Ovarian activity during regular oral contraceptive use

The aim of this study was to assess whether during regular OC use ovarian activity might lead to ovulation, as assessed by ultrasound (US) evaluation of follicular growth and blood levels of 17-beta-estradiol and progesterone. A total of 51 healthy women with normal menstrual cycles (28 +/- 3 days) and no gynecological symptoms were recruited. A total of 22 patients were given a triphasic OC pill containing 35 mg ethinyl estradiol (EE) and 50 mg desogestrel (DSG) in the first seven tablets; 30 mg EE and 100 mg DSG in tablets 8 to 14, and 30 mg EE and 150 mg DSG in tablets 15 to 21; 29 patients received one of two OC pills, both containing 20 mg EE plus 150 mg DSG (15 patients) or 75 mg of gestodene (14 patients). A total of 86 cycles were monitored: 51 during the 3rd-4th cycle and 35 during the 6th-8th cycle of OC treatment. Follicular-like structures were observed in nine patients. The frequency of follicular-like structures was similar during the 3rd-4th cycle (9%) and during the 6th-8th cycle (11%). There was no relationship between follicular growth and blood levels of E2 and progesterone, which always appeared suppressed. In conclusion, the results of this study suggest that during OC use (even with low dose of ethinyl estradiol), a little ovarian activity may be present without ovulation.

Establishing the minimum effective dose and additive effects of depot progestin in suppression of human spermatogenesis by a testosterone depot

Hormonally induced azoospermia induced by weekly im injections of testosterone enanthate provides effective and reversible male contraception, but more practical regimens are needed. Given our previous findings that six 200-mg pellets implanted subdermally produced more stable, physiological T levels and reduced the delivered T dose by more than 50% while maintaining equally effective suppression of sperm output with fewer metabolic side-effects than weekly 200-mg testosterone enanthate injections, we sought in this study to determine 1) whether further dose-sparing could be achieved by lower testosterone doses while maintaining efficacy and 2) the efficacy of adding a depot progestin to a suboptimally suppressive depot testosterone dose as a model depot progestin/androgen combination male contraceptive. Healthy volunteers were randomized into groups (n = 10) who received either of two lower T doses (two or four 200-mg T pellets) or four 200-mg T pellets plus a single im injection of 300 mg depot medroxyprogesterone acetate (DMPA). Two T pellets (400 mg, 3 mg/day) had a negligible effect on sperm output. Four T pellets (800 mg, 6 mg/day) suppressed sperm output between the second to fourth postimplant months; output returned to normal by the seventh postimplant month, although only 4 of 10 men became azoospermic or severely oligozoospermic (< 3 mol/L/mL). The addition of a depot progestin markedly increased the extent, but not the rate, of sperm output suppression, with 9 of 10 becoming azoospermic and 10 of 10 becoming severely oligozoospermic. There were no serious adverse effects during the study. Plasma total and free testosterone levels remained within the eugonadal range at all times with each treatment. Plasma epitestosterone was suppressed by all 3 regimens, consistent with a dose-dependent inhibition of endogenous Leydig cell steroidogenesis. Plasma LH and FSH measured by a two-site immunoassay were suppressed in a dose-dependent fashion by T and further suppressed by the addition of DMPA. Sex hormone-binding globulin levels were decreased by DMPA, but not by either T dose. Prostate-specific antigen and lipids (total, low or high density lipoprotein cholesterol, and triglycerides) were not significantly changed in any group. Thus, a depot testosterone preparation with zero order release must be delivered at between 6-9 mg/day to provide optimal (but not uniform) efficacy at inducing azoospermia. The addition of a single depot dose of a progestin to a suboptimal testosterone dose (6 mg/day) markedly enhances the extent, but not the rate, of spermatogenic suppression, with negligible biochemical androgenic side-effects. These findings provide a basis for the use of a progestin/androgen combination depot for hormonal male contraception.

The effect of levenogesterol (Norplant) contraception on coagulation as measured by antithrombin-III levels

PURPOSE

To determine the effect of contraception given immediately postpartum on coagulation as measured by antithrombin III.

STUDY DESIGN

In this prospective study, parturients (n = 85) self selected three means of postpartum contraception: levenorgesterol implants, oral contraceptives, or a barrier method.

RESULTS

Baseline coagulation was assessed by antithrombin-III levels in each of the 85 women within 48 hours of delivery (100.35 +/- 1.61%) and at one (109.1 +/- 1.89%) and six (105.51 +/- 1.71%) weeks postpartum. There was a rise in antithrombin-III after delivery but there were no significant differences between the groups.

CONCLUSION

The levenorgesterol implant system did not cause a decrease in antithrombin-III in normal parturients.

Bioavailability of orally administered sex steroids used in oral contraception and hormone replacement therapy

The concept of bioavailability is discussed with particular references to the sex steroids. Problems encountered in the measurement of bioavailability of these steroids and the various factors that may affect their bioavailability are briefly described. Information regarding the bioavailability of the estrogens and gestogens, some of which are prodrugs, used in oral contraception and hormone replacement therapy is summarized and the implications regarding the clinical use of these steroids are discussed.

Gestodene-containing contraceptives

As GSD is the most potent progestogen used in oral contraceptives, the doses of GSD can be lower than those of other progestogen components. The monophasic (30 micrograms EE + 75 micrograms GSD) and the triphasic formulation (30 micrograms EE + 50 micrograms GSD/40 micrograms EE + 70 micrograms GSD/30 micrograms EE + 100 micrograms GSD) suppress gonadotropin release and ovarian function profoundly and inhibit ovulation reliably. The strong anti-estrogenic and progestogenic effectiveness of GSD is based on the high GSD serum concentrations achieved during daily intake. Because of the weak androgenic properties of GSD, both formulations can be characterized as estrogen-dominant with respect to their hepatic effects. Except for the first cycles, both formulations afford good cycle control, and the rate of side effects is similar to that with comparable low-dose oral contraceptives. The levels of total and free androgens and androgen precursors, as well as of peripheral androgen activity, are significantly reduced, resulting in a reduced incidence of acne. The concentrations of SHBG and other serum-binding globulins are elevated considerably, and thyroid function is almost unaffected. The estrogen-dominant effect on hepatic metabolism of both formulations also is reflected by a significant increase in the levels of triglycerides and VLDL, HDL, and some apolipoproteins, while LDL-CH and total CH remain unchanged. Similar to other low-dose oral contraceptives, the GSD-containing preparations cause a slight impairment of glucose tolerance that does not appear to be of clinical relevance. However, a significant increase exists in pro-coagulatory and fibrinolytic activity that leads to a considerable stimulation of fibrin turnover. In predisposed women, this may contribute to an elevated risk of venous and arterial thromboembolic diseases.

[Pharmacology of oral contraceptives]

Oral contraceptives include two types of steroids; ethinyl-estradiol as the main estrogenic component which dose vary from 20 to 50 micrograms per tablet (mostly 30 to 35 micrograms) and progestins essentially derivatives of 19 nortestosterone. Derivatives of 19 norprogesterone such as nomegestrol acetate or ST 1435 are not used as oral contraceptives but are being evaluated through parenteral administration, e.g. implants or transdermal systems. The assessment of the pharmacological properties of these progestins indicate a high antigonadotropic and a high antiestrogenic properties for levonorgestrel and for the newer gestagens as well. Therefore very low doses are being used in the current oral contraceptives. However, there is a lower margin of security with the low dose contraceptives than with previous standard combinations and especially when concomitant medications are ingested such as enzyme-inducing agents. Selection of contraceptive methods should be discussed when specific co-medications are necessary.

