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PubMed1980

Levonorgestrel plasma concentrations and hormone profiles after insertion and after one year of treatment with a levonorgestrel-IUD.

Plasma concentrations of levonorgestrel, progesterone, estradiol, FSH and LH were measured in seven volunteers who had a levonorgestrel-releasing IUD inserted postmenstrually. Blood samples were collected twice weekly during a mean of 93 days immediately postmenstrually and during a mean of 41 days over the twelfth to fifteenth month of treatment. Patterns of bleeding were studied during the first year of treatment. The IUDs used were designed to release 25 micrograms/day of levonorgestrel. The mean +/- SD plasma concentration of levonorgestrel for all subjects during the first three months was 260 +/- 68 pg/ml, and 129 +/- 28 pg/ml after one year of treatment. During the initial period of blood sampling only two of the subjects ovulated, while only two did not ovulate after one year of treatment. Intermenstrual spotting occurred during the first sixty days of treatment. Three subjects developed amenorrhea at the end of the first year. All the subjects continued the use of the IUD and no pregnancies occurred.

Adult↗
PubMed1980

The effect of injectable norethisterone oenanthate on ovarian hormones in Thai women.

The ovarian hormones, progesterone and estradiol, as well as norethisterone concentrations were studied in 15 subjects receiving a single intramuscular injection of norethisterone oenanthate. Three treatment groups were studied. The 5 subjects of group A had no additional treatment, the 5 subjects of group B received ethynylestradiol and the 5 subjects of group C received combined ethynylestradiol and norgestrel orally. Additional treatment was for 5 consecutive days 6 weeks after the injection. Blood samples were obtained weekly for 12 weeks post-treatment. All subjects showed a similar pattern of norethisterone concentrations with a range of 3.5-19.5 ng/ml 1 week after injection, declining to levels of less than 0.02 ng/ml at the end of treatment period. Progesterone concentrations of greater than 4 ng/ml indicated that ovulation had occurred in 2 subjects of group A, 5 subjects of group B and 2 subjects of group C during the study period. Serum estradiol concentrations reached pre-ovulatory levels (greater than 200 pg/ml) in 4,3 and 2 subjects of group A,B and C, respectively, during the treatment period. With the other subjects, serum estradiol showed lesser increases. Among the 15 Thai women in the study, the median time of ovulation was 11 weeks, with the earliest occurring at 6 weeks. Three women receiving NET-OEN and no other treatment had ovulated by 6 weeks. Thai women in this study appear to be more resistant to the antiovulatory effect of NET-OEN as compared to women in other published studies.

Adult↗
PubMed1980

Clinical and endocrinologic study of continuous levonorgestrel administration from subcutaneous solid polydimethylsiloxane rods.

Three solid polydimethylsiloxane (Silastic) rods containing levonorgestrel were inserted into the subcutaneous tissue of the volar aspect of the forearm of 8 women. Serum samples were drawn three times a week for 2 months and weekly thereafter for 2 years in 3 of the subjects. The other subjects had serum drawn during the twelfth and last treatment months. Levonorgestrel, estradiol and progesterone were measured in all samples. The subject kept a bleeding record. In comparison to an earlier clinical trial in which 6 hollow capsules of Silastic filled with levonorgestrel were used, the 3 solid levonorgestrel-containing rods provided higher serum levels of levonorgestrel, fewer serum estradiol peaks, only a single episode of ovulation and better bleeding performance.

Adult↗
PubMed1980

A study of interaction of low-dose combination oral contraceptive with Ampicillin and Metronidazole.

