levonorgestrel. SHBG capacity tended to be somewhat higher in women using the two covered rods. As levonorgestrel is to a great extent bound to SHBG, and in that form not biologically active, a "free levonorgestrel index" was calculated as a ratio between levonorgestrel and SHBG. This index was significantly lower in users of two covered rods than in users of NORPLANT implants at 1, 12 and 48 months of use. Women who became pregnant had significantly lower "free levonorgestrel index" than had the rest of the group. It is postulated that the difference in "free levonorgestrel index" between users of the two implant systems reflect differences in release rate, the covered rods having a lower release rate of levonorgestrel than NORPLANT throughout the observation period. It is concluded that "free levonorgestrel index" is a better parameter than levonorgestrel plasma levels to describe implant function, and to discriminate women who are at risk of pregnancy.

Adult↗
PubMed1985

Plasma levonorgestrel and progesterone levels in women treated with silastic covered rods containing levonorgestrel.

Levonorgestrel and progesterone plasma levels were measured in women bearing levonorgestrel subdermal implants. Two groups using four or six levonorgestrel covered rods and one group of non-hormonal contraceptors were compared. Blood samples were drawn twice a week for six consecutive weeks at different intervals after treatment administration. The mean levonorgestrel levels (mean +/- S.D.) observed in the four rods group was .49 +/- .13 ng/ml in the first year and decreased to .34 +/- .06 in the fifth year of treatment. The mean values observed in the six rods group were .70 +/- .15 ng/ml in the second year and .43 +/- .11 in the sixth year. The levonorgestrel plasma levels were slightly above those found with Norplantr implants in the four rods group and well above it in the six rod group. The highest plasma progesterone value found in each sampling period was above 9 nmol/l in 7 (14%) out of 50 subjects in the four rods group, in 2 (4.3%) out of 47 subjects in the six rods group and in all the 49 control women. In 4 out of the 7 subjects from the 4 rods group and in the two subjects from the 6 rods group, the highest progesterone value was preceded and followed by values lower than 6 nmol/l. It was concluded that the progesterone levels were seldom compatible with the occurrence of ovulation in women treated with four or six levonorgestrel covered rods which release an estimated daily dose of 70 and 105 micrograms, respectively.

Adolescent↗
PubMed1991

Protective effect of intrauterine release of levonorgestrel on pelvic infection: three years' comparative experience of levonorgestrel- and copper-releasing intrauterine devices.

A randomized, multicenter comparison of two intrauterine contraceptive devices (IUDs) was carried out. Nine hundred thirty-seven women were fitted with a copper-releasing IUD, the Nova-T, and 1821 women with an IUD that releases 20 micrograms of levonorgestrel daily. After 36 months, the cumulative gross rates of amenorrhea and hormonal side effects were significantly higher in the levonorgestrel-IUD users. The cumulative 36-month gross pregnancy rate was 3.7 for the Nova-T and 0.3 for the levonorgestrel IUD (P less than .001), demonstrating the levonorgestrel IUD's high contraceptive efficacy. For the first time, a protective effect of the levonorgestrel IUD against pelvic inflammatory disease as compared with the Nova-T was seen statistically. The cumulative 36-month gross rate of pelvic inflammatory disease was 2.0 in Nova-T- and 0.5 in levonorgestrel-IUD users (P less than .013). This significantly lowered incidence of pelvic inflammatory disease may help to solve one of the major concerns associated with intrauterine contraception.

Adult↗
PubMed1989

Plasma levonorgestrel levels and ovarian function during the use of a levonorgestrel-releasing intracervical contraceptive device.

Levonorgestrel, estradiol and progesterone plasma concentrations were measured over four years of use of a 20 micrograms/day levonorgestrel-releasing intracervical device (LNG-ICD). The mean levonorgestrel concentration showed a slight decline, being 142 + 46 (SD) pg/ml in the third month and 81 +/- 22 pg/ml in the 48th month of LNG-ICD use. However, considerable interindividual variation in levonorgestrel plasma levels between study subjects was observed. In 77% of the monitored cycles, ovulation or a luteinized follicle was observed when judged by a plasma progesterone elevation of over 5 ng/ml. Some follicular function was also noted in anovulatory cycles. Inhibition of ovulatory ovarian function is not the mode of contraceptive action of the LNG-ICD.

Adult↗
PubMed1986

Levonorgestrel concentrations in maternal and infant serum during use of subdermal levonorgestrel contraceptive implants, Norplant, by nursing mothers.