Immunolocalization of endothelin and neutral endopeptidase in the endometrium of users of subdermally implanted levonorgestrel (Norplant)

Subdermally implanted slow-release levonorgestrel (Norplant), a widely used effective contraceptive, has a high rate of discontinuation due to unacceptable menstrual bleeding disturbances. Endothelin (ET), a potent vasoconstrictor, varies across the menstrual cycle in normal endometrium. It has been proposed that ET has a potential paracrine role in the regulation of uterine blood flow. Neutral endopeptidase (NEP), a membrane-bound ecto-enzyme, can inactivate ET and is localized principally in endometrial stroma. We have compared the immuno-localization of ET and NEP in endometrial biopsies from Indonesian women using Norplant with normal controls. Differences were observed in the glandular and luminal epithelium of Norplant-treated subjects, where ET immunostaining was low while NEP immunoreactivity was increased. The latter may represent a local increase in enzyme activity, potentially explaining the reduced ET immunoreactivity. There was no correlation of ET immuno-reactivity with the duration of implant use or total number of bleeding days. The marked differences in the ET immunostaining pattern in Norplant users, with their increased risk of abnormal uterine bleeding, suggest that ET may be important in controlling menstrual bleeding. Whether endometrial epithelial cell ET has a role as a mitogen in endometrial repair and regeneration, or as a vasoconstrictor important in the cessation of bleeding following menstruation, remains to be determined.

Desogestrel, norgestimate, and gestodene: the newer progestins

OBJECTIVE

To review and compare the newer progestins desogestrel, norgestimate, and gestodene with regard to chemistry, pharmacokinetics, efficacy, and tolerability.

DATA SOURCES

Primary literature on desogestrel, norgestimate, and gestodene was identified from a comprehensive MEDLINE English-literature search from 1984 through 1994, with additional studies selected by review of the references. Indexing terms included progestins, desogestrel, gestodene, norgestimate, levonorgestrel, and norgestrel.

STUDY SELECTION

Only human clinical and pharmacokinetic trials performed in Europe, Canada, and the US were included.

DATA EXTRACTION

All available data from human studies were reviewed; both comparative and noncomparative studies were included because of the paucity of direct comparative information available.

DATA SYNTHESIS

The newer progestins were designed to minimize the adverse effects (e.g., acne, hirsuitism, nausea, carbohydrate and lipid metabolism changes) observed with older oral contraceptives (OCs) while maintaining efficacy and good menstrual cycle control. Desogestrel, norgestimate, and gestodene have minimal amounts of androgenicity and antiestrogenic potential. All of these agents are pharmacokinetically similar to older agents: they are highly bioavailable when administered orally, hepatically metabolized, and obtain steady-state concentrations after 8-10 days of continuous administration. The newer agents have similar Pearl Indexes and slightly better cycle control. Furthermore, the new progestins appear to cause fewer adverse effects, such as acne and hirsuitism, and similar rates of weight gain, blood pressure changes, and lipid and carbohydrate metabolism changes.

CONCLUSIONS

Desogestrel, norgestimate, and gestodene appear to offer clinical advantages because of their decreased androgenicity. Women whose cycles are currently well controlled with other OCs should not be switched to a newer progestin. However, any of the combination OC products that contain these progestins may be prescribed for women intolerant of older agents or to first-time users of OCs. The newer progestins appear to be efficacious and offer similar cycle control, improved safety and tolerability profiles, and comparable price with the older agents.

A comparative study on the return to ovulation following chronic use of once-a-month injectable contraceptives

A comparative study was undertaken involving 21 Mexican women who discontinued the use of medroxyprogesterone acetate 25 mg plus oestradiol cypionate 5 mg (Cyclofem) and norethisterone enanthate 50 mg plus oestradiol valerate 5 mg (Mesigyna) to assess the time required for the return to menses and ovulation. All subjects were exposed to once-a-month injectable contraceptives for two years and were followed for 120 days after the last injection. The urinary concentration of oestrone glucuronide and pregnanediol glucuronide was determined daily in all subjects beginning one month after the last injection. The results disclosed that ovulatory cycles were documented after 120 days of the last injection in six women of each studied group. Similar endometrial bleeding patterns were observed in both groups, indicating that the two drugs have alike pharmacokinetic and pharmacodynamic effects.

Evaluation of body composition during low-dose estrogen oral contraceptives treatment

OBJECTIVE

To determine in a prospective study if the use of two low-dose estrogen oral contraceptives is associated with changes in weight or body composition.

DESIGN

80 outpatients referring to the family planning service, aged 18-43 years were randomly assigned to a treatment with the EE/desogestrel or EE/gestodene association, 20 patients with IUD, aged 26-40 years, were selected as a control group. Anthropometric data and body composition were taken at enrollment and after 6 and 12 months.

MAIN OUTCOME MEASURES

Anthropometric measurements included body mass index (BMI), body composition estimated by mean of Bioelectrical Impendance Analysis (BIA).

RESULTS

In the three groups weight, BMI, and total body water (TBW), and body cellular mass (BCM) remained unchanged during the study period.

CONCLUSIONS

The use of EE/desogestrel and EE/gestodene is not associated with significant variations of body weight and body composition during one year treatment.

Characterization of the novel progestin gestodene by receptor binding studies and transactivation assays

Gestodene is a novel progestin used in oral contraceptives with an increased separation of progestogenic versus androgenic activity and a distinct antimineralocorticoid activity. This specific pharmacological profile of gestodene is defined by its pattern of binding affinities to a variety of steroid hormone receptors. In the present study the affinity of gestodene to the progesterone receptor (PR), the androgen receptor (AR), the glucocorticoid receptor (GR), the mineralocorticoid receptor (MR) and the estrogen receptor (ER) was re-evaluated by steroid binding assays and compared to those obtained for 3-keto-desogestrel and progesterone. The two synthetic progestins displayed identical high affinity to rabbit PR and similar marked binding to rat AR and GR, while progesterone showed high affinity to PR but only low binding to AR and GR. Furthermore, 3-keto-desogestrel exhibited almost no binding to MR, whereas gestodene, similar to progesterone, showed marked affinity to this receptor. In addition to receptor binding studies, transactivation assays were carried out to investigate the effects of gestodene on AR-, GR- and MR-mediated induction of transcription. In contrast to progesterone, which showed antiandrogenic activity, gestodene and 3-keto-desogestrel both exhibited androgenic activity. Furthermore, all three progestins exhibited weak GR-mediated antagonistic activity. In contrast to progesterone, which showed almost no glucocorticoid activity, gestodene and 3-keto-desogestrel showed weak glucocorticoid action. In addition, gestodene inhibited the aldosterone-induced reporter gene transcription, similar to progesterone, whereas unlike progesterone, gestodene did not induce reporter gene transcription. 3-Keto-desogestrel showed neither antimineralocorticoid nor mineralocorticoid action.

