A method for the estimation of 6-oxygenated metabolites of progesterone in urine

1. A method is described for the estimation of the 6-oxygenated metabolites of progesterone in urine. After hydrolysis the extract of urine is chromatographed on alumina to obtain a fraction containing mainly the 6-oxygenated metabolites. This fraction is oxidized to convert the metabolites into pregnane-3,6,20-triones, which are estimated as the dinitrophenylhydrazones. 2. The reliability criteria of the method are presented. Normal subjects excrete 0.1-0.6mg./day, and at the end of pregnancy values of 3.3-11.6mg./day are obtained.

Metabolic interrelationships, cardiovascular disease, and sex steroids

Future studies of the pharmacodynamics of oral contraceptives should encompass interactions between various areas of physiology rather than concentrate on single metabolic processes. Changes in one area of metabolism may affect other areas. Insulin plays a central role in metabolic control and, in addition to profound effects on carbohydrate and lipid metabolism, also affects the hematological system. Insulin has been proposed as a major physiological regulator of plasminogen activator inhibitor, and hyperinsulinemia is associated with increased blood coagulability and decreased fibrinoloysis. There is a close relationship between insulin and triglyceride metabolism, and this may affect factor VII activity in blood. There are many interactions between lipid metabolism and hematological factors. The apoprotein of lipoprotein (a) is structurally similar to plasminogen. Tissue factor pathway inhibitor, a regulator of coagulation, circulates in blood bound to LDL and HDL. Some fatty acids may act as a contact surface for activation of hematological factors. Dietary factors also need to be considered. Changes not only in the quantity but also in the composition of dietary fat influence lipid metabolism and also blood levels of a number of hematological factors. Other aspects of pharmacodynamic studies that require consideration and other factors that affect metabolic interrelationships are discussed.

Can a change in screening and prescribing practice reduce the risk of venous thromboembolism in women taking the combined oral contraceptive pill?

The risk of Venous thromboembolism (VTE) associated with low dose combined oral contraceptive pills (COCs) is low at between 15 and 30 cases per 100 000 women years of use. Screening the total population or even those women with a family history of VTE in a first degree relative is unlikely to have a major impact on the number of cases of VTE associated with COC. Women with a known family history of an inherited thrombophilia should have this defect excluded before taking COCs. Women with a known thrombophilia or a personal history of VTE should consider alternative methods of contraception to the COC.

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.

Enlarged follicles in women using oral contraceptives

Ultrasound examination of the ovaries was performed in the first and/or second half of three consecutive cycles in 3 groups of women; Group T who had been using a levonorgestrel triphasic oral contraceptive for at least 6 months, Group P who had been using a progestogen-only pill for at least 6 months, and Group C, a control group. Any follicles greater than 10 mm in diameter and any cysts were measured. Fifty-three scans were performed in Group T, 45 in Group P and 31 in Group C. Only 4 follicles were detected in 17 women in Group T compared to 10 follicles in 15 women in Group P and 7 follicles in the women in Group C; all follicles were 25 mm or less in diameter except for 3 follicles in 2 women. The differences between the groups were not statistically significant. Four enlarged follicles were detected in 3 women during 53 scans in Group T, 15 in 8 women (45 scans) in Group P, and only 1 in 31 scans in Group C. Based upon the proportions of scans with enlarged follicles, the difference between Groups T and P was statistically significant, indicating that the incidence of enlarged follicles was lower in women using a combined oral contraceptive than in those using a progestogen-only pill. Furthermore, the study shows that any enlarged follicles which occurred were transient.

Levonorgestrel. Clinical pharmacokinetics

Published values for the serum concentrations and pharmacokinetic parameters of levonorgestrel after administration of various doses of levonorgestrel alone or with ethinylestradiol are reviewed. Most data apply to oral administration of the gestagen, with the smaller amount of data for other modes of administration, e.g. subcutaneous, intravaginal and intra-uterine administration, also included. There is a large variability among the different studies for both serum concentration and pharmacokinetic parameters and not all of this is due to the large interindividual variability demonstrated in all of the studies. The factors responsible for the inter- and intraindividual variability have not been discovered. Sex hormone binding globulin (SHBG) plays an important role in levonorgestrel pharmacokinetics since: (i) levonorgestrel binds strongly to this protein; and (ii) serum SHBG levels are influenced by a large number of different factors including the administration of levonorgestrel and ethinylestradiol. However, not all of the anomalies in the metabolism of levonorgestrel can be ascribed to its interaction with SHBG.