The transfer of levonorgestrel to infants was studied in 42 lactating women in whom the contraceptive subdermal implants, Norplant, were inserted 30 to 40 days postpartum. The women breastfed their infants for one year. Simultaneous mother and infant blood samples were taken once during the year. The levonorgestrel serum concentrations were measured by radioimmunoassay. During the first postinsertion month, the levonorgestrel concentration in the infants serum amounted, on the average, to 5% of the maternal concentration. Thereafter, the ratio ranged from 8 to 13%. The implications of this finding are discussed.

Breast Feeding↗
PubMed1987

Two years of intrauterine contraception with levonorgestrel and with copper: a randomized comparison of the TCu 380Ag and levonorgestrel 20 mcg/day devices.

IUDs releasing 20 mcg/day of levonorgestrel (LNg20) were in randomized trial together with the Copper T, model TCu 380Ag, in seven centers involving 2244 women. Two-year (25 months) gross cumulative pregnancy rates were 0.2 +/- 0.2 and 0.9 +/- 0.3 for the levonorgestrel and copper releasing devices, respectively (P greater than 0.05). There were no ectopic pregnancies in more than 1600 woman-years of use of each device. Removal rates for bleeding and/or pain or for medical reasons other than menstrual problems did not differ significantly between devices. Oligomenorrhea or amenorrhea prompted 10.7 per hundred (gross rate, 8.4 net rate) women using the LNg 20 IUD to request removal in the two-year period, significantly above the 0.2 per hundred rate among women with the Copper IUD (P less than 0.001). At the end of two years an estimated 59.4 per 100 women were continuing use of the LNg 20 IUD, and 67.5 per 100 (P less than 0.001) with the TCu 380Ag. This difference is almost wholly ascribable to a marked reduction in bleeding episodes and days among women using the LNg 20 device with concomitant removal of device. Hemoglobin rose an average of 0.5 g/dl (P less than 0.001) for this group whereas women using the TCu 380Ag experienced a decline of 0.2 g/dl compared with baseline values (P less than 0.001).

Adolescent↗
PubMed1992

Pharmacokinetics of levonorgestrel in 12 women who received a single oral dose of 0.15 mg levonorgestrel and, after a washout phase, the same dose during one treatment cycle.

The pharmacokinetics of levonorgestrel (LNG) was determined in 12 healthy women (age 21 to 33 years), following single dose administration of 0.15 mg LNG. The same preparation was also administered during one treatment cycle after a washout phase of 1 week. After single dose administration, maximum concentrations of LNG in the serum were 4.3 +/- 1.3 ng/ml. Post maximum drug levels declined biphasically with half-lives of 0.6 +/- 0.2 h and 13.9 +/- 3.2 h, respectively. The clearance was calculated to be 1.5 +/- 0.6 ml x min-1 x kg-1. The free fraction of LNG was 1.1 +/- 0.1% and the fractions bound to SHBG and albumin were 61.8 +/- 6.7% and 37.1 +/- 6.7%, respectively. There was a gradual decrease in serum trough levels of LNG from about 0.5 to 0.3 ng/ml during the cycle, and a concomitant decrease in SHBG concentrations in the serum by about 50%. Serum protein binding of LNG changed markedly during the treatment cycle. The free fraction increased to a value of 1.7 +/- 0.3%, the SHBG-bound fraction decreased to 42.0 +/- 11.4% and the albumin-bound fraction increased to 56.4 +/- 11.2%. Total serum clearance increased during the same time period from a mean value of 1.5 to about 2.5 ml x min-1 x kg-1. The clearance of unbound LNG, however, remained unchanged. An examination of the free LNG concentrations revealed the same time course of LNG trough levels during the cycle as the simulated curve. This was derived from the pharmacokinetic parameters which were obtained after single dose administration. Thus, the present study showed that the pharmacokinetics of LNG can be fully explained on the basis of single dose pharmacokinetics and the changes in serum protein binding which were caused by a reduction of SHBG levels in the serum during chronic treatment with LNG.

Administration, Oral↗
PubMed1992

Contraceptives containing desogestrel or levonorgestrel have different effects on serum lipoproteins and post-heparin plasma lipase activities.

