[Levonorgestrel-releasing subcutaneous implants. First year's experience]

This multicentric study was done in order to know the anticonceptive efficacy and side effects of subdermic implants liberating levonorgestrel, in Mexican women. Results analysis, at one year, of 246 women, at four medical centers of Mexican Institute of Social Security (IMSS), showed that this anticonceptive is highly efficacious, as there were no pregnancies in 2326 months of observation. The main side effects were: menstrual disorders in 34.8% of women; soreness in implantation site in 3.6%; headache in 13.4% and nausea, dizziness and vomiting in 11.6%. The most frequent causes for implant retirement were menstrual cycle alterations, and soreness at implantation site, with 7.3 and 3.5 respectively. The continuity rate at one year was 84.3, which was higher to what has been seen at the Institution with other temporal anticonceptive methods, so the implants may be considered as one more alternative in family planning methods.

A comparative study on the effects of a monophasic pill containing desogestrel plus 20 micrograms ethinylestradiol, a triphasic combination containing levonorgestrel and a monophasic combination containing gestodene on coagulatory factors

The changes in haemostasis during oral contraception are related to the ethinylestradiol dose present in the formulation taken by the patient. An open, randomized longitudinal study was performed to evaluate and compare the effects that low-dose oral contraceptives (OCs) containing different doses of ethinylestradiol exert on the haemostatic system. Eighty-nine healthy women, aged 18-45 years, were randomly assigned to treatment with 3 different OCs: a monophasic pill containing 30 micrograms of ethinylestradiol plus 75 micrograms of gestodene (GSD/30) (30 subjects), a triphasic pill containing levonorgestrel (TRI/LNG) (28 subjects), a monophasic pill containing 20 micrograms ethinylestradiol plus 150 micrograms of desogestrel (DOG/20) (31 subjects). From every woman, blood samples were collected before treatment and at the 3rd and 6th cycle of pill intake. The number of platelets significantly increased (p less than 0.01) during treatment with TRI/LNG. Fibrinogen plasma values were significantly increased (p less than 0.05) only in women treated with the preparation GSD/30. Fibrinopeptide A (FPA) plasma levels significantly increased (p less than 0.01) during treatment with the pills TRI/LNG and GSD/30, but the levels of FPA were unchanged in the group treated with DOG/20. The overall results of this study confirm that the effects of OCs on haemostasis are dependent on the ethinylestradiol dose. Moreover, they suggest that with reduction of the ethinylestradiol component to 20 micrograms, the effects of OCs on haemostasis seem to be virtually eliminated.

Binding of oral contraceptive progestogens to serum proteins and cytoplasmic receptor

Some progesterones widely used in oral contraceptives are characterized at the level of high-affinity receptor binding as well as binding to sex hormone-binding globulin and corticosteroid-binding globulin. With regard to binding to sex hormone-binding globulin, gestodene, levonorgestrel, and to a lesser extent 3-ketodesogestrel (which is only formed from the prodrug desogestrel in the body), show a behavior that is manifested in the relatively high affinity to sex hormone-binding globulin, whereas desogestrel and norgestimate do not display any measurable affinity for this specific steroid-binding serum protein. Furthermore, levonorgestrel and gestodene dissociate very much more slowly from the binding sites of sex hormone-binding globulin than 3-ketodesogestrel. A natural affinity of all these synthetic progestogens tested for corticosteroid-binding globulin could not be established. Gestodene, levonorgestrel, and 3-ketodesogestrel bind to the progesterone, glucocorticoid, and androgen receptor with high affinity, apart from slight differences, whereas estrogen receptor affinity could not be demonstrated in any of the progestogens investigated. In relation to aldosterone, the relative binding affinity values of gestodene, levonorgestrel, and the natural progestogen progesterone are relatively high, whereas 3-ketodesogestrel does not display any measurable affinity for this receptor species.

Pharmacologic and pharmacokinetic characteristics of norgestimate and its metabolites

Biotransformation, pharmacologic, and pharmacokinetic studies of norgestimate and its metabolites indicate that 17-deacetyl norgestimate, along with the parent drug, contributes to the biologic response. The postulated metabolic pathway, which is based on the identification of urinary products had indicated that three metabolites of norgestimate, 17-deacetyl norgestimate, 3-keto norgestimate, and levonorgestrel, might participate in the response. The pharmacologic evaluation of these metabolites demonstrates that only 17-deacetyl norgestimate has a pharmacologic profile consistent with that of norgestimate, and significant concentrations of this metabolite have been measured in the serum of women after the administration of norgestimate. These studies indicate that 17-deacetyl norgestimate contributes to the pharmacologic response to norgestimate.