Twelve years of clinical experience with an oral contraceptive containing 30 micrograms ethinyloestradiol and 150 micrograms desogestrel

The clinical experience with a combined oral contraceptive (COC) containing 150 micrograms desogestrel and 30 micrograms ethinylestradiol is reviewed. Fourteen clinical trials have been reported involving over 44,000 women for more than 190,000 cycles. None of the 17 pregnancies which occurred (overall Pearl Index 0.12) were due to method failure. The incidences of breakthrough bleeding and spotting after 6 treatment cycles varied from 0.1-6.0% and 2.8-11% of subjects, respectively, and at this time they were not significantly different from pretreatment in most trials. About 90% of subjects maintained regular cycles. The incidence of subjective side effects (approximately 5% for headache, 4% for breast tenderness, 2% for nausea) was low. No significant changes occurred in body weight or blood pressure. In all trials, the COC was well accepted and the rates of discontinuation were similar to those in other COC trials. Pharmacodynamic effects have been widely investigated. There were no significant changes in glucose metabolism or in haematological factors except for possibly minor increases in factors VII and X, fibrinogen and plasminogen. Over thirty studies of the effect of the COC on lipid metabolism have been published; significant increases occur in serum triglycerides, HDL-C and apoprotein A1. SHBG concentrations increase 2-3 fold with a consequent decrease in the levels of free testosterone. This effect can be particularly important therapeutically in women with hyperandrogenic skin disorders and 14 trials in women with these disorders have demonstrated significant clinical improvement with the COC. The findings from the various trials show the COC to be effective and acceptable with no adverse metabolic effects.

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.

Pharmacokinetic study of RU 486 and its metabolites after oral administration of single doses to pregnant and non-pregnant women

RU 486 and three of its metabolites (RU 42633-monodemethyl, RU 42848-didemethyl, and RU 42698-hydroxymetabolite) were determined by HPLC in plasma from nine non-pregnant and 36 pregnant women. Each non-pregnant subject took an oral dose of RU 486 (25, 100, 400 and 600 mg consecutively) once per menstrual cycle. Six of the nine women also received a dose of 200 mg. The 36 pregnant women were randomized into four groups which were given a single dose of 25, 100, 400 or 600 mg RU 486. Blood samples were taken up to 120 h after dosing. Peak concentrations of RU 486 occurred on most occasions within 2 h. Plasma concentrations at 1 h and at 24 h increased in proportion to log dose. There was a wide variability (up to ten-fold) in the pharmacokinetic parameters within each dose group. Plasma concentrations of RU 42633 were similar to those of RU 486 but concentrations of RU 42848 and RU 42698 were much lower. As with RU 486, the plasma concentrations of the metabolites were maintained at high levels for up to 48-72 h after dosing. The findings were consistent with a rapid metabolism of RU 486 to RU 42633; removal of the second methyl group leading to RU 42698 occurred much more slowly and to a much less extent than removal of the first. There appeared to be no significant differences between the non-pregnant and pregnant women in either the plasma concentrations or pharmacokinetic parameters of RU 486 and its metabolites.

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.

Clinical experience and pharmacological effects of an oral contraceptive containing 20 micrograms oestrogen

The performance of a new low-dose oral contraceptive (Mercilon) containing only 20 micrograms ethinyloestradiol combined with 150 micrograms desogestrel is reviewed. Eight multicentre clinical trials have been completed and provide information on 10,672 women studied over 73,477 cycles. The high efficacy of Mercilon was indicated by the finding that only 10 pregnancies were reported; nine of these occurred in women who omitted to take Mercilon on a number of days and only one in a woman who took all the tablets according to instructions. Cycle control was good; as with all oral contraceptives, the incidence of breakthrough bleeding and spotting was highest in the first treatment cycle and by the sixth treatment cycle the values were usually < 5% and < 7%. More than 80% of women had regular cycles. Side effects were few, the most common being headache, nausea and breast tenderness with incidences in the sixth treatment cycle of less than 2%, 6% and 6%, respectively. There were no significant changes in body weight or blood pressure. Pharmacodynamic investigations showed no adverse effects. Only 1 of 5 studies found an increased response to a glucose tolerance test compared to the pretreatment test. In 8 of 10 studies, serum HDL-C concentrations increased on treatment and this was associated with increases in apoproteins A1 and A2. Serum triglyceride levels also increased but no change occurred in serum cholesterol or LDL-C levels. Haematological factors were assessed in 8 studies and only minor changes were observed. Serum binding protein (SHBG, CBG, caeruloplasmin) concentrations increased and serum androgen levels decreased. Measurements of blood FSH, LH, oestradiol and progesterone indicated adequate inhibition of ovulation. Mercilon is the only oral contraceptive containing 20 micrograms ethinyloestradiol to have high efficacy, to have no adverse pharmacodynamic effects and, importantly, to produce an acceptable bleeding pattern not significantly different from that of oral contraceptives with a higher content of ethinyloestradiol.