An investigation into the effect of tenidap sodium on the pharmacokinetics of a combined oral contraceptive

1. The effects of tenidap sodium and placebo on the pharmacokinetics of a combined oral contraceptive (Microgynon 30) were evaluated in 18 healthy premenopausal women in a double-blind, cross-over study lasting two menstrual cycles. 2. Tenidap (120 mg day-1) or placebo was given for 11 days, starting within 4 days of menstruation and Microgynon 30, containing levonorgestrel (150 micrograms) and ethinyloestradiol (30 micrograms), was administered on day 10 of tenidap therapy. 3. The mean maximum plasma levonorgestrel concentrations (Cmax), time to Cmax (tmax) and area under the plasma time-concentration curves (AUC(0,t)) did not differ between subjects given tenidap or placebo. The Cmax, tmax and AUC(0,t) values for ethinyloestradiol did not differ between tenidap and placebo recipients. Only the ethinyloestradiol Cmax showed a significant difference (P = 0.02) between menstrual cycles 1 and 2 (252.9 pg ml-1 and 271.3 pg ml-1, respectively). 4. Co-administration of tenidap and Microgynon 30 was well tolerated and no subject withdrew from the study because of side-effects. There were no side-effects considered to be related to tenidap and no clinically significant laboratory abnormalities were considered to be related to treatment. 5. The results of the study suggest that the pharmacokinetics of the oestrogen and progestin components of the oral contraceptive Microgynon 30 are unlikely to be affected by concomitant administration of tenidap.

Pharmacokinetics of levonorgestrel and ethinylestradiol in 14 women during three months of treatment with a tri-step combination oral contraceptive: serum protein binding of levonorgestrel and influence of treatment on free and total testosterone levels in the serum

The pharmacokinetics of levonorgestrel (LNG) and ethinylestradiol (EE2) were determined in 14 healthy women (age 18 to 27 years) during a treatment period of three months with a tri-step combination oral contraceptive (Triquilar). Prior to this treatment period, the same women received a single administration of a coated tablet containing 0.125 mg LNG together with 0.03 mg EE2. There was a washout phase of one week between both treatments. Following single dose administration, a mean terminal half-life of 22 h was observed for LNG. The total clearance was 1.0 ml x min-1 x kg-1 and the volume of distribution was 128 l. During a treatment cycle, LNG levels in the serum accumulated by a factor of about four as compared to single dose administration. Steady-state drug levels were reached during the second half of each cycle. As compared to single dose administration, the following changes were observed for LNG at the end of treatment cycles one and three: reduced total (0.5 ml x min-1 x kg-1) and free clearance (50 ml x min-1 x kg-1) and a reduced volume of distribution (52 l). A concomitant increase in the SHBG concentrations by a factor of two as compared to pretreatment values was observed during treatment and appeared to be mainly responsible for the changes in the pharmacokinetics of LNG. Marked changes were also seen for the serum protein binding of LNG. After single dose administration, the free fraction of LNG was 1.4% and the fractions bound to SHBG and albumin were 55.0% and 43.6%, respectively. At the end of cycle one, the free fraction was only 1.0% and the fractions bound to SHBG and albumin were 69.4% and 30.0%, respectively. There was no difference in corresponding pharmacokinetic parameters and in the serum protein binding of LNG at the end of cycles one and three. On the last day of treatment cycles one and three, the AUC(0-4h) values of EE2 were 331.2 and 369.6 pg x ml-1 x h, respectively, which corresponds to an about 11-24% increase as compared to single dose administration, where an AUC(0-4h) value of 298.3 pg x ml-1 x h was found. Total and free testosterone concentrations decreased during treatment cycles one and three by about 41% and 55%, respectively, compared with the corresponding values measured prior to treatment.

The effect of oral contraceptives on protein metabolism

The effect on protein and amino acid metabolism of combined oral contraceptives (OC) containing 150 micrograms of laevonorgestrel and 30 micrograms of ethinyl oestradiol was studied in a group of 34 healthy non-lactating women. This was compared to an identical study conducted in another group of 19 subjects who used IUCDs for contraception, and also in two other groups of subjects who were given an additional multivitamin preparation on a daily basis (29 subjects) and on the days when OC was not taken (29 subjects). Assessments were made prior to, and during the third week of the 4th, 7th, and the 13th cycles of OC treatment. Results indicated that the ceruloplasmin and retinol binding protein underwent significant increases with OC usage, while sex hormone binding globulin concentration, on the other hand, remained unaffected. At the same time, a significant reduction of several of the plasma amino acid and plasma albumin concentrations was observed, suggesting that the increase in the visceral and other types of protein concentrations previously noted was due to increased hepatic protein synthesis rather than increased breakdown or excretion as result of OC intake. Interesting biochemical alterations and metabolic effects previously observed may well be related to this altered synthesis and release of proteins and/or protein binders as well as induction of certain metabolic enzymes from the liver.

Endometrial endothelial cell proliferation in long-term users of subdermal levonorgestrel

The aim of the present study was to quantify endothelial cell proliferation (a component of angiogenesis) using immunohistochemistry, in the endometrium of users of subdermal levonorgestrel (Norplant). It was postulated that the increased endometrial microvascular density seen in Norplant users, compared to normally cycling women, was associated with an increased rate of endothelial cell proliferation. The results, however, showed that the endometrial endothelial cell proliferative index of Norplant users (0.39 +/- 0.16%; mean +/- SEM) was significantly reduced compared to that seen in normally cycling women (8.99 +/- 1.64). At the same time, total numbers of endometrial endothelial cells per mm2 in Norplant users (317.40 +/- 13.88) were significantly higher than in normally cycling women (223.35 +/- 10.31). It is possible that in the endometrium with levonorgestrel use, there is either a reduced rate of regression of the blood vessels relative to the rest of the tissue, or there is a reduced rate of endothelial cell death or turnover. Peripheral oestrogen and progesterone concentrations, bleeding pattern over the previous 90 days, and the histological appearance of the endometrium did not appear to be associated with the endothelial cell proliferative index. The results suggest that subdermal levonorgestrel use affects the mechanisms that dictate the normal relationship between endometrial blood vessel growth and regression, and the surrounding non-vascular tissue.

A two-year clinical study of the effects of two triphasic oral contraceptives on plasma lipids

OBJECTIVE

Oral contraceptive formulations can alter plasma lipid and lipoprotein levels; however, lower-dose triphasic tablets show only minimal metabolic effects during 6 or 12 cycles of use. Involvement of lipids in chronic cardiovascular conditions, plus long-term use of oral contraceptive tablets, prompted this first 24-cycle study of the effect of triphasic formulations on young women.

METHODS

69 women assigned randomly to an ethinyl estradiol/levonorgestrel formulation (Triphasil) or an ethinyl estradiol/norethindrone formulation (Ortho 7/7/7) and 25 control women (no hormonal contraception) had blood sampled for lipids and lipoproteins pre-trial, and at 3- or 6-cycle intervals for 24 cycles.

