Comparison of metabolic and clinical effects of four oral contraceptive formulations and a contraceptive vaginal ring

Comparison of the metabolic effects of oral contraceptive and nonhormonal contraceptive use in women over 40 years old

The aim of this study was to compare metabolic changes during use of low-dose combined oral contraceptives (COCs) and those of nonhormonal contraceptives in perimenopausal women. Thirty-nine healthy women over 40 years old who attended the Family Planning Clinic of the King Chulalongkorn Memorial Hospital, Bangkok, Thailand, were recruited, 20 in the COC group received COC preparations containing 30 microg of ethinyl estradiol and 150 microg of levonorgestrel and 19 in the nonhormonal group were intrauterine device users. Blood samples were taken upon admission and 6 months later. Minor biochemical changes associated with low-dose COC use included an increase in glucose tolerance, triglycerides, serum albumin, serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) levels but a decrease in fasting plasma glucose, total cholesterol, high-density lipoprotein cholesterol, total bilirubin and alkaline phosphatase levels. There was no clinical significance for the metabolic changes. Low-dose COCs can be a satisfactory contraceptive choice for healthy perimenopausal women.

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.

Lipid and biochemical changes after low-dose oral contraception

A randomized double-blind study of the metabolic effects of 2 low-dose combined oral contraceptives was carried out in Singaporean women. The subjects comprised 58 women randomly allocated to two treatment groups (29 each): norethisterone 1 mg/ethinyl estradiol 35 micrograms (NET/EE) or levonorgestrel 150 micrograms/ethinyl estradiol 30 micrograms (LNG/EE) and a control group of 23 women using intra-uterine devices (IUD). Blood samples were taken on admission and at 3 and 12 months after pills or insertion of IUDs. Fasting glucose levels were decreased while 2h glucose and triglyceride were increased throughout the treatment period in NET/EE group [corrected]. LNG/EE group only showed significant increase of 2h glucose at 12 months and decrease of LDL cholesterol at 3 months while total cholesterol was significantly suppressed at 3 and 12 months [corrected]. The atherogenic index, LDL/HDL cholesterol was significantly reduced by 12 months. Both groups had no change in hemoglobin, hematocrit and total protein levels but alkaline phosphatase, bilirubin and aspartate transaminase (SGOT) were suppressed. While NET/EE suppressed albumin significantly, this was not observed with LNG/EE group. However, these differences observed with use of each pill preparations, were not so obvious between treatment groups and control. Changes in total, HDL and LDL cholesterol and SGOT were not significantly different than the IUD group. Furthermore, except for 2h glucose, there was no increase in the number of abnormal parameters after treatment. On the contrary, there was a reduction of abnormal values in most liver function parameters. Thus, except for glucose intolerance, the observed changes in metabolic parameters may not constitute any clinical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative metabolic study of percutaneous versus oral micronized 17 beta-oestradiol in replacement therapy

The aim of this study was to compare the metabolic effects of two presentations of 17 beta-oestradiol (E2) which are of recognized effectiveness in the prevention of post-menopausal bone loss, one being administered via the oral and the other via the percutaneous route. During this prospective, randomized study, 32 patients were treated for 2 mth with either 2 mg/day of oral micronized E2 (n = 16) or 1.5-3 mg/day of percutaneous E2 (n = 16). Both regimens proved efficacious, since significant increases in oestrone (E1) and E2 concentrations ranging up to mid-follicular values were observed. In the percutaneous-treatment group we noted a significant decrease in triglycerides (TG), without any significant changes in high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein cholesterol (LDL-C). In the oral-treatment group, we saw no significant increase in HDL-C, although significant increases were observed in body weight, TG, plasma renin substrate (PRS) and sex-hormone-binding globulin (SHBG) as well as significant decreases in antithrombin III (AT III) activity and antigen. All of these metabolic variations led us to the conclusion that oral E2 at the dose established as effective in preventing post-menopausal osteoporosis may, even when micronized, alter certain metabolic and haemostatic parameters in a population characterized by increases in cardiovascular risk factors and morbidity. Oral oestrogen replacement therapy should therefore continue to be used only in carefully selected patients and be strictly followed up by systematic checks on a series of metabolic criteria.

Contraceptive steroids and coronary artery atherosclerosis in cynomolgus macaques

The influence of two types of steroidal contraception on the extent of coronary, aortic, carotid, and iliaco-femoral atherosclerosis was assessed in 57 cynomolgus macaques with moderate diet-induced hyperlipoproteinemia. Thirteen animals were treated with an intravaginal ring that released 17 beta-estradiol and levonorgestrel. Fifteen females were treated with an oral contraceptive (OC) composed of ethinyl estradiol and norgestrel. Fifteen females received placebo vaginal rings, and 14 males were untreated. The contraceptive treatments resulted in similar large reductions in plasma high-density lipoprotein (HDL) cholesterol concentrations. Neither treatment influenced the prevalence of coronary artery atherosclerosis. However, treatment with the contraceptive vaginal ring was associated with increased extent of coronary artery atherosclerosis (plaque size) relative to untreated females, whereas treatment with the OC was not. The contrasting effects of the two treatments could not be explained by differences in total plasma cholesterol, HDL cholesterol, or blood pressure. The results suggest that the greater estrogenic influence associated with the ethinyl estradiol-containing OC resulted in inhibition of coronary artery atherosclerosis despite a pronounced progestin-induced lowering of plasma HDL cholesterol concentration and, further, that hormonal balance may have a marked influence on the relationship between plasma lipids and atherogenesis.