Long-term use of depot-norethisterone enanthate: effect on blood lipid fractions

This is the third report of a metabolic study on 56 long-term users (24 for 2-5 yr; 32 for over 5 yr) of the injectable contraceptive norethisterone enanthate (Net-En) and deals with the effects on the blood levels of lipoprotein fractions. There was no significant difference between this group and a group of 30 non-users in serum concentrations of triglycerides, total cholesterol, low density and very low density lipoproteins. There was a significant reduction in mean high density lipoprotein levels between the controls and the user groups (16% for the intermediate duration and 12% for the longer duration). Age, ethnic group, body-mass index and a close family history of cardiovascular disease were taken into account, as were various lifestyle factors: diet, exercise, alcohol consumption and smoking. In a smaller group, levels of apoproteins A and B were also assayed. There was a significant reduction in apoprotein A between controls and all users, but the significance was lost on adjusting for confounding variables. Consideration was given to the ratio of total cholesterol to high density lipoprotein cholesterol as an index of coronary risk. There were no significant differences in the total cholesterol:HDL-C ratio between controls and user groups. There was a significant interaction with ethnic group (Caucasian or Afro-Caribbean) in the response to duration of use.

A cross-over study of three oral contraceptives containing ethinyloestradiol and either desogestrel or levonorgestrel

A randomised cross-over trial was performed to compare the pharmacodynamic actions of three low-dose oral contraceptives (OCs): Marvelon (150 micrograms desogestrel (DSG)+ 30 micrograms ethinyloestradiol (EE)), Mercilon (150 micrograms DSG + 20 micrograms EE) and Microgynon (150 micrograms levonorgestrel (LNG) + 30 micrograms EE). None of the OCs produced any significant changes in serum cholesterol, LDL-C and apoprotein B. Triglycerides were increased by the desogestrel OCs but not by Microgynon. The latter however increased the glucose and insulin responses to a glucose tolerance test whereas Marvelon and Mercilon had no effect. HDL-C increased with Marvelon, was unchanged with Mercilon and was decreased with Microgynon. Apoprotein AII was increased by all three OCs but only the DSG OCs increased apoprotein AI. All OCs produced similar increases in caeruloplasmin but the increase in SHBG was much greater with Marvelon and Mercilon than with Microgynon. Testosterone was reduced more with Microgynon than with the DSG OCs. Many of the changes reflect the strong anti-oestrogenic action of LNG on metabolic parameters compared to DSG. Except for the effect on HDL-C, there was little difference between Marvelon and Mercilon on metabolic parameters and this complements the findings from large-scale clinical trials of the two OCs. Mercilon, therefore provides a very satisfactory alternative to Marvelon.

Intrasubject variability in the pharmacokinetics of ethynyloestradiol

Intrasubject and intersubject variability in the metabolism of ethynyloestradiol (EE) was assessed in a cross-over randomized study of 6 women who each received 3 months treatment with 50 micrograms EE and 50 micrograms EE with 250 micrograms levonorgestrel (LNG). Blood samples were collected at the end of each treatment month, assayed for EE and the half-life of elimination (Tel) and bioavailability (area under the serum concentration-time curve, AUC) calculated. Intrasubject variability for Tel and AUC varied markedly; the variability was random and not correlated with the formulation administered. The intrasubject variability for Tel and AUC was 31 and 17%, respectively, and intersubject variability 66 and 95%. The intersubject range of values was more than 3-fold for both Tel and AUC and the intrasubject range about 2-fold. The pharmacokinetics of EE were not influenced by LNG; mean values for Tel and AUC were 17.3 +/- 5.5 h and 11.1 +/- 3.8 ng/ml/h, respectively, when EE was administered alone compared with 16.4 +/- 4.8 h and 12.5 +/- 3.9 ng/ml/h when given with LNG. However, EE influenced the metabolism of LNG; Tel for LNG was 19.3 +/- 4.2 h when administered alone and significantly higher (30.0 +/- 11.2 h) when given with EE. There was no correlation between the rate of metabolism of EE and that of LNG. The intrasubject variability shown in this and other studies suggests that genetic factors are less important in intersubject variability than previously thought. Some implications of intrasubject variability are discussed.