RESULTS

At cycle 24, control women experienced no significant change from baseline in any variable except apolipoprotein B (apo B). Plasma apo B increased 42% (P < .01), reflecting the LDL apo B increase (42%, P < .01). Both combination formulations significantly increased apo B (plasma, VLDL, IDL and LDL); the increases ranged between 47% and 84%. Plasma apo A1 rose (15%, P < .001) in the Ortho 7/7/7 group only. Plasma and LDL triglycerides were increased significantly (P < .001) by the norethindrone product, 43% and 81%, respectively, and plasma and LDL cholesterol, 14% and 28%, respectively. Cholesterol decreased in all other subfractions, including HDL (11%, P < .01). HDL cholesterol decreased significantly in the Triphasil group (8%, P < .05); no other cholesterol subfractions changed significantly. All cycle-24 lipid and lipoprotein values remained well within respective normal ranges.

CONCLUSION

Although 2-year exposure to the triphasic oral contraceptive formulations changed the lipid risk factors for cardiovascular disease only within normal ranges, there remains potential for long-term health effects when compounded with other risk factors.

Desogestrel versus gestodene in oral contraceptives: influence on the clinical and histomorphological features of benign breast disease

Forty-four female volunteers asking for oral contraception, affected by symptomatic benign breast disease (BBD) were evaluated to compare the effects on mastalgia and breast nodularity of two different low dose oral contraceptives (OCs), containing 20 micrograms [corrected] ethinylestradiol + 150 micrograms desogestrel (EE+D) and 30 micrograms ethinylestradiol + 75 micrograms gestodene (EE+G), respectively. Physical examination, bilateral thermography, X-ray and/or ultrasonography of breast, and needle and screw-needle biopsies of mammary tissue were performed in all patients before OCs administration and after six cycles of treatment. OCs administration caused an overall improvement of mastalgia in 53%. Breast nodularity improved only in 8% of patients in both groups. Epithelial tissue modifications in mammary biopsies were observed, with involutive and/or secretory histomorphological and ultrastructural changes, frequently coexisting in different areas of the same breast.

New knowledge in the physiology of hormonal contraceptives

The present review addresses some of the new knowledge regarding the physiology and mechanisms of action of hormonal contraceptives. Specific topics that are discussed include oral contraceptives, intravaginal rings, long-term contraception, gonadotropin-releasing hormone agonists and antagonists, and antiprogestins. It has been shown that in combined oral contraceptives, lower doses of the new progestins (desogestrel, norgestimate, and gestodene) can be used to inhibit ovulation compared with norethindrone and levonorgestrel. In addition, lower doses of ethinyl estradiol are now used with progestins. Estrogen has been added to intravaginal rings containing levonorgestrel or norethindrone acetate to reduce frequency of bleeding. A new ring containing 3-keto-desogestrel is under evaluation. The use of subdermal implants containing levonorgestrel is currently a popular and highly effective method of long-term contraception. Studies show that gonadotropin-releasing hormone agonists and antagonists can provide ovarian suppression, and antiprogestins such as RU486 effectively block the midcycle gonadotropin surge. These and other novel methods of hormonal contraception are still years away from general use.

Long-acting injectable contraception with depot medroxyprogesterone acetate

Depot medroxyprogesterone acetate (DMPA) is the only injectable contraceptive available in the United States. After more than 20 years of regulatory review, the Food and Drug Administration approved DMPA for contraceptive use in 1992 after the publication of reassuring data about its possible association with breast cancer. It has been used by 30 million women in more than 90 countries. The recommended dosage, 150 mg intramuscularly every 3 months, has a contraceptive efficacy exceeding 99%. After a 150 mg dose, ovulation is inhibited for at least 14 weeks. Almost all users experience menstrual changes, typically episodes of unpredictable irregular spotting and bleeding, particularly during the first year of use. With continued use, spotting and bleeding decrease, and amenorrhea becomes common. Although ovulation suppression may rarely persist for as long as 18 months after the last injection, DMPA does not permanently affect fertility. Long-term DMPA use reduces menstrual blood loss, has been associated with a decreased incidence of candidal vulvovaginitis and pelvic inflammatory disease, and dramatically lowers the risk of endometrial cancer. Prolonged DMPA use may be associated with reversible reduction in bone density, probably related to suppression of endogenous production of estrogen. The most recently published data suggest that long-term use of DMPA induces moderate changes in lipid metabolism that are unfavorable in terms of risk of atherosclerosis. DMPA should be considered a highly effective, safe, convenient, and reversible contraceptive option for appropriately selected patients.

Animal toxicity studies performed for risk assessment of the once-a-month injectable contraceptive Mesigyna

Results from toxicity studies performed for risk assessment of the combined injectable hormonal preparation Mesigyna are reviewed. Both components of Mesigyna, i.e., estradiol valerate (E2Val) and norethisterone enanthate (NET-EN), have been thoroughly investigated as individual compounds and some limited toxicity data have been obtained for the combination. Most findings which were gathered in these studies from different animal species occurred in the gonads, accessory genital and endocrine organs and can be related to the known species-specific pharmacological activity of a typical estrogen or progestin, respectively. No additional or unexpected information which might indicate a possible estrogen/progestin interaction was gained from the administration of the combined preparation to animals. Based on the results from toxicity testing, there were no objections to the long-term therapeutic use of Mesigyna for hormonal contraception. The predictive value of the effects (including the tumorigenicity) observed in the common laboratory animals with regard to human safety is critically discussed, taking the vast amount of previous experience with hormonal contraceptives into consideration. The conclusion is drawn that there is no animal model for safety assessment of sex steroids that adequately represents the human situation. Quantitative extrapolations from animal toxicity findings to humans, therefore, are not possible. Especially, the value of long-term studies and of toxicity studies on estrogen/progestin combinations is put into question. Like endocrine pharmacology studies, the toxicity studies with these steroid hormones are useful for the characterization of the possible endocrine pharmacological profile only.

Pharmacodynamic effects of once-a-month combined injectable contraceptives

The pharmacology and clinical assessment of existing first generation once-a-month combined injectable contraceptives, mainly Deladroxate and Chinese Injectable No. 1, are reviewed. Although these two types of monthly injectables have been used in some million women in China and Latin America, Deladroxate needs indepth re-evaluation of its long-term toxicity and possible accumulation. For injectable No. 1, its disadvantage of being administered on an erratic schedule will cause significant confusion in family planning practice. When used in a strict once-a-month schedule, it is not sufficiently effective for contraception. In order to attain predictable menstrual cycle control as well as high efficacy with a 30-day injection schedule, two improved once-a-month injectable formulations, Cyclofem and Mesigyna, were developed. Pharmacokinetic/pharmacodynamic study on estrogenic components suggested that estradiol valerate and cypionate were suitable estrogen esters to give elevated plasma estrogen levels for 7 to 11 days. After a single injection of Cyclofem and Mesigyna, both formulations showed equal contraceptive effect with inhibition of follicle maturation for some 30 days and ovulation, corpus luteum formation for some 60 days. Multicentre studies on the optimization of dosages of progestogens and estrogens in once-a-month injectables confirmed that the full doses of Cyclofem (DMPA 25 mg/estradiol cypionate 5 mg) and Mesigyna (NET-EN 50 mg/estradiol valerate 5 mg) are suitable for large scale clinical trials. Pharmacodynamics and progestogen/estrogen ratio study indicated the importance of not only the absolute amounts of the progestogen and estrogen but also of their ratio. Reduction of estrogen dose resulted in breakthrough ovulation with both Cyclofem and Mesigyna. Also, it is important to note that the second part of the injection cycle is dominated by the progestogen component of both monthly formulations. A longitudinal study indicated that there is no accumulation of norethisterone after 12 months of treatment with NET-EN 50 mg and estradiol valerate 5 mg.