Plasma levels of norethisterone (NET), ethinyl estradiol (EE), Ampicillin or Metronidazole were estimated in 16 women, who were taking low-dose oral combination contraceptive pills (containing norethisterone acetate 1 mg and ethinyl estradiol 30 microgram) and in whom concurrently, either Ampicillin (6 women) or Metronidazole therapy (10 women) was given. Neither Ampicillin nor Metronidazole therapy altered the 'peak' or 24-hour plasma levels and area under the curve, for NET and EE. Furthermore, oral contraceptive treatment did not alter the 'peak' levels of Ampicillin or Metronidazole. Progesterone (P) levels were in the anovulatory range in all Ampicillin treated cycles. However, in Metronidazole treated group, two out of 10 women showed a P rise of more than 4 ng/ml. The study was expanded to include another group of 15 women treated with Metronidazole, where only one women showed a P rise of more than 4 ng/ml. The occurrence of 'escape ovulation' as suggested by P rise of more than 4 ng/ml in three out of 25 Metronidazole treated women is either a chance incidence due to a different pharmacological response in them, or most probably due to the default in the regular intake of pills in these women. This is supported by the observation that one out of three women showing a P rise (greater than 4 ng/ml( during concurrent Metronidazole therapy, also showed ovulatory P values in oral contraceptive-only treated cycles. Furthermore, in the control group also, one out of 10 women had ovulatory P levels (greater than 4 ng/ml) in oral contraceptive-only treated cycles.

Adult↗
PubMed1980

The interaction of phenobarbital and other anticonvulsants with oral contraceptive steroid therapy.

In a group of 5 women on long-term anticonvulsant and oral contraceptive therapy, the plasma ethynylestradiol (EE) concentration on 50 microgram EE daily was 11.1 +/- 4.5 pg/ml. These values were at the lower end of the range found in normal women in this laboratory taking 30 microgram EE daily (6-190 pg/ml). Four women have been studied prospectively for 3 months, over 1 cycle before and 2 cycles during phenobarbital 30 mg b.i.d. therapy. Significant falls in the plasma EE concentration were seen in two women (from 104.8 +/- 13.4 to 37.7 +/- 2.0 pg/ml and from 125.6 +/- 23.8 to 34.8 +/- 6.7 pg/ml p less than 0.01) and breakthrough bleeding was seen in both women. No changes in plasma concentrations of follicle stimulating hormone, progesterone, norethindrone or norgestrel were seen. There was a significant increase in the sex hormone binding globulin capacity from 100.7 +/- 5.8 to 133.3 +/- 1.2 nmoles/1 (p less than 0.05). These changes are consistent with the known microsomal enzyme inducing effect of phenobarbital.

Adolescent↗
PubMed1980

Pharmacokinetic study of different doses of Depo Provera.

Doses of DepoProvera of 25, 50, 100 and 150mg were administered to four groups of women. The mean time for the return of follicular and luteal activity increased with increasing dose of DepoProvera. Luteal activity was suppressed for a longer period than follicular activity. None of the women receiving the two higher doses of DepoProvera showed a return of luteal function within 100 days of injection. The period for which medroxyprogesterone acetate (MPA) was detectable in serum increased with increasing dose but the values for the 100 and 150mg doses were not significantly different. There was a significant correlation between the concentration of MPA in blood and the return of follicular and luteal function. It is suggested that in the population studied, 100mg DepoProvera would be as effective as the usual 150mg dose and that injection of 50mg DepoProvera would provide a contraceptive effect for two months. The dose of MPA in the monthly injectable CycloProvera could be substantially reduced without loss of effectiveness.

Adult↗
PubMed1981

Pharmacokinetics of norethisterone oenanthate in humans.

The pharmacokinetics of a dose of 200 mg NET-OEN were studied after intramuscular injection into nine subjects. Blood levels of NET and NET-OEN increased rapidly, reaching peaks in most subjects within seven days. At all times after injection, serum levels of NET exceeded those of NET-OEN. The half-life of absorption varied from 5.4 to 22.3 days and the half-life of elimination varied from 7.5 to 22.5 days; there was a significant correlation (R = 0.78) between these two half-lives. There were significant correlations between the absorption half-lives and the peak values of NET and NET-OEN, the time to reach peak values and the time for which NET was detectable in serum. In all subjects NET was detectable in the circulation for a longer time after injection (mean value 74 days) than NET-OEN (mean value 43 days). The time for which the two steroids were detectable in the circulation showed a significant correlation with the elimination half-lives but there was no correlation with the peak values attained, the time taken to reach peak values and bioavailability. There was a two-fold variation between the subjects in the bioavailability of NET, less than 5% of the bioavailable NET was released after day 60.