Interactions with oral contraceptives

The interaction of a range of different factors with the pharmacologic activity of oral contraceptives is reviewed. Pharmacokinetic interactions with oral contraceptives may occur (1) during absorption and extrahepatic circulation, (2) by interfering with protein binding, and (3) during hepatic metabolism. The hepatic mixed function oxidase system, which is mainly responsible for the metabolism of oral contraceptives, is affected by several different factors and is easily induced. Nutrition affects the activity of many drugs, but information regarding oral contraceptives is meager. Both pharmacokinetic and pharmacodynamic interactions, which may be synergistic or antagonistic, between the estrogen and gestagen components of oral contraceptives, are important, but there is no correlation between the rate of metabolism of the two components. Evidence suggests that some anticonvulsant, antibiotic, and antibacterial drugs may reduce the efficacy of oral contraceptives. Instances of interactions of other therapeutic agents are reported infrequently. The incidence of serious interactions is low and does not appear to have been reduced with low-dose oral contraceptives, probably because of large intersubject variability in the pharmacokinetics of oral contraceptives.

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.

A pharmacodynamic and pharmacokinetic study of the Chinese No. 1 pill

A pharmacodynamic and pharmacokinetic study of the Chinese No. 1 pill, a combined oral contraceptive containing 35 micrograms ethynyloestradiol (EE) and 600 micrograms norethisterone (NET), was performed in 29 women over a period of six months. Blood samples for analysis were taken during a pretreatment cycle, the first and 6th treatment cycles and post-treatment. Minor changes in carbohydrate metabolism occurred and these were particularly noticeable when the incremental areas under the serum concentration-time curves for both glucose and insulin in response to a glucose tolerance test were calculated. No changes occurred in the serum glycosylated haemoglobin levels. The serum concentrations of all the lipids measured (total cholesterol, triglycerides, LDL-C, HDL-C and apolipoproteins AI, AII and B) were significantly increased on treatment as were levels of Factor X, SHBG and caeruloplasmin whereas antithrombin III decreased. In 38 of the 40 treatment cycles, ovulation was suppressed. In one cycle serum oestradiol and progesterone levels showed a typical ovulatory pattern and in another there was evidence of follicular activity without ovulation. Serum EE concentrations showed a similar pattern in both treatment cycles showing that co-administration of NET did not affect EE metabolism. Serum NET levels were higher in the 6th than in the first treatment cycles. On comparing pharmacodynamic and pharmacokinetic parameters, the only statistically significant correlations were between the percentage change in triglycerides and SHBG and serum NET, but not EE concentrations, and between apolipoproteins AI and serum EE.

Hemostatic changes in women using a monthly injectable contraceptive for one year

The effect of consecutively injecting a one-a-month contraceptive (norethisterone enantate 50 mg with estradiol valerate 5 mg) for one year on haematological parameters was evaluated in 42 Chinese women. The healthy volunteers were randomly allocated to either the treatment group (22) or a control group (20). Blood samples were collected in the follicular and luteal phases of a pretreatment cycle, on days 28 +/- 3 after the 1st, 3rd, 6th, 12th injections and in the luteal phase of the post-treatment cycle. The results showed that in both groups, prothrombin time and fibrinogen fluctuated significantly, and leucocyte count was not significantly changed during the whole course. Factor VIII-related antigen and antithrombin III (AT-III) antigen showed minor changes, although in the 3rd treatment cycle, the differences between the two groups in both parameters reached statistical significance. A progressive and significant decrease in Factor X and AT-III functional activity occurred with the monthly injectable treatment, decreasing by about 14% and 20%, respectively, after 12 months of treatment. Haemoglobin levels were increased in the treatment group after the 3rd injection and remained at the higher level during the study period. It is doubtful whether these changes are likely to be of clinical relevance.