A comparison of a new graduated estrogen formulation with three constant-dosed oral contraceptives

Four-hundred-twenty-six women, aged 18 to 36, completed a four-cycle comparative, randomized, single-blind (observer blind), multicenter study of a new graduated estrogen formulation with three constant-dosed combination oral contraceptives containing the same synthetic steroid compounds. The products studied were Loestrin 1/20, Loestrin 1.5/30, Norlestrin 1/50, and a new graduated estrogen product, Estrostep. A total of 1,850 cycles were completed and analyzed for efficacy, side effects, metabolic changes, and cycle control. Four pregnancies occurred during the course of the study. None of the pregnancies occurred in the group receiving Estrostep. The new formulation produced the lowest rate of breakthrough bleeding (BTB) compared with the other three products. All four combination oral contraceptives resulted in an increase in high-density lipoprotein cholesterol (HDL-C). The levels of HDL-C were greatest with Estrostep.

Estrogen receptors and androgen receptors in the mammalian liver

An estrogen receptor and an androgen receptor are present in the mammalian liver. In the liver of the rat, the estrogen receptor concentration increases markedly at puberty and this change correlates with enhanced estrogen stimulation of plasma renin substrate synthesis. High doses of estrogen are required for nuclear binding in liver when compared to doses for the uterus. The high dose requirement appears to be predominantly due to extensive metabolism in the hepatocyte of the estrogen to inactive derivatives. Furthermore, estradiol is much weaker than ethinyl estradiol for promoting nuclear binding in the liver. This is due to extremely rapid and extensive metabolism of estradiol. In human liver the concentration of estrogen receptor is low. An androgen receptor is present in high concentration in rabbit liver and is located predominantly in the nucleus after androgen administration. High concentrations of a putative androgen receptor are also present in human liver cytosol. Preliminary studies indicate that synthetic progestins can attach to the human liver androgen receptor. To date, a progesterone receptor has not been found in the mammalian liver. Thus, it appears that extensive steroid metabolism in liver preferentially diminishes sex steroid interaction with liver receptors and that androgen receptors may mediate progestin effects in liver. These observations provide a scientific basis for improved safety of oral contraceptives. Lowering the estrogen and progestin doses in oral contraceptives will decrease the major side-effects, which are liver mediated, and still maintain the desired effects at the hypothalamic-pituitary axis and uterus. Furthermore, it is likely that by selecting which estrogen, progestin or androgen is administered as well as by utilizing a parenteral route of administration that sex steroid effects on the liver could be minimized.

A randomized double-blind study of the effects of two low-dose combined oral contraceptives on biochemical aspects. Report from a seven-centred study. WHO Special Programme of Research, Development and Research Training in Human Reproduction. Task force on Oral Contraceptives

A comparative study of the metabolic effects of two combined oral contraceptive preparations was undertaken in seven WHO Collaborating Centres for Research in Human Reproduction. A total of 847 subjects were randomly allocated to one of two pill groups - norethisterone lmg/ethinyl estradiol 35 micrograms (NET/EE) or levonorgestrel 150 micrograms/ethinyl estradiol 30 micrograms (LNG/EE). An additional 195 women using an IUD served as a comparison group. Blood samples were taken on admission, and at 3 and 12 months thereafter. Both pills induced changes in fasting and 2-hour glucose, triglycerides, total cholesterol, HDL-cholesterol, bilirubin, alkaline phosphatase, albumin, and total protein, but not aspartate aminotransferase. The most dramatic and probably most clinically important changes were an increase in triglycerides and a decrease in HDL-cholesterol. The NET/EE preparation appeared to induce a greater increase in triglycerides, but no significant difference was found between the two pill preparations with respect to HDL-cholesterol changes.

Pharmacokinetic interaction of contraceptive steroids with prednisone and prednisolone

The oestrogenic component of oral contraceptives affects the activity of liver enzymes and the concentrations of plasma proteins implicated in steroid metabolism and transport. The present study was designed to determine these effects on the kinetics of prednisone and prednisolone. After an oral dose of prednisone, women on oral contraceptive steroids (n = 10) had higher mean (+/- SD) area under the plasma concentration versus time curves of total (428 +/- 67 micrograms/ml/min vs 188 +/- 28 micrograms/ml/min, p less than 0.001) and unbound prednisolone (64 +/- 10 micrograms/ml/min vs 41 +/- 10 micrograms/ml/min, p less than 0.001) than women not taking oral contraceptive steroids (n = 10). The differences were attributable to a lower non-renal clearance of prednisolone and to a higher apparent systemic availability of the drug in contraceptive users than in the controls. The affinity of