Absorption↗
PubMed1981

Correlation between the serum norethindrone (NET) levels attained after insertion of a silastic implant releasing norethindrone acetate and the endogenous hormones particularly progesterone.

Six normally menstruating women were inserted each with a single silastic implant-D releasing norethindrone acetate (NETA). The levels of endogenous hormones, FSH, LH, E2 and progesterone, were estimated by radioimmunoassay (RIA) procedures in the control and treatment cycles. In addition, the levels of drug in the serum as norethindrone (NET) which is a major metabolite of NETA were also estimated by RIA procedures in the treatment cycles. In all, 12 treatment cycles were studied. In the initial treatment cycles (1st/2nd or 3rd), the serum NET levels were either 1 ng/ml or above. The LH and FSH showed either normal or suppressed mid-cycle peaks, but the progesterone levels were completely suppressed. In the sixth treatment cycles, the serum NET levels were either 0.5 ng/ml or below. The FSH and LH mid-cycle peaks were lower but distinct while the luteal progesterone levels were of normal ovulatory type. These studies lead us to the conclusion that a serum level of NET of the order of 1 ng/ml is required to bring about suppression of luteal progesterone, either as a result of direct action on the ovary or through suppression of pituitary gonadotropins. When the serum level falls to 0.5 ng/ml or below, the suppressive effect is removed and ovulatory pattern of progesterone returns.

Drug Implants↗
PubMed1982

A simple high-throughput enzymeimmunoassay for norethisterone (norethindrone).

A direct enzymeimmunoassay having the sensitivity required for determining norethisterone concentrations in small aliquots of plasma (10 microliter) has been developed. This assay featured a solid phase antiserum raised against a norethisterone-11 alpha-hemisuccinyl/bovine serum albumin conjugate. The antiserum was coupled to cyanogen bromide-activated magnetisable cellulose, and antibody-bound and free fractions were separated by a simple magnetic device. A norethisterone/horseradish peroxidase conjugate was used as the label; o-phenylenediamine/hydrogen peroxide being the substrate for colour development. The results obtained by this direct EIA, which allowed processing of at least 100 samples per day, were compared with those of a well-validated enzymeimmunoassay featuring solvent extraction and centrifugal separation of antibody-bound and free steroid; the results were in excellent agreement (n = 30; r greater than 0.99) suggesting the usefulness of the simple high-throughput procedure for processing the large sample numbers generated by field investigations and pharmacokinetic studies.

Centrifugation↗
PubMed1982

A preliminary pharmacological trial of the monthly injectable contraceptive cycloprovera.

A comparative pharmacological pilot study of the monthly injectable contraceptive CycloProvera was carried out in 11 women in four centres. There were no significant differences in the results between the centres except that the injection-bleeding interval appeared to be shorter in Swedish women than in those in Havana and Mexico. Medroxyprogesterone acetate was detectable in blood for 28 to 62 days after injection of CycloProvera and although follicular activity returned in less than 28 days after injection in many of the women, corpus luteum function was suppressed for at least seven weeks in all women. Most of the women retained a regular menstrual pattern; six of 33 cycles were amenorrhoeic. There was no significant change in any of the biochemical and haematological analyses.

Adult↗
PubMed1982

Effect of injectable norethisterone oenanthate (Norigest) on blood lipid levels.

Lipid concentrations were measured in 74 blood samples from 61 women who had been using the injectable contraceptive Norigest (norethisterone oenanthate) for between 2 to 4-1/2 years. There were no significant changes in the concentrations of total cholesterol, total triglycerides and low density and very low density lipoprotein cholesterol but high density lipoprotein cholesterol was significantly reduced. The reduction in serum HDL-C levels was not correlated with either the serum norethisterone concentrations or the length of use of Norigest nor was it affected by obesity or smoking.