Pharmacokinetics of gestagens: some problems

Various approaches to studying the pharmacokinetics of gestagens and the factors that influence derivation of the parameters are described with levonorgestrel used as an example. Published studies of the pharmacokinetics of levonorgestrel are reviewed, and new information is presented regarding intra- and intersubject variation. Differences between various formulations of levonorgestrel are apparent when the formulations are compared in the same subjects. There is also a marked difference in the parameters when derived under single-dose or steady-state conditions. The role of sex hormone-binding globulin in the metabolism of levonorgestrel is questioned. Large intra- and inter-subject variations in the parameters exist, and a subject may show a large month-to-month variation when one levonorgestrel formulation is used and smaller variations when another formulation is used. This wide variability in the pharmacokinetic parameters, problems that arise in the derivation and interpretation of the parameters, the biologic significance of most of these parameters, and their lack of correlation with pharmacodynamic responses severely limit the usefulness of pharmacokinetic studies of the gestagens.

Comparative cross-over pharmacokinetic study on two types of postcoital contraceptive tablets containing levonorgestrel

A pharmaceutical and pharmacokinetic study was carried out on levonorgestrel tablets from two different sources (Hungarian- and Chinese-made). Both preparations contained 0.75 mg levonorgestrel and had been shown to have similar contraceptive efficacy and side effects when used for postcoital contraception. Absorption and bioavailability of the Hungarian-made tablets were greater as evidenced by higher serum concentrations of levonorgestrel, a greater area under the concentration-time curve during the first 24 hours, and a more marked suppressive effect on SHBG levels. These differences most probably reflect differences in their pharmaceutical formulation, in particular the extent of tablet dissolution and the degree of micronisation of levonorgestrel.

Potency and pharmacokinetics of gestagens

Serum concentrations of gestagens were compared after single doses and after multiple doses (steady-state conditions) of four widely used oral contraceptives containing norethisterone (NET), levonorgestrel (LNG), desogestrel (DSG) and gestodene (GSD). There were marked differences among the gestagens with respect to the serum concentrations. Under steady-state conditions 12 h after dosing, the relative concentrations were approximately GSD, 4.5:DSG, 1:LNG, 1:NET, 2 compared to ratios of 1:2:2:13.3, respectively, for dose. Thus, there was no correlation between serum concentration and dose. These differences in serum concentrations are determined by the different pharmacokinetic behaviour of the gestagens, which in turn is largely determined by their binding to serum proteins. Calculations suggest that the concentrations of unbound gestagen in serum, and hence probably also at the target organ, are similar (about 35 pg/ml) for LNG, DSG and GSD but may be higher (up to 60 pg/ml) for NET whose half-life of elimination is about half that of the other three gestagens. Measurement of the serum total concentration is unlikely to correlate with their pharmacological activity. A further complication is the multiplicity of pharmacological effects elicited by the gestagens and each of these effects is likely to have its own dose-response relationship.

Pharmacokinetic study of orally administered RU 486 in non-pregnant women

A method based on HPLC was devised for the estimation of RU 486 in blood and utilised to study the pharmacokinetics of a single dose of 50 mg RU 486 administered orally to 12 women on day 7 of the cycle. The dose was rapidly absorbed with peak plasma concentration between 1 and 2 hours. Distribution was also rapid (mean t1/2 alpha: 1.4h), whereas elimination was slow (mean t1/2 beta: 28.3 h). RU 486 was still detectable in some women at 72 h after administration. The plasma concentrations fitted the equation for a two-compartment open model from which the pharmacokinetic parameters were calculated. The mean total plasma clearance was 3.0 l/h, and the comparison of our data with those published studies suggests that the pharmacokinetics of RU 486 in Chinese women are similar to those of other populations.

Effect of some oral contraceptives on serum concentrations of sex hormone binding globulin and ceruloplasmin

Serum SHBG and ceruloplasmin (CP) concentrations were measured in women throughout a cycle of treatment with four oral contraceptives. In women receiving 150 micrograms levonorgestrel (LNG) daily both SHBG and CP decreased. SHBG also decreased, but CP increased, in women receiving ethynyloestradiol (EE) 30 micrograms with LNG 150 micrograms. In women taking 35 micrograms EE with either 600 micrograms or 1000 micrograms norethisterone, increases in CP were similar but SHBG increased more with the lower dose. Serum concentrations had not returned to pretreatment levels by eight days after cessation of dosing. The findings are compared with similar results for women taking 30 micrograms or 50 micrograms EE or an EE,LNG triphasic formulation. Serum concentrations of the gestagens were also measured. Increases in these concentrations when the gestagen was administered with EE to levels higher than expected from administration of the gestagen alone cannot be explained by increased binding to SHBG but are more likely to be due to changes in their metabolism. Differences in the responses of ostensibly closely related proteins of hepatic origin such as SHBG and CP to the oral contraceptives demonstrate that neither can be extrapolated to other pharmacodynamic responses.