Pharmacokinetics of a triphasic oral contraceptive containing desogestrel and ethinyl estradiol

OBJECTIVE

To demonstrate that pharmacokinetic measurements were made at steady state. Subsequently, dose proportionality for desogestrel and ethinyl E2 kinetics were demonstrated.

DESIGN

Open-label, noncomparative study.

SETTING

Healthy volunteers in an academic research environment.

PARTICIPANTS

Twenty white women who were 19 to 32 years old were solicited via an advertisement. Nineteen of the 20 women completed the study.

INTERVENTIONS

Study medication consisted of three cycles of a triphasic oral contraceptive containing desogestrel and ethinyl E2. Blood samples were taken at baseline and during cycle 3 between -48 and 24 hours on days 1, 7, 14, and 21, with additional sampling times on day 21 at 48, 60, and 72 hours.

MAIN OUTCOME MEASURES

Serum concentrations of 3-keto-desogestrel and ethinyl E2.

RESULTS

Evaluation of the trough serum levels indicated that a steady state of 3-keto-desogestrel had been reached. Statistical analysis on the Cmax, area under the curve (AUC), and Css,min indicated dose proportionality for the administered desogestrel. Ethinyl E2 serum levels obtained at the same time points also reflected steady state levels and showed minimal variability. The statistical analysis on Cmax, AUC, Css,min, and Tmax indicated that the pharmacokinetics of ethinyl E2 on days 7, 14, and 21 were not statistically significantly different, indicating dose equivalency.

CONCLUSIONS

Steady state of 3-keto-desogestrel is reached after each of the three phases and the pharmacokinetics are dose proportional. After reaching steady state, the pharmacokinetics of ethinyl E2 remain constant over time.

Pharmacokinetics of once-a-month injectable contraceptives

The addition of a short- or medium-acting estrogen ester to the long-acting progestins depot-medroxyprogesterone acetate (DMPA) and norethisterone enanthate (NET-EN) to produce "combined" injectable formulations has proved a successful strategy in the development of once-a-month injectable contraceptives. Recent clinical pharmacokinetic studies undertaken on once-a-month injectable contraceptives in various WHO Collaborating Centers have guided the selection of the estrogen-progestogen combinations, ratios and dose schedules. At least three combined once-a-month injectable preparations exhibit acceptable pharmacokinetic and pharmacodynamic profiles; however, further improvement in the design of optimal estrogen/progestin injectables are expected during this decade.

Comparative assessment of the effects of subdermal levonorgestrel implant system and long acting progestogen injection method on lipid metabolism

In order to compare the effects of two type of long-acting progestogen contraceptive methods with subdermal levonorgestrel (LNG) implants and depot-medroxyprogesterone acetate (DMPA) injections on lipid metabolism, a clinical cohort study was performed by requiring 25 women in each group adopting either LNG implant or DMPA injection method voluntarily. After 6 months of use, serum levels of triglycerides, total cholesterol, HDL-cholesterol and LDL-cholesterol were determined and compared between the two groups of acceptors. The mean of total cholesterol in LNG implant acceptors was significantly lower than that in DMPA injection acceptors. The mean values of HDL-cholesterol in LNG implant acceptors (41.7 +/- 7.7 mg/dl) and in DMPA injection acceptors (45.0 +/- 9.0 mg/dl) were in the normal range without significant difference between the two groups. The mean value of triglycerides did not differ significantly between LNG implant acceptors (77.6 +/- 25.1 mg/dl) and DMPA injection acceptors (91.0 +/- 30.3 mg/dl). Serum concentrations of lipid fractions such as HDL-cholesterol and LDL-cholesterol in LNG implant acceptors were relatively low compared to those in DMPA injection acceptors. Since there was a comparable reduction in both total-and HDL-cholesterol levels in the LNG implant group, the ratio of total-to HDL-cholesterol, which is thought to be a factor in determining the risk of coronary artery disease, remained in the normal range (2 +/- 4.5). This suggests that the use of these two contraceptive methods with progestogens does not alter the risk of development of coronary artery disease.

New progestogens in oral contraception

The major developments in combined oral contraceptives (COCs) have been a reduction in the total dose of both the oestrogen and progestogen administered per cycle and the introduction of new progestogens which are claimed to be more 'selective' than the older ones. This review examines in detail the clinical efficacy of the new COCs, where possible in comparison with those containing levonorgestrel or norethisterone, and their pharmacological effect on carbohydrate and lipid metabolism, haematological factors, pituitary-ovarian function and serum protein and androgen concentrations. Based mainly on the pharmacological evidence, the newer COCs are an improvement over the older low-dose formulations and are clearly preferable to the high-dose ones. However, the older low-dose COCs, despite many years of use, have not resulted in a high incidence of adverse effects. The increasing use of the new COCs, as evidenced by their increasing market share throughout Europe, does indicate that they have been well accepted in clinical practice.

A comparative metabolic study of two low-estrogen-dose oral contraceptives containing desogestrel or gestodene progestins

OBJECTIVES

Our objective was to compare the effects of low-estrogen-dose oral contraceptives containing desogestrel or gestodene progestins on metabolic risk markers for coronary heart disease.

STUDY DESIGN

A cross-sectional comparison of 70 women who used a formulation that contained 30 micrograms ethinyl estradiol and 150 micrograms desogestrel, 43 women who used a formulation that contained 30 micrograms ethinyl estradiol and 75 micrograms gestodene, and 54 women who did not use steroidal contraceptives was performed.

RESULTS

Oral contraceptive users had higher concentrations of high-density lipoproteins than did women in the control group (+10% to +20%, p < 0.001) primarily because of increases in high-density lipoprotein subfraction 3. High-density lipoprotein subfraction 2 concentrations were higher in users of the desogestrel formulation. Low-density lipoprotein cholesterol concentrations were normal in oral contraceptive users, but triglyceride concentrations were high (+80% to +100%, p < 0.001). Fasting glucose, insulin, and C-peptide concentrations were similar in the three groups, but their responses to a glucose load were higher in oral contraceptive users than in controls (p < 0.01 to p < 0.001). The late plasma insulin response to glucose was higher in the women who used the gestodene formulation than in those who used the desogestrel formulation.

CONCLUSIONS

The metabolic profiles induced by these oral contraceptives were remarkably similar and may reflect the activity of the estrogen component.