OBJECTIVE: We examined the effects of mono and polyphasic oral contraceptives containing desogestrel or levonorgestrel on serum lipoproteins, sex hormone binding globulin and post-heparin plasma lipase activities. DESIGN: The women took either desogestrel or levonorgestrel during the first menstrual cycle on days 15-28. They then received monophasic ethinyloestradiol plus either desogestrel or levonorgestrel for three cycles. After this, the women took sequential pills containing ethinyloestradiol plus either desogestrel or levonorgestrel for the three following cycles. Fasting blood samples were drawn pretreatment and at the end of each treatment. PATIENTS: The study group consisted of 30 apparently healthy women, aged 18-35. They were randomly divided into desogestrel and levonorgestrel groups, each consisting of 15 women. MEASUREMENTS: Cholesterol, triglyceride and phospholipids were determined in whole serum and in all lipoprotein fractions (following isolation of lipoproteins by ultracentrifugation). Plasma apolipoprotein A-I concentration, post-heparin plasma lipase activities and serum sex hormone binding globulin were also measured. RESULTS: Desogestrel (150 micrograms/day) did not change serum total triglyceride concentration, whereas levonorgestrel (150 micrograms/day) decreased it. Except for monophasic ethinyloestradiol plus levonorgestrel, the oestrogen-containing combinations increased serum triglyceride level. Low density lipoprotein (LDL) cholesterol remained stable with all treatments, but the cholesterol/triglyceride ratio of LDL decreased during all combinations with ethinyloestradiol. Levonorgestrel reduced total high density lipoprotein (HDL) cholesterol and both progestins reduced HDL2 cholesterol concentration. Addition of ethinyloestradiol reversed this change in the desogestrel but not in the levonorgestrel group. The polyphasic ethinyloestradiol plus levonorgestrel combination did not change total HDL cholesterol. Hepatic lipase was activated with either progestin when administered alone but its activity was suppressed below the baseline level when ethinyloestradiol was added. Conversely, both progestins suppressed sex hormone binding globulin levels, but addition of ethinyloestradiol caused marked increases above baseline. These increases were greater in women taking desogestrel than in those taking levonorgestrel. No treatment affected lipoprotein lipase activity significantly. CONCLUSIONS: Monophasic or polyphasic combinations of ethinyloestradiol and desogestrel do not have deleterious effects on serum lipoproteins. If levonorgestrel is used as the progestin component, polyphasic ethinyloestradiol plus levonorgestrel appears more favourable than monophasic ethinyloestradiol plus levonorgestrel.

Adolescent↗
PubMed1986

Sustained intrauterine release of levonorgestrel over five years.

Two models of levonorgestrel-releasing intrauterine devices were studied. Model A was designed to deliver 20 micrograms/day, and model B was designed to deliver 30 micrograms/day. Plasma concentrations of levonorgestrel were determined in blood samples taken from women who used the levonorgestrel-releasing intrauterine devices (IUDs) and who participated in a clinical trial for more than 5 years. During clinical studies IUDs have been removed for various reasons between 8 and 40 months after insertion. The rate of release of levonorgestrel from the IUDs was calculated by determining the remaining amount of levonorgestrel. Plasma concentrations of levonorgestrel ranged between a mean +/- standard deviation (SD) concentration of 166 +/- 75 pg/ml and 131 +/- 32 pg/ml for the first 18 months of use and between 101 +/- 37 pg/ml and 74 +/- 15 pg/ml at 24 and 60 months after insertion of the IUD. The plasma concentrations from 24 months through 60 months were significantly lower than concentrations measured during initial months of IUD use, but not between the two devices. There was a strong correlation between the time of use and the amount of levonorgestrel lost from the IUDs. The calculated mean daily release of levonorgestrel was 17.6 micrograms for model A and 22.2 micrograms for model B. This gives a calculated lifetime of more than 6 years for a levonorgestrel-releasing IUD.

Clinical Trials as Topic↗
PubMed1991

Effects of tamoxifen and levonorgestrel treatment on carbon tetrachloride induced alterations in rats.