Adult↗
PubMed1982

Pharmacokinetic and pharmacodynamic investigations with vaginal devices releasing levonorgestrel at a constant, near zero order rate.

The pharmacokinetic and pharmacodynamic effects of vaginal devices releasing levonorgestrel (L-NOG) at a constant rate (in vitro release: approximately 20 micrograms/day) were studied in a group of 20 normally menstruating women during a period of 90 days of continuous use. Peripheral blood samples were withdrawn two or three times (in the great majority of subjects, on Mondays, Wednesdays and Fridays) during a pretreatment (control) cycle, during 90 days of exposure and during the first week following the removal of the device, and the levels of L-NOG, estradiol and progesterone were analyzed by radioimmunoassay techniques. In 8 of these subjects, endometrial biopsies were also taken during days 23 to 25 of the control cycle, and then 6 and 10 weeks following the insertion of the devices. In addition, the initial absorption rate and removal half-life of L-NOG were assessed in 7 subjects using the devices for a period of 8 days only. Following insertion of the devices, the levels of L-NOG rose very rapidly, and reached the final "plateau" in some 30 minutes' time. This was followed by a limited period of "burst" with doubling the levels for a few hours, after which the levels remained stable and diminished very slowly in a linear fashion with an average decline of 23-26% during 90 days, corresponding to a daily decrease of 0.2 to 0.3 per cent. The removal half-life (first compartment) after 90 days of exposure in 19 subjects was 16.1 (13.7-18.6) hours. Sixty-nine treatment segments of 30 days were studied with frequent hormone assays; of these, 20 (or 29%) were anovulatory, 13 (19%) exhibited inadequate luteal function, and 32 (52%) had normal ovulatory-like cycles. All endometrial biopsies obtained during the pretreatment cycle were normal secretory; of the 16 biopsies obtained during treatment, 4 were suppressed, 2 proliferative, 6 secretory, and 4 could not be dated because of bleeding. An assessment of the bleeding profiles during exposure to L-NOG revealed almost a doubling of the number of days with bleeding and spotting (35% compared to 18% during the pretreatment cycle). However, significantly more frequent bleeding was found in the 20 anovulatory segments (37.3%) than in the 36 normal ovulatory-like ones (27.7%). It is concluded that differences in the frequency of bleeding and spotting with low-dose progestogens may reflect differences in the frequency of ovulation inhibition just as much as differences in the hormonal profiles of the compounds administered.

Adult↗
PubMed1983

Norethisterone levels in maternal serum and milk after intramuscular injection of norethisterone oenanthate as a contraceptive.

There is concern that the breast-fed infant whose mother is receiving intra-muscular progestogens for contraception will be exposed to significant quantities of the steroid. Norethisterone levels in maternal serum and milk were studied throughout an injection interval after intramuscular administration of 200mg norethisterone oenanthate. Milk samples were taken at the beginning and at the end of the feed. Norethisterone concentrations in milk were very much lower, but declined more slowly, than serum concentrations. Post-suckling concentrations were higher than pre-suckling concentrations. Experiments in adults receiving an oral dose of norethisterone in cow's milk comparable to that ingested by an infant in a day resulted in low serum levels. It is concluded that only very low concentrations of norethisterone would be present in the infant's circulation.

Breast Feeding↗
PubMed1984

Hormonal consequences of missing the pill during the first two days of three consecutive artificial cycles.

The hormonal effects of the deliberate omission of a low-dose combined oral contraceptive pill (30 micrograms ethinyl estradiol + 150 micrograms levonorgestrel) during the first two days of three consecutive artificial cycles were studied in 10 women. The plasma levels of estradiol, progesterone, levonorgestrel and--whenever justified--of LH were measured three times weekly (Mondays, Wednesdays and Fridays) throughout a 90-day period, and the ovarian reaction to the prolongation of the pill-free period from 7 to 9 days was assessed. One subject (with a premature LH surge) showed a marked follicular and an inadequate luteal activity in 2 of 3 cycles. The remaining cycles were characterized by a varying degree of follicular activity associated with the absence of any luteal function. None of the subjects exhibited peripheral steroid levels indicating a normal ovulatory cycle. The results are interpreted as suggesting that repeated prolongation of the pill-free period from 7 to 9 days might result in a gradual increase in ovarian activity.