Pharmacokinetics of gestodene and ethinylestradiol in 14 women during three months of treatment with a new tri-step combination oral contraceptive: serum protein binding of gestodene and influence of treatment on free and total testosterone levels in the serum

The pharmacokinetics of gestodene (GEST) and ethinylestradiol (EE2) were determined in 14 healthy women (age 18 to 32 years) during a treatment period of three months with a new tri-step combination oral contraceptive (Milvane). Prior to this treatment period, the same women received a single administration of a coated tablet containing 0.1 mg GEST together with 0.03 mg EE2. There was a wash-out phase of one week between both treatments. Following single dose administration, a mean terminal half-life of 18 h was observed for GEST. The total clearance was 0.9 ml x min-1 x kg-1 and the volume of distribution was 84 l. During a treatment cycle, GEST levels in the serum accumulated by a factor of 8 as compared to single dose administration. Steady-state drug levels were reached during the second half of each cycle. As compared to single dose administration, the following changes were observed for GEST at the end of treatment cycles one and three: prolonged terminal half-life (20 to 22 h), reduced total (0.16 ml x min-1 x kg-1) and free clearance (ca. 27 ml x min-1 x kg-1), reduced volume of distribution (ca. 18 l). A concomitant EE2-induced increase in the SHBG concentrations by a factor of three as compared to pretreatment values was observed during a treatment cycle and appeared to be mainly responsible for the changes in the pharmacokinetics of GEST. Marked changes were also seen for the serum protein binding of GEST. After single dose administration, the free fraction of GEST was 1.3% and the fractions bound to SHBG and albumin were 69.4% and 29.3%, respectively. At the end of cycle one, the free fraction was only 0.6% and the fractions bound to SHBG and albumin were 81.4% and 18.0%, respectively. There was no difference in corresponding pharmacokinetic parameters and in the serum protein binding of GEST at the end of cycles one and three. On the last day of treatment cycles one and three, the AUC(0-4h) values of EE2 were 299.2 and 278.1 pg x ml-1 x h, respectively, which corresponds to an about 30% increase as compared to single dose administration, where an AUC(0-4h) value of 216.1 pg x ml-1 x h was found. Total and free testosterone concentrations decreased during treatment cycles one and three by about 36% and 60%, respectively, compared with the corresponding values measured prior to treatment. The fraction of unbound testosterone thus decreased from 0.5% to 0.3% during treatment.

Ovulation inhibition with a combined oral contraceptive containing 1 mg micronized 17 beta-estradiol

OBJECTIVE

To evaluate ovarian function by ultrasonography and endocrine measurements.

DESIGN

Prospective, open study.

SETTING

Outpatient clinic of the First Department of Gynaecology and Obstetrics, University of Vienna, Austria.

PARTICIPANTS

Twenty healthy women with regular cycles and established ovulation by ultrasonography.

INTERVENTION

Treatment with a combination of 1 mg micronized E2 with 150 micrograms desogestrel daily for 21 days, followed by 7 pill-free days.

MAIN OUTCOME MEASURES

Transvaginal ultrasonography and estimation of E2 and P at least twice a week for two consecutive cycles, followed by one after treatment cycle.

RESULTS

Ovulation inhibition was apparent in all cases and no functional ovarian cysts were observed during treatment. On a few occasions a persistent follicle was noted, but in the majority of cases there was total absence of follicular activity. The bleeding pattern showed a tendency toward prolonged and more heavy bleeding when compared with the before treatment situation. Return of ovulation was prompt in all women but one.

CONCLUSIONS

Ultrasonographic observations, accompanied by P and E2 measurements, allow us to conclude that the combination of 1 mg E2 with 150 micrograms desogestrel provides complete ovulation inhibition. However, the bleeding pattern does not show an acceptable profile.

Sequential regimen of the antiprogesterone RU486 and synthetic progestin for contraception

OBJECTIVE

To examine the effect of sequential use of the antiprogesterone RU486 and synthetic progestin on ovarian function of healthy women.

DESIGN

Healthy women were given a sequential antiprogesterone-progestin treatment. Blood samples were taken twice a week during one control cycle and one to three treatment cycles; prospective analysis.

SETTING

The outpatient clinic of the Helsinki City Maternity Hospital, Helsinki, Finland, and Steroid Research Laboratory, Department of Medical Chemistry, University of Helsinki, Helsinki, Finland.

PATIENTS

Eleven healthy women, volunteers, 20 to 34 years of age.

INTERVENTIONS

A dose of 25 mg/d of RU486 was given during cycle days 1 to 21, and synthetic progestin (5 mg of norethisterone to six and 5 mg of medroxyprogesterone acetate to five women) during cycle days 22 to 31.

MAIN OUTCOME MEASURES

Serum P, E2, FSH, and LH were measured from serum samples.

RESULTS

In 20 of the 24 treatment cycles analyzed the serum concentrations of P were anovulatory. In the remaining 4 cycles, P levels rose above 3 ng/mL, suggestive of ovulation. Folliculogenesis was not completely inhibited, but serum E2 profiles were subnormal and delayed. Bleeding control was satisfactory.

CONCLUSIONS

Antiprogesterone RU486 hampers or delays follicular development, suggesting a possible use as an estrogen-free oral contraceptive. However, the synthetic progestins used in this regimen induced serum P rises in some cycles. The synthetic progestin provides the cycle control, but its possible effect on the reliability of the method remains to be evaluated.

Effects of different doses of norethisterone on ovarian function, serum sex hormone binding globulin and high density lipoprotein-cholesterol

The ovarian effects of different doses of norethisterone (NET) were compared in 45 normally menstruating women in order to find the lowest effective dose of the Chinese NET "visiting pill". Subjects were randomly divided into 3 groups. Each subject in each group was taking 0.5, 1.5 or 3.0 mg per day from days 5 to day 18 of the cycle. Blood samples were taken on days 5, 8, 11, 14, 17, 20, 23, 26 and 29 of the cycle. Serum oestradiol (E2), progesterone (P), sex hormone binding globulin (SHBG), high density-lipoprotein cholesterol (HDL-C), and NET concentrations were measured. Ovulation, delayed ovulation, ovulation inhibition and follicular activity were classified by the analysis of the peripheral serum levels of sex hormones. Ovulation occurred in 7 women in the 0.5 mg group, in 2 women in the 1.5 mg group and in none of the 3.0 mg group. Mean serum SHBG levels were reduced progressively by 6.6% (Group 0.5), 15.5% (Group 1.5) and 23.4% (Group 3.0). There were no significant changes in HDL-C levels in any group. There was a significant correlation of mean serum NET concentrations with dose. The lack of complete inhibition of ovulation in most women in the 1.5 mg and 0.5 mg groups might suggest that the dose of NET required when used as a visiting pill could not be reduced below 3.0 mg.

Single- and multiple-dose pharmacokinetics of a low-dose oral contraceptive in women with chronic renal failure undergoing peritoneal dialysis

OBJECTIVE

Our purpose was to compare the pharmacokinetic parameters of oral administration of a 35 micrograms ethinyl estradiol, 1 mg norethindrone pill in peritoneal dialysis patients and normal women.

STUDY DESIGN

A single-dose study was performed with five patients and four controls, followed by a multiple-dose study with five subjects in each group. Pharmacokinetic parameters were calculated by noncompartmental analysis and statistical analysis performed with Mann-Whitney U testing.

RESULTS

There is no difference in the pharmacokinetic parameters for norethindrone in peritoneal dialysis patients compared with normal women. During multiple dosing an increased area under the concentration curve and decreased apparent oral clearance was observed for ethinyl estradiol in peritoneal dialysis patients compared with normal women.

CONCLUSION

Peritoneal dialysis patients have decreased apparent oral clearance of ethinyl estradiol, leading to slightly higher serum concentrations compared with women with normal renal function. The clearance of norethindrone is the same in peritoneal dialysis patients and normal women.