Metabolic changes in women using a long-acting monthly oral contraceptive and return of ovulation on discontinuation

Metabolic changes were investigated in two groups of women using oral contraceptives for 5 to 16 years. Blood samples were taken during the last cycle of oral contraceptive use and three months post-treatment. One group had used a monthly oral contraceptive (MOC, 3mg quinestrol and 10mg 16-methylene chlormadinone acetate) and the second group a daily oral contraceptive (DOC, 35 micrograms ethynylestradiol and 0.625 mg norethisterone). During treatment there were increases in serum total cholesterol and triglycerides but not HDL-C, in plasma total cortisol but not in renin activity, angiotensin II or urinary free cortisol excretion, in hemoglobin and some coagulation factors but not Factor X or antithrombin III, platelet function or fibrinolysis. The area under the blood glucose concentration-time curve, but not that for serum insulin, was slightly increased and there was no change in fasting blood sugar concentrations. All metabolic parameters, except plasma cortisol, which had shown an increase on treatment, had decreased to control levels within 3 months. Ovulation returned promptly in all women, the mean time being 70 days for Group MOC and 44 days for Group DOC. Thus, in spite of the long duration of use of the oral contraceptives, metabolic changes were minor.

Pharmacokinetic study of levonorgestrel used as a postcoital agent

The pharmacokinetics and pharmacodynamics of levonorgestrel (LNG) were studied in six women given 0.75 mg LNG orally for seven days during the periovulatory phase of the menstrual cycle. Steady-state concentrations of LNG were reached within three days and serum LNG concentrations at various times on day 7 were generally lower than on day 1, presumably due to a reduced serum level of SHBG. On day 7 the volume of distribution was significantly increased and Co significantly decreased and both the clearance and elimination half-life were higher on day 7 than on day 1. Half-lives varied from 5.6 to 25.1 hours. The day-to-day intra-subject variations in serum LNG concentrations ranged from 23% to 80%. Serum concentrations of pituitary and ovarian hormones suggested that ovulation was not inhibited in four of the six subjects and was delayed in the remaining two. No significant changes in serum prolactin levels were observed.

Effect of Anordrin on serum levels of sex hormone binding globulin, caeruloplasmin and ovarian function

Ten doses of 7.5 mg Anordrin were administered on alternate days from day 5 of the menstrual cycle to 20 women. Serum concentrations of both SHBG and CP were significantly increased after the fourth dose but the increases were minor compared to those produced by ethynyloestradiol. Two weeks after stopping Anordrin, serum concentrations of the proteins were still elevated in most women. Ovarian activity was studied in 8 women; serum oestradiol and progesterone concentrations indicated that ovulation occurred at the normal time in three women but was delayed for two weeks or more in the remaining five. The findings suggest that in humans, Anordrin acts as a weak oestrogen and may also have antioestrogenic activity.

Pharmacokinetics of norethisterone in humans

The pharmacokinetics of a dose of 1mg norethisterone administered with 50 micrograms ethynyloestradiol was studied in 83 subjects. The dose was rapidly absorbed and there were wide variations in the serum NET concentrations at any particular time after dosing; the concentrations at 24 h varied from 100 to 1700 pg/ml. There was a significant negative correlation between the serum NET concentration and the time after dosing in all women. There were large inter-subject variations in the pharmacokinetic parameters, the elimination half-life and bioavailability showing 3- and 5- fold variability, respectively. Mean values for the parameters were t1/2, 7.6 h; bioavailability, 53.6 ng/ml/h; C max, 4.63 ng/ml; clearance, 22.6 l/h; and Vd 2361. There were a number of statistically significant correlations between the pharmacokinetic parameters and analysis of the correlations suggested that clearance was an important determinant of the bioavailability and of C max whereas the elimination half-life was the determinant of the NET concentration at 24 h. The pharmacokinetics of NET are compared with those of ethynyloestradiol. The wide variation in pharmacokinetics is likely to be important in determining inter-subject variations in efficacy and, particularly, side-effects of oral contraceptives especially now that low-dose formulations are widely used.