Oestrogens cause progression in liver lesion, and thus ovariectomy improves hepatic injury both functionally and histologically. In the present study the efficacy of the antioestrogen tamoxifen (CAS 10540-29-1) was examined in chronical carbon tetrachloride damage. The results were compared with the effect of the progestogen levonorgestrel. Male Wistar rats were treated for 16 days. Blood sampling and autopsy were performed 2 h after last tamoxifen resp. levonorgestrel and 1 h after last CCl4 dosage. Tamoxifen diminished water content of the healthy liver. By fairly the same ratio it decreased high water content of the damaged liver. Levonorgestrel moderated water imbibition in CCl4 impairment. Tamoxifen caused protein synthesis in healthy and in injured liver. Levonorgestrel could not prevent protein loss associated with CCl4 damage. Tamoxifen counteracted, levonorgestrel moderated glycogen loss in liver lesion. Blood glucose was normal in all examined groups. Cytochrome P-450 decrease in CCl4 injury was moderated but not normalised by tamoxifen. Levonorgestrel was less effective. Cytochrome b5 content diminished in CCl4 lesion and both treatments restored it. Aminopyrine-N-demethylase was impaired by liver injury. An improvement was measured correlating with microsomal cytochrome P-450 content. This was significant with tamoxifen but not following levonorgestrel administration. The pathological serum bilirubin level of CCl4 lesion was normalised by tamoxifen as well as levonorgestrel treatment. The progestogen levonorgestrel moderated liver injury in reducing high water content, glycogen loss and normalising serum bilirubin. The antioestrogen tamoxifen seems to be a promising treatment in chronic hepatic impairment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminopyrine N-Demethylase↗
PubMed1987

Contraception with subdermal implants releasing levonorgestrel. A clinical and pharmacological study.

Two methods for release of levonorgestrel from polydimethylsiloxane (Silastic) subdermal implants for contraception were studied. The first system consists of six 3 cm long Silastic capsules filled with levonorgestrel (NORPLANT). The second one consists of two 4 cm long rods made from Silastic and levonorgestrel, covered with thin Silastic tubing (NORPLANT-2). The contraceptive efficacy of NORPLANT implants was excellent during the four years of observation. That of NORPLANT-2 implants was very good during the first three years, but not acceptable during the fourth year. Both types of implants were well tolerated and the most common side effect experienced was bleeding disturbances such as irregular bleeding and periods of prolonged bleeding. The frequency of such disturbances decreased considerably after the first year of use. The plasma levels of levonorgestrel decreased throughout the study, and did not show any statistically significant difference between users of the two types of implants. The plasma levels of levonorgestrel in women who became pregnant did not differ from those in women who did not become pregnant. Levonorgestrel binds to sex hormone binding globulin (SHBG) with high affinity, and in the bound form is not biologically active. A "free levonorgestrel index" (FLI), i.e. the ratio of plasma level of levonorgestrel to SHBG capacity, was calculated. Women with NORPLANT had higher FLI than those with NORPLANT-2 and women who became pregnant had lower FLI than those who did not. It is suggested that NORPLANT-2 implants have a lower rate of release of levonorgestrel than NORPLANT implants. SHBG capacity, thyroid binding proteins and corticosteroid binding globulin decreased during treatment. Plasma total testosterone decreased during treatment, whereas free testosterone was unaltered. Thyroid function and plasma cortisol levels did not change during treatment. Treatment with phenytoin decreased the contraceptive effect. In a group of regularly menstruating women who had used NORPLANT-2 implants for more than three years, 40% showed anovulation, 20% luteinization of unruptured follicles and 40% apparent ovulation.

Adolescent↗
PubMed1988

Reduced incidence of rabbit endometrial neoplasia with levonorgestrel implant.

To test the hypothesis that progestogens protect against the development of endometrial neoplasia, we placed polydimethylsiloxane implants (levonorgestrel or inert) into the right uterine horn at random in 114 old female rabbits. Cross-sectional uterine biopsy specimens were taken from both horns at the time of implantation and at 6, 12, and 24 months thereafter. Twenty-nine levonorgestrel-treated and 33 controls survived to the completion of the study. The incidence of endometrial neoplasia of 17.2% in the group treated with levonorgestrel was significantly less (p less than 0.05) than the 42.4% incidence observed in the control does. Before the completion of the study, one levonorgestrel-treated doe died and was found to have an endometrial tumor. When the findings of this doe are included in the report, the statistical significance is marginally lost. No endometrial neoplasia was found in the eight does with serum levonorgestrel concentrations greater than 0.12 ng/ml. Only one of the five tumors in the levonorgestrel-treated group occurred in the horn containing the levonorgestrel implant, which suggests that a dose effect is likely. Treatment with levonorgestrel decreases the incidence of endometrial neoplasia in rabbits. This finding gives further credence to the use of progestogen supplementation in women at risk for developing endometrial neoplasia.

Animals↗
PubMed1990

Effects of three combined oral contraceptive preparations containing desogestrel plus ethinyl estradiol on lipid metabolism in comparison with two levonorgestrel preparations.