Pharmacokinetics of desogestrel

A synthetic form of desogestrel, a gonane progestin, was developed because desogestrel's enhanced selectivity eliminates adverse, androgen-dependent, metabolic effects at contraceptive doses. Desogestrel is rapidly and completely metabolized in the liver and gut wall to 3-keto-desogestrel, which is the active metabolite mediating the progestin effects. Because of its unique 11-methylene side chain, desogestrel cannot be metabolized to any other known progestin, nor is desogestrel a naturally occurring metabolite of any other progestin. The pharmacokinetic parameters of 3-keto-desogestrel are generally comparable with those of levonorgestrel and norethindrone. Therefore any differences in pharmacologic activities must be attributed to differences in intrinsic activities. Unlike gestodene, 3-keto-desogestrel has a lower affinity for sex hormone-binding globulin, which results in markedly lower plasma levels after administration. After oral administration of 150 micrograms of desogestrel, plasma levels are less than half the levels of gestodene after an oral dose of 75 micrograms.

Preclinical evaluation of norgestimate, a progestin with minimal androgenic activity

Norgestimate is a novel progestin with highly selective progestational activity and minimal androgenicity. In rabbits, norgestimate binds to uterine progestin receptors, stimulates the endometrium, and inhibits ovulation. Norgestimate acts directly on target organs, stimulating rabbit endometrium when injected into the uterine cavity and inhibiting luteinizing hormone-releasing hormone-stimulated luteinizing hormone release in dispersed rat pituitary cells in culture. Norgestimate has no estrogenic activity, and like other progestins, it suppresses the action of estrogen. Unlike some other progestins, it is relatively free of androgenic activity. Norgestimate and its 17-deacetylated metabolite demonstrate very poor affinity for androgen receptors compared with levonorgestrel and gestodene and do not exhibit androgenic activity when measured as the stimulation of prostatic growth in immature rats. Norgestimate's lack of affinity for human sex hormone-binding globulin is further evidence of its minimal androgenicity.

Pharmacokinetics and protein binding of gestodene under treatment with a low-dose combination oral contraceptive for three months

The serum concentrations of gestodene (CAS 60282-87-3) as well as the binding of this progestin to serum proteins were studied in 40 women who took a low-dose oral contraceptive (Femovan, Femodene) containing 30 micrograms ethinyl estradiol (CAS 57-63-6) and 75 micrograms gestodene for 3 months. On days 1, 10, and 21 of the first and the third treatment cycle, respectively, 7 blood samples were drawn before and up to 4 h after pill intake; additional samples were taken prior to morning ingestion of pill on days 2, 5, 11, 15 and 22 of these cycles. Gestodene levels were measured by means of a specific radioimmunoassay and were evaluated for Cmax, tmax, and AUC up to 4 and 24 h. Independent of the test day and the treatment cycle studied, mean maximum gestodene serum levels were found about 0.8 to 0.9 h after pill intake. During the first treatment cycle, mean values of Cmax, AUC(0-4h), and AUC(0-24h) amounted to 4.3 ng.ml-1, 9.3 ng.ml-1.h, and 27.3 ng.ml-1.h on test day 1; these values increased by 250-400% and by 300-500%, respectively, when days 10 and 21 were compared to day 1. On day 1 of the third treatment cycle, these pharmacokinetic parameters were higher by almost a factor of two as compared to the corresponding data obtained on the beginning of the first cycle whereas the increase of these values between day 1 and the subsequent test days (200-300%) was slightly lower in cycle 3 as compared to cycle 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics and serum protein binding of gestodene and 3-keto-desogestrel in women after single oral administration of two different contraceptive formulations

Two low-dose oral contraceptives, both containing the same dose of ethinyl estradiol (EE2, CAS 57-63-6) but different progestins--gestodene (CAS 60282-87-3) and desogestrel (CAS 54024-22-5), respectively--were administered to 18 women in a single dose, cross-over study. The serum concentrations of gestodene (GEST, one of the components of Femovan) and 3-keto-desogestrel (KDG) have been measured by specific radioimmuno-assays and the pharmacokinetics of both progestins were assessed. The serum protein binding of both compounds was also investigated and although the free fraction was the same for GEST and KDG, the distribution with respect to the binding proteins albumin and sex hormone binding globulin (SHBG) was slightly different. GEST was mainly bound to SHBG, while KDG was predominantly bound to albumin. Maximum concentrations of GEST were observed after 0.7 +/- 0.2 h and amounted to 4.9 +/- 2.4 ng/ml. A biphasic pattern of disposition was observed, with half lives of 0.13 +/- 0.06 h and 14.6 +/- 4.2 h, respectively. The AUC was 32.9 +/- 18.3 ng.ml-1.h. For KDG, maximum serum levels of 1.7 +/- 0.8 ng/ml were observed 1.5 +/- 0.8 h post administration. Drug levels declined with half-lives of 0.5 +/- 0.2 h and 17.0 +/- 9.3 h, respectively, and the AUC was 15.2 +/- 10.9 ng.ml-1.h.

Pharmacokinetics and serum protein binding of 3-keto-desogestrel in women during three cycles of treatment with a low-dose combination oral contraceptive

The serum concentrations of 3-keto-desogestrel have been measured in 43 women who took a low-dose oral contraceptive containing 30 micrograms ethinyl estradiol (CAS 57-63-6) together with 150 micrograms desogestrel (CAS 54024-22-5) for a period of 3 months. Basic pharmacokinetic parameters, like Cmax, tmax and AUC, as well as the serum protein binding of 3-keto-desogestrel were determined on days 1, 10 and 21 of the first and the third treatment cycle, respectively. During cycle one, Cmax, AUC(0-4h) and AUC(0-24h) values on day 1 were 1.9 +/- 0.7 ng/ml, 3.9 +/- 1.3 ng.ml-1.h and 12.4 +/- 5.7 ng.ml-1.h, respectively. These values increased to 4.7 +/- 2.0 ng/ml, 12.1 +/- 5.6 ng.ml-1.h and 47.3 +/- 26.0 ng.ml-1.h on day 21. Within cycle 3, a similar, although less steep increase was observed for these parameters and there was practically no difference in the values of corresponding parameters on day 21 of both cycles. Throughout treatment, there was a redistribution of 3-keto-desogestrel with respect to the binding proteins albumin and sex hormone binding globulin (SHBG). During cycle 1, the free fraction decreased from 1.8% on day 1 to 1.1% on day 21, and the SHBG-bound fraction increased at the same time from 40% to 62%, mainly at the expense of the albumin-bound fraction. During cycle 3, there were only minor changes as compared to cycle one. The observed changes in the serum protein binding were related to an increase in SHBG levels during the treatment period.