Adult↗
PubMed1984

Biotransformation of norgestimate in women.

The metabolism of norgestimate (ORF-10131; 14C-d-13-ethyl-17-acetoxy-18,19-dinor-17 alpha-pregn-4-en-20- yn -3-oxime) was studied in humans. Compound labeled with carbon-14 in the 17 alpha-ethynyl group was administered to four female subjects. An average of 46.8 percent of the administered radioactivity was excreted in the urine and 36.8 percent in the feces over a two-week collection period. About 12 percent of the urinary radioactivity represented freely extractable metabolites and another 57 percent consisted of extractable material released by enzyme hydrolysis. The ethynylated metabolites of norgestimate were separated from endogenous compounds and non- ethynylated metabolites by silver- sulfoethyl cellulose column chromatography. Metabolites were subsequently isolated by high performance liquid chromatography and thin layer chromatography. The identification of five urinary metabolites was accomplished by combined gas-liquid chromatography/mass spectrometry. These metabolites include norgestrel, 16 beta- hydroxynorgestrel , 2 alpha- hydroxynorgestrel , 3 alpha, 5 beta- tetrahydronorgestrel , and a fifth trihydroxylated metabolite of undetermined stereochemical configuration; 3,16-dihydroxy-5- tetrahydronorgestrel .

Biotransformation↗
PubMed1985

The interaction between sex hormone binding globulin and levonorgestrel released from vaginal rings in women.

The levels of levonorgestrel (L-NOG), progesterone and estradiol were measured in plasma samples of 17 normally menstruating women during a control cycle and during a subsequent period (90 days) with a L-NOG-releasing vaginal ring. During days 38-66 after the insertion of the vaginal ring the concentrations of sex hormone binding globulin binding sites (hereafter: SHBG levels) were also assayed. Significant correlations were found not only between the corresponding levels of SHBG and L-NOG during exposure to the latter compound (r = 0.44; P less than 0.05), but also between the levels of SHBG in the control cycle and the levels of L-NOG measured during exposure (r = 0.60; P less than 0.01). Furthermore, the decrease in SHBG levels during the vaginal administration of L-NOG was directly proportional to the levels of SHBG in the pretreatment cycle (r = 0.64; P less than 0.01). A significant relationship was found between the levels of L-NOG (and, hence - indirectly - the levels of SHBG) and the degree of suppression of ovarian function. Thus the levels of L-NOG were lower (P less than 0.01) in the subjects (n = 8) with an apparently normal or partially suppressed ovulatory-like pattern of progesterone than in those subjects (n = 9) in whom progesterone levels were completely suppressed.

Adult↗
PubMed1986

Enhanced metabolism of levonorgestrel during phenytoin treatment in a woman with Norplant implants.

A 26-year-old woman, treated with phenytoin for 10 years because of epilepsy, had Norplant subdermal implants inserted after a legal abortion. She became pregnant again after nine months of Norplant use. Her plasma levonorgestrel (LNG) levels were followed during one month during phenytoin treatment and then later during one month after discontinuation of phenytoin. During phenytoin treatment, plasma LNG levels were markedly below the levels found in healthy women with Norplant. There was a pronounced, statistically significant increase in plasma LNG levels after discontinuation of phenytoin. The plasma levels of sex hormone binding globulin were markedly above those found in normal healthy women during treatment with phenytoin and decreased significantly after cessation of phenytoin. The effects on the pharmacokinetics of LNG were reflected by effects on the menstrual cycle. During phenytoin treatment, the woman had regular ovulatory menstrual cycles. After cessation of phenytoin, her cycles became irregular and during the study period of one month, no signs of ovulation were found. It is concluded that treatment with phenytoin during use of Norplant subdermal implants enhances the metabolism of LNG to an extent where the contraceptive efficacy is endangered.

Adult↗