Serum pharmacokinetics of orally administered desogestrel and binding of contraceptive progestogens to sex hormone-binding globulin

Serum levels of 3-ketodesogestrel and ethinyl estradiol were analyzed by radioimmunoassay in a balanced crossover study with two tablet formulations containing desogestrel (0.150 mg) and ethinyl estradiol (0.030 mg) in 25 women under steady-state conditions after 21 days of treatment. The pharmacokinetic properties of desogestrel were characterized by the following parameters: (1) maximum serum concentration, (2) time to maximum serum concentration, (3) total area under the serum concentration versus time curve, and (4) serum half-life of elimination. The interindividual variation in these parameters was comparable with that observed with other contraceptive combinations containing ethinyl estradiol and norethisterone, levonorgestrel, or gestodene. The serum distribution of contraceptive progestogens is known to be determined by their affinity to sex hormone-binding globulin and the concentration of sex hormone-binding globulin. We analyzed the structural features that determine binding to sex hormone-binding globulin. The 18-methyl group increased and the 11-methylene group weakened the binding to sex hormone-binding globulin. The double bond at C-15 reinforced the binding only when combined with an 18-methyl group. Therefore, the binding of levonorgestrel (the 18-methyl derivative of norethisterone) and gestodene (the delta-15,18 methyl derivative of norethisterone) to sex hormone-binding globulin was much stronger than that of 3-keto-desogestrel and norethisterone.

Gonadotropin and estradiol secretion during the week of placebo therapy in oral contraceptive pill users

The changes in the hypothalamic-pituitary-ovarian axis during the placebo week in oral contraceptive pill users were assessed. Fifteen women using the combined oral contraceptive pill were studied for eight hours at the start and at the end of the placebo week and gonadotropin secretion and estradiol concentrations were compared with those in control women in the follicular phase of an unmedicated menstrual cycle. Both gonadotropin and estradiol concentrations were suppressed at the start of the placebo week. By day 7 of placebo, gonadotropin concentrations and pulse patterns were indistinguishable from those of the control subjects although estradiol concentrations were still significantly lower.

Pharmacokinetics of the contraceptive steroids levonorgestrel and gestodene after single and multiple oral administration to women

Little is known about the pharmacokinetics of the two progestins levonorgestrel and gestodene during long-term administration compared with single-dose pharmacokinetics. The predictive value of single-dose administration for the pharmacokinetic behavior of a progestin during long-term treatment was investigated for two triphasic oral contraceptives. One contained levonorgestrel and the other gestodene, each in combination with ethinyl estradiol. In eight Japanese women who received the levonorgestrel-containing formulation over a treatment cycle, steady-state trough levels of levonorgestrel were higher than those obtained by computer simulation based on single-dose administration. An analogous observation was made in a group of 10 white women who received the gestodene-containing formulation. A close correlation between gestodene and sex hormone-binding globulin concentrations was demonstrated for eight subjects; the other two patients already had initially high sex hormone-binding globulin levels. Ethinyl estradiol-induced production of sex hormone-binding globulin seems to be a major factor that contributes to the accumulation of the two progestins in the plasma. Computer simulation, based on single-dose pharmacokinetics, allows an estimation of this contribution.

Pharmacokinetics and pharmacodynamics of oral contraceptive steroids: factors influencing steroid metabolism

The time-dependent alterations in the serum concentrations of ethinyl estradiol, gestodene, and 3-keto-desogestrel during treatment with 30 micrograms of ethinyl estradiol + 75 micrograms of gestodene or 30 micrograms of ethinyl estradiol + 150 micrograms of desogestrel were investigated during 12 months. The levels of gestodene and 3-keto-desogestrel increased between days 1 and 21 of each cycle, reaching maximal levels during the third and sixth cycles. The serum concentrations of gestodene were fourfold to fivefold higher than those of 3-keto-desogestrel. The ethinyl estradiol levels increased significantly between days 1 and 10 during each cycle and were significantly higher by 70% during intake of ethinyl estradiol/gestodene compared with ethinyl estradiol/desogestrel, although the dose was identical. Intake of gestodene, in addition to 35 micrograms of ethinyl estradiol + 2 mg of cyproterone acetate, caused a rise in ethinyl estradiol levels. During treatment with ethinyl estradiol/gestodene and an additional 150 micrograms of levonorgestrel, there was a continuous increase in gestodene levels, although sex hormone-binding globulin level did not change. During treatment with 30 or 35 micrograms of ethinyl estradiol and 75 micrograms of gestodene, 150 micrograms of desogestrel, or 2 mg of cyproterone acetate, there were large intraindividual and interindividual variations in the steroid levels and ratios of estrogen: progestogen levels. There was no correlation with the occurrence of intermenstrual bleedings. It is concluded that ethinyl estradiol and nortestosterone derivatives may inhibit steroid-metabolizing enzymes in the liver, which results in a rise in the serum levels of contraceptive steroids. The cause of the large intraindividual variations is as yet unknown, but it is probably from changes in steroid metabolism.