Pharmacokinetics of gestodene in 12 women who received a single oral dose of 0.075 mg gestodene and, after a wash-out phase, the same dose during one treatment cycle

The pharmacokinetics of gestodene (GEST) was determined in 12 healthy women (age 22 to 34 years), following single dose administration of 0.075 mg GEST. The same preparation was also administered during one treatment cycle after a wash-out phase of 1 week. After single dose administration, maximum concentrations of GEST in the serum were 4.9 +/- 2.5 ng/ml. Post maximum drug levels declined biphasically with half-lives of 0.2 +/- 0.2 h and 14.9 +/- 6.7 h, respectively. The apparent clearance was calculated to be 0.8 +/- 0.4 ml x min-1 x kg-1. The free fraction of GEST was 1.3 +/- 0.3% and the fractions bound to SHBG and albumin were 64.3 +/- 10.7% and 34.4 +/- 10.4%, respectively. The results showed that there was a gradual decrease in serum trough levels of GEST during the cycle, due to a concomitant and equally high decrease in SHBG concentrations in the serum of about 26%. At the end of one treatment cycle, the free fraction of GEST increased to 1.8 +/- 0.5%, the SHBG-bound fraction decreased to 57.0 +/- 10.2% and the albumin-bound fraction increased to 41.3 +/- 9.9%. Total serum clearance increased during the same time period from a mean value of 0.8 to about 1.2 ml x min-1 x kg-1. The clearance of unbound GEST, however, remained unchanged. An examination of the free GEST concentrations revealed the same time course of GEST 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 GEST 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 GEST. There was no evidence of GEST inhibiting its own metabolism.

Progestins and breast cancer: an epidemiologic review

OBJECTIVE

To provide a worldwide review of all studies that have examined the relationship between progestins, as contained in both contraceptive and postmenopausal replacement therapies, and breast cancer risk. An overview of utilization patterns for progestins, as well as a review of possible biological mechanisms for progestins' action on breast tissue, are also presented.

DATA IDENTIFICATION

All major epidemiologic studies conducted since 1980 have been identified through MEDLINE searches through the published literature and personal communications with prominent researchers in the area.

STUDY SELECTION

Only studies that specifically examined the effects of progestin use are discussed here; these include investigations of progestins, in combination or singularly, as the main hypothesis or a subgroup analysis.

RESULTS

The majority of studies have examined combination estrogen and progestin products (oral contraceptives), and subgroup analyses of progestins have been impeded by low statistical power and the fact that each progestin possesses different types of pharmacological activity. Only a few studies of long-acting injectable progestins exist, confirming a general lack of specific information on the progesterone-breast cancer relationship. Investigations of the effect on breast cancer of the addition of progestins to postmenopausal replacement therapy have also produced inconsistent results.

CONCLUSIONS

To date, there is no consistent evidence of an association between progestins and breast cancer. There is need for further study, particularly of patients in potentially high-risk groups, including those with (1) extended hormone exposure before age 25 and/or first full term pregnancy and (2) exposure in the postmenopausal period.

Effect of Norplant implants on liver, lipid and carbohydrate metabolism

In this study involving 100 women, the metabolic changes seen with Norplant use were evaluated. Besides a significant increase in serum bilirubin, there were no other changes in liver function to suggest possible hepatocellular dysfunction at the end of five years. Even the raised mean levels of bilirubin remained within the normal clinical range for the local population. As regards lipid metabolism, total triglycerides, cholesterol and LDL-cholesterol were decreased through the five years of Norplant use. The HDL-cholesterol showed a significant increase in the first year; it then decreased over the years to its preinsertion level at the end of five years. As a result, the HDL-cholesterol/Total cholesterol - HDL-cholesterol showed a significant increase in the first year and then decreased to almost its preinsertion value at the end of five years. The findings appear to indicate Norplant use not to be contributory to cardiovascular risk. The use of Norplant was not associated with any significant effect on carbohydrate metabolism.

Concentration of fat, protein, lactose and energy in milk of mothers using hormonal contraceptives

Energy, protein, lactose and fat were studied in the milk of mothers who were using different types of contraceptives. One hundred and eleven mothers made up the following groups. C: control (barrier and natural methods, or sterilization), n = 22; combined pill: LDP (low dose pill (levonorgestrel 0.15 mg + ethinylestradiol 0.03 mg)), n = 12 and MDP (medium dose pill (levonorgestrel 0.25 mg + ethinylestradiol 0.05 mg)), n = 13; MP (minipill (norethindrone 0.35 mg)), n = 37; DMPA (injectable progesterone (depot medroxiprogesterone acetate 150 mg)), n = 17; and IUD (plastic or copper intrauterine device), n = 10. The mean stages of lactation were, respectively, 15, 17, 5, 9, 5 and 9 weeks. The mean duration of observation for the study groups ranged from 2 to 4 weeks. Milk samples were collected before and after initiation of treatment (mean = 20 days; range = 14-103 days). The stage of lactation and the interval of nursing before sampling were recorded so that statistical account could be taken of these uncontrollable sources of variability. When incorporated as covariates, they showed that no significant differences existed between the groups tested, either before or after treatment.

Subdermal progestin implant contraception

Sustained-release progestin contraceptives are a new approach to meeting a worldwide need for more effective and acceptable birth control. These contraceptive systems provide low, stable levels of synthetic progestins for periods of months to several years. Unlike earlier injectable and oral contraceptives, they do not cause peaks in progestin levels beyond those required for effective contraception, nor do they employ estrogens. For these reasons, sustained-release progestin systems are without some of the health risks attributed to birth control pills, and they are more effective, as well as easy to use, and completely reversible. They share common side effects, the most frequent of which is irregular menstrual bleeding caused by the erratic shedding of hypotrophic endometrium. Despite this and other minor side effects, most users find the sustained-release systems acceptable alternatives to other methods of contraception. Permanent or biodegradable subdermal implants, injections, intrauterine and intracervical devices, and vaginal rings are all employed as delivery systems for contraceptive progestins. The Norplant (Wyeth Ayerst, Radnor, PA) system, consisting of six silastic tubes filled with levonorgestrel and implanted under the skin, was recently approved by the US Food and Drug Administration and is already used by more than a half million women worldwide. The other sustained-release systems are in various stages of development, at least several years away from general use. When these new methods complete clinical trials, women will be able to choose from among implants, injections, or pellets with various durations of action, all providing convenient, highly effective contraception with low risk to health.

Characteristics of the new progestogens in combination oral contraceptives

This review details the characteristic features of three new progestogens which soon will be available in low-dose combination oral contraceptive agents in the United States. Available data suggest that desogestrel, gestodene, and norgestimate are extremely potent progestogens with few androgenic side effects. The smaller changes in lipids induced by these progestogens seem to confer some advantage to the use of preparations containing one of these agents. Whether this advantage is also present clinically remains to be determined.

Biology of female sex hormone action in relation to contraceptive agents and neoplasia

This article will present an overview of estrogen and progestin action at a cellular level, with emphasis on points that are relevant to neoplasia. In breast, endometrium and ovary, these two classes of hormone are clearly implicated in carcinogenesis, but their involvement with cancers of the liver, cervix and other tissues is more problematic. In the latter situations, I will highlight the major points to be considered if the hormones are involved without wishing to judge whether there actually is a causal involvement.

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.

A neutrophilic reaction of Sweet's syndrome type associated with the oral contraceptive

A case is presented of a Sweet's syndrome-like eruption in association with the oral contraceptive. A 46 year old caucasian woman developed recurrent episodes of erythematous tender plaques on her trunk six weeks after commencement of the oral contraceptive (OC). Her condition clinically and histologically resembled Sweet's dermatosis. On cessation of the OC there was complete resolution of her lesions and she remains well 12 months later. This is the first report, to our knowledge, of a neutrophilic reaction to the oral contraceptive, and we believe that drugs may be implicated in the aetiology of atypical neutrophilic reactions simulating Sweet's syndrome in patients who are otherwise well.