The effects of three different desogestrel-containing combined oral contraceptive preparations on lipid metabolism were compared with those of two levonorgestrel preparations. The following preparations were studied: (1) monophasic desogestrel (150/30), (2) monophasic desogestrel (150/20, containing 20 micrograms of ethinyl estradiol instead of 30 micrograms of ethinyl estradiol, (3) biphasic desogestrel, (4) monophasic levonorgestrel (150/30), and (5) triphasic levonorgestrel. The effects of these preparations were assessed on high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein A-I, apolipoprotein B, the ratio of high-density lipoprotein cholesterol to low-density lipoprotein cholesterol, and the ratio of apolipoprotein A-I to apolipoprotein B after 3 months of treatment, and the percentage changes with regard to pretreatment were calculated. The monophasic desogestrel (150/30) and biphasic desogestrel preparations induced higher high-density lipoprotein cholesterol and apolipoprotein A-I levels than did their levonorgestrel-containing counterparts. Low-density lipoprotein cholesterol levels were increased in monophasic levonorgestrel and clearly decreased in the lowest ethinyl estradiol-containing monophasic desogestrel (150/20) and biphasic desogestrel preparations. Apolipoprotein B increased in all preparations. The antiatherogenic indexes (ratios of high-density lipoprotein cholesterol to low-density lipoprotein cholesterol and apolipoprotein A-I to apolipoprotein B were higher for monophasic desogestrel (150/30) and biphasic desogestrel than for comparable levonorgestrel-containing preparations. The differences seen between the desogestrel and levonorgestrel preparations can best be explained by the lower intrinsic androgenicity of 3-keto-desogestrel (active metabolite of desogestrel) than that of levonorgestrel.

Adult↗
PubMed1991

A comparison of flurbiprofen, tranexamic acid, and a levonorgestrel-releasing intrauterine contraceptive device in the treatment of idiopathic menorrhagia.

Treatment with flurbiprofen (100 mg twice a day for 5 days), tranexamic acid (1.5 gm three times a day for 3 days and 1 gm twice a day for another 2 days), and an intrauterine contraceptive device releasing 20 micrograms levonorgestrel per day was compared in women with idiopathic menorrhagia. The menstrual blood loss during two control periods in 15 women subsequently treated with flurbiprofen and tranexamic acid was 295 +/- 52 ml and 203 +/- 25.2 ml in the 16 women later fitted with a levonorgestrel-releasing intrauterine contraceptive device. Menstrual blood loss was reduced by all three forms of treatment. The reduction in menstrual blood loss expressed as a percentage of the mean of two control cycles for each form of treatment was as follows: flurbiprofen, 20.7% +/- 9.9%; tranexamic acid, 44.4% +/- 8.3%; levonorgestrel-releasing intrauterine contraceptive device after 3 months, 81.6% +/- 4.5%; levonorgestrel-releasing intrauterine contraceptive device after 6 months, 88.0% +/- 3.1%; levonorgestrel-releasing intrauterine contraceptive device after 12 months, 95.8% +/- 1.2%. The reduction in menstrual blood loss achieved by the levonorgestrel-releasing intrauterine contraceptive device was greater than that recorded with flurbiprofen (p less than 0.001) and tranexamic acid (p less than 0.01), and was greater for tranexamic acid when compared with flurbiprofen (p less than 0.05). The levonorgestrel-releasing intrauterine contraceptive device was the only form of treatment to reduce mean menstrual blood loss below 80 ml per menstruation, the upper limit of normal menstrual blood loss.

Adult↗
PubMed1992

Free levonorgestrel index and its relationship with luteal activity during long-term use of Norplant implants.

Levonorgestrel serum levels and sex hormone binding globulin (SHBG) were measured in 82 women during different years of use of Norplant implants. The ratio between levonorgestrel and SHBG was calculated as an indicator of the free biologically active fraction of levonorgestrel (free levonorgestrel index, FLI). These parameters were then correlated with the presence of luteal activity, as determined by progesterone levels above 9.6 nmol/L, in a sampling run of 10 samples taken twice a week for five consecutive weeks. Levonorgestrel serum levels remained constant around 1.0 nmol/L during the five-year period. SHBG levels were below normal for the first 18 months of use, returning to normal levels during the last three years of use. The FLI in the first two years was significantly higher than that observed in the later years. The frequency of cycles with luteal activity was 12% during the first 2 years, increasing to 44% in the latter years, when FLI levels were lower. Our results suggest that the changes in SHBG and consequently in the free biologically active fraction of levonorgestrel may largely account for the differences in degree of ovarian suppression observed between the first two years of use of Norplant implants and the latter three, even in the absence of a significant variation in total levonorgestrel concentrations.

Drug Implants↗