Norplant contraceptive implants--a comparison of capsules versus rods in Singapore

The NORPLANT system is one of the most modern long acting steroidal fertility regulatory delivery systems to be introduced. It consists of six silicone capsules. The NORPLANT-2 rod system on the other hand consists of only 2 rods. The comparative study undertaken suggests that the NORPLANT-2 rod system is highly effective, safe and acceptable as the NORPLANT six capsule system in Singapore. It would thus appear that the NORPLANT-2 rod system as compared to the NORPLANT six capsule system has a great potential for acceptability in terms of ease of insertion and removal.

Modern trends in contraception

Substantial improvements have been made in oral contraceptives, a new injectable contraceptive (Norplant), and the intrauterine device (IUD). Major risks with oral contraceptives have declined substantially, and a number of noncontraceptive health benefits have been discovered. Norplant is probably the first new contraceptive in recent years, and offers long-term contraception with high efficacy and modest risks. The IUD, by carefully selecting users, is a safe and efficacious contraceptive method. The major risk, pelvic inflammatory disease (PID), is far less common if one avoids use in the presence of risk factors for PID.

The interaction of phenytoin and carbamazepine with combined oral contraceptive steroids

Patients taking oral contraceptive steroids (OCS) are known to suffer contraceptive failure while taking anticonvulsants such as phenobarbitone, phenytoin and carbamazepine. We have studied the single dose kinetics of ethinyloestradiol (EE2); 50 micrograms, and levonorgestrel (Ng); 250 micrograms in groups of women before and 8-12 weeks after starting therapy with phenytoin (n = 6) and carbamazepine (n = 4). The area under the plasma concentration-time curve (AUC) was measured over a 24 h period for each steroid and significant reductions were seen with both anticonvulsants. Phenytoin reduced the AUC for EE2 from 806 +/- 50 (mean +/- s.d.) to 411 +/- 132 pg ml-1 h (P less than 0.05) and for Ng from 33.6 +/- 7.8 to 19.5 +/- 3.8 ng ml-1 h (P less than 0.05). Carbamazepine reduced the AUC for EE2 from 1163 +/- 466 to 672 +/- 211 pg ml-1 h (P less than 0.05) and for Ng from 22.9 +/- 9.4 to 13.8 +/- 5.8 ng ml-1 h (P less than 0.05). These changes are compatible with the known enzyme inducing effects of phenytoin and carbamazepine. Patients taking these anticonvulsants will need to be given increased doses of OCS (equivalent to 50-100 micrograms EE2 daily) to achieve adequate contraceptive effects.

The effects of different formulations of oral contraceptive agents on lipid and carbohydrate metabolism

BACKGROUND

Oral contraceptives can induce changes in lipid and carbohydrate metabolism similar to those associated with an increased risk of coronary heart disease, including increased serum triglyceride, low-density lipoprotein (LDL) cholesterol, and insulin levels and decreased high-density lipoprotein (HDL) cholesterol levels. In this study, we examined whether modification of the type or dose of progestin in oral-contraceptive preparations diminishes these changes.

METHODS

We measured plasma lipoprotein levels and performed oral glucose-tolerance tests in a cross section of 1060 women who took one of nine types of oral contraceptives for at least three months and 418 women who took none. Seven of the contraceptive formulations contained various doses and types of progestin: levonorgestrel in low (150 micrograms), high (250 micrograms), and triphasic (50 to 125 micrograms) doses; norethindrone in low (500 micrograms), high (1000 micrograms), and triphasic (500 to 1000 micrograms) doses; and a new progestin, desogestrel, in one dose (150 micrograms). All seven contained 30 to 40 micrograms of ethinyl estradiol. Two additional formulations contained progestin alone.

RESULTS

As compared with controls, women taking combination drugs did not have increased serum total cholesterol levels but did have increases of 13 to 75 percent in fasting triglyceride levels. Levels of LDL cholesterol were reduced by 14 percent in women taking the combination containing desogestrel and by 12 percent in those taking low-dose norethindrone. Levels of HDL cholesterol were lowered by 5 percent and 16 percent by the combinations containing low-dose and high-dose levonorgestrel, respectively; these decreases were due to reductions of 29 percent and 43 percent, respectively, in the levels of HDL subclass 2. The combination pill containing high-dose norethindrone did not affect HDL cholesterol levels, whereas that containing low-dose norethindrone increased HDL cholesterol levels by 10 percent. The desogestrel combination increased HDL cholesterol levels by 12 percent. Levels of apolipoproteins A-I, A-II, and B were generally increased by combination drugs. Depending on the dose and type of progestin, combination drugs were associated with plasma glucose levels on the glucose-tolerance test that were 43 to 61 percent higher than in controls, insulin responses 12 to 40 percent higher, and C-peptide responses 18 to 45 percent higher. Progestin-only formulations had only minor metabolic effects.

CONCLUSIONS

The appropriate dose and type of progestin may reduce the adverse effects of oral contraceptives on many metabolic markers of risk for coronary heart disease. Progestin-only formulations or combinations containing desogestrel or low-dose norethindrone were associated wtih the most favorable profiles.

Clinical experience with the progestogen-only pill

Experience with the progestogen-only pill (POP) in a family planning clinic is presented. From the clinic records, 408 women were identified who had opted to use a POP. Of these, 50 women had used the POP during lactation and these were excluded from the analysis. The remaining 358 women used the POP for up to 150 months, giving a total of 18,125 women-months of use. Three pregnancies occurred, giving a Pearl Index of 0.2 per 100 women-years. Non-menstrual side effects were minor and were reported by 77 women. For the women who discontinued the POP, the main reason was menstrual irregularity (47.5%). However, despite the long-term use by most of the women, almost 40% maintained a mostly regular menstrual pattern. Our findings suggest that the POP provides a very acceptable method of oral contraception for many women and that it should be more actively promoted.

Low-dose oral contraceptives lower plasma levels of apolipoprotein E

Three different oral contraceptive preparations were studied before and after a 3 month treatment period with respect to their effects on plasma lipoprotein parameters. A total of 58 healthy women requesting oral contraception were randomly assigned to three groups. Each woman received either monophasic preparations containing ethinylestradiol and desogestrel (M-DG); ethinylestradiol and gestodene (M-GD); or a triphasic preparation of ethinylestradiol and levonorgestrel (T-LN). As has been reported in other studies, the concentrations of total plasma cholesterol and apolipoproteins B and A-IV did not change significantly in any group. HDL cholesterol, triglycerides, apolipoproteins A-I and A-II increased or tended to increase. Despite the effects of the three hormone preparations on these lipoprotein parameters, however, each led to a highly significant decrease in apolipoprotein E plasma levels. Considering the recently reported observations that oral contraceptives increase the hepatic uptake of cholesterol-rich remnants, this decrease in apo-E plasma levels may in women that take oral contraceptives be directly correlated with increased hepatic lipoprotein metabolism.

Pharmacokinetics and biotransformation of orally administered oestrone sulphate and oestradiol valerate in post-menopausal women

The pharmacokinetic properties and biotransformation of two orally active oestrogens, piperazine oestrone sulphate (PE1S, 2.5 mg/day) and oestradiol valerate (E2V, 2.0 mg/day), given alone or in combination with levonorgestrel (LNG, 250 micrograms/day) were compared in 8 post-menopausal women, using a randomized cross-over design. The end points measured in peripheral plasma included oestrone (E1), oestradiol (E2), oestriol (E3), oestrone sulphate (E1S), oestradiol sulphate (E2S) and oestriol sulphate (E3S). In addition, LNG and sex-hormone-binding globulin SHBG concentrations were also assessed. The plasma levels of E3 were invariably below the detection limit (220 pmol/l). The levels of all the other oestrogens analyzed were consistently higher and the area under the curve significantly greater (except in the case of E3S) following PE1S administration than those recorded after E2V ingestion. The terminal half-lives of the circulating oestrogens measured after PE1S administration did not differ from those found after E2V administration. After 21 days of PE1S administration (in combination with LNG for the last 10 days), the maximum levels of all the oestrogens (except those of E2) were significantly higher than those seen after the first dose. No such difference was observed after E2V administration. There was no difference between the effects of the two treatment regimens with regard to the E1/E2 ratios, but the E1/E1S ratios were significantly lower after PE1S treatment than after E2V administration. It is concluded that, compared with an equivalent dose of PE1S, daily repeated oral administration of E2V yields consistently lower peripheral plasma levels of E2 and its principal metabolites. However, in contrast to PE1S therapy, prolonged administration of E2V does not result in an accumulation of the circulating oestrogens measured.

A comparative study of the effects of a monophasic and a triphasic oral contraceptive containing ethinyl estradiol and levonorgestrel on lipid and lipoprotein metabolism

A comparative study of the effects of a monophasic and a triphasic oral contraceptive containing ethinylestradiol (EE) and levonorgestrel (LNG) on lipid and lipoprotein metabolism was conducted on 45 Singapore women under the WHO Special Programme of Research in Human Reproduction. The women were randomly allocated to one of the two pill groups--a triphasic preparation containing low doses of LNG and EE in various proportions and a monophasic preparation of 150 micrograms LNG and 30 micrograms EE, and an additional 18 women, choosing to use IUDs, were recruited as controls. Blood samples were taken at admission, 3 and 12 months thereafter. For both pill groups, total cholesterol decreased with duration of use, while HDL cholesterol decreased slightly at 3 months and thereafter increased. LDL cholesterol decreased slightly at 3 months, returning to baseline at 12 months for the monophasic group, while remaining unchanged at 12 months for the triphasic group. The monophasic preparation appeared to lower total, LDL and HDL cholesterols to a greater extent at 3 months than the triphasic preparation. Compared with IUD users, for the monophasic group, both total and HDL cholesterols were significantly lower at 3 months and HDL and LDL cholesterols were lower at 12 months. In addition, ratios of HDL cholesterol/LDL cholesterol and HDL cholesterol/total cholesterol were significantly lower at 12 months. Changes in triglycerides were minimal for both pill groups. However, at 3 months, triglycerides for the triphasic group were significantly higher than the IUD users, but this observation was not of any clinical importance since comparison of changes with their respective pretreatment values were not statistically significant. These results indicate that these changes are related to the dosage and estrogen-progestogen ratio of the preparation. Furthermore, the monophasic preparation may have a disadvantage over the triphasic preparation since it appears to cause more disturbance in lipid metabolism. However, it is noted that these changes in lipids and lipoproteins were minimal and did not appear to be of any clinical significance.

The influence of different combined oral contraceptives on the prevalence and severity of dysmenorrhea

The influence of different oral contraceptives (OC) on the prevalence and severity of dysmenorrhea was investigated longitudinally (from age 19 to 24 years) in a representative sample of young women from an urban Swedish population. The women were grouped according to the type of OC used at the time of assessment: monophasic OC with low gestagen activity; progestogen-dominated monophasic OC; triphasic OC; neither OC nor an intrauterine device (IUD). At the age of 19 years, the severity of dysmenorrhea was lower in users of monophasic OCs with low gestagen activity (p less than 0.05) and users of progestogen-dominated monophasic OCs (p less than 0.001) compared to women who used neither OC nor an IUD. At 24 years of age, the severity of dysmenorrhea was lower in users of monophasic OCs with low gestagen activity (p less than 0.001), users of progestogen-dominated monophasic OCs (p less than 0.001) and users of triphasic OCs (p less than 0.001), compared to women who used neither OC nor an IUD. The severity of dysmenorrhea in women who did not use an OC or IUD when 19 years old was reduced in the same women who used OCs when 24 years old, compared (p less than 0.001) to women who still used neither an OC nor an IUD. There were no significant differences in the prevalence and severity of dysmenorrhea between the users of monophasic OCs, irrespective of progestagen activity, and users of triphasic preparations.

Long-term contraception with the levonorgestrel 20 mcg/day (LNg 20) and the copper T 380Ag intrauterine devices: a five-year randomized study

An intrauterine device, releasing approximately 20 micrograms/day of levonorgestrel (LNg 20), used by 1124 women, was studied in a randomized trial of five years duration in comparison with the Copper T, model TCu 380Agm in 1121 women. At five years, the gross cumulative pregnancy rate of 1.1 +/- 0.5 per 100 among users of the LNg 20 devices was not significantly different from the rate of 1.4 +/- 0.4 per 100 experienced by users of the Copper T 380Ag. The steroid-releasing IUD had significantly higher termination rates for expulsion and amenorrhea, a significantly lower termination rate for other menstrual problems and pain, and a lower continuation rate. The five-year continuation rate among women using the TCu 380Ag was 40.6 per 100 as compared with that of 33.0 per 100 among women randomized to the LNg 20 device (P less than .001). Terminations attributed to amenorrhea with the LNg device primarily account for differences in continuation. These two intrauterine devices are the most effective long-term, reversible IUDs yet reported in the literature. No other contraceptive methods have exhibited such low long-term pregnancy rates in randomized comparative trials.