Metabolic investigations with Femodene--an oral contraceptive containing gestodene and ethinyloestradiol

The metabolic effects of a new oral contraceptive Femodene (SHD 356C) containing 75 micrograms gestodene (delta-15-levonorgestrel) and 30 micrograms ethinyloestradiol were studied in two groups of women. Group 1 consisted of women not currently using oral contraceptives; Group 2 consisted of women switching to Femodene from their current oral contraceptive. Changes in lipid metabolism were assessed by measuring serum levels of cholesterol, triglycerides, LDL-C, VLDL-C, HDL-C, HDL2-C and HDL3-C. Minimal changes occurred in lipid metabolism apart from increases in triglyceride concentrations. Women in Group 1 showed a 105% increase in SHBG levels and a 51% increase in caeruloplasmin levels compared to increases of 33% and 2% in women in Group 2. A comparison of the two groups of women suggested that the gestagen in Femodene exerted a less anti-oestrogenic effect than most of the gestagens currently used in oral contraceptives. No significant changes occurred in liver function (assessed by estimation of gamma-glutamyl transferase) or in the coagulation factors, Factor X and antithrombin III. Minor effects on glucose tolerance as assessed by blood glucose and plasma insulin levels were noted. These minimal effects on metabolism, combined with its high efficacy and acceptability shown in clinical trials, makes Femodene an ideal alternative to currently used oral contraceptives.

A pharmacokinetic and pharmacodynamic study of a 'visiting pill' containing norethisterone

The pharmacokinetics and pharmacodynamic effects of two doses of norethisterone (5mg and 3mg) used as a 'visiting pill' were investigated. There were no significant differences in the pharmacokinetics of the two doses except for the peak concentration achieved and the bioavailability as assessed by the area under the serum norethisterone concentration - time curve. Both doses were rapidly absorbed. Pharmacodynamic effects were minor. No change occurred in serum concentrations of total cholesterol, total triglycerides or HDL-cholesterol. The area under the serum glucose concentration--time curve and particularly the area under the serum insulin concentration--time curve were significantly increased as a result of treatment but no change occurred in the serum levels of glycosylated haemoglobin. SHBG concentrations in serum decreased on treatment whereas those of ceruloplasmin increased.

Effect of oral contraceptives on serum apoprotein levels

The effect of oral contraceptives on serum lipoprotein concentrations, as assessed by their cholesterol content, is determined by the doses of estrogen and progestogen and the type of progestogen they contain. Assay of the apoprotein content, instead of cholesterol content, measures a different aspect of lipoprotein metabolism. Changes in serum concentrations of apoproteins A and B in women using oral contraceptives are similar to those obtained by measuring low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol.

Oral contraceptives, lipids and cardiovascular disease

Evidence for the involvement of changes in lipid metabolism and oral contraceptive use in the development of cardiovascular disease is briefly reviewed with particular reference to the main object of the article, to assess the effect of different oral contraceptive formulations on serum lipid levels. The preferred formulations should contain a low dose of ethynyloestradiol and should not increase serum levels of cholesterol and LDL-C or reduce those of HDL-C. Such formulations appear to be the triphasic one containing ethynyloestradiol and levonorgestrel and the ethynyloestradiol-desogestrel combination, which appears to be unique in that it may actually increase HDL-C. However other determinants in addition to effects on lipid metabolism will be important in deciding the choice of an oral contraceptive. Any changes which do occur in serum lipid concentrations with OC use appear within the first three months and do not appear to be progressive with continued use after this time.

An evaluation of high-dose medroxyprogesterone acetate (MPA) therapy in women with advanced breast cancer

The efficacy of high-dose intramuscular MPA therapy in controlling progressive measurable metastatic breast carcinoma was assessed in 32 women. In addition serial measurements of MPA blood levels were carried out in 20 of the patients and subjective effects of treatment were monitored in detail in 18 of the women. Overall 6 patients (19%) gained an objective response and a further 7 (22%) experienced disease stasis from 4-17 months whilst on treatment. Significant differences in serum MPA levels were seen between responders and non-responders, objective tumour shrinkage only being seen in those patients who rapidly attained, and sustained, blood levels in excess of 100 ng ml-1. Subjective assessment showed no evidence of a euphoriant effect of MPA therapy in the non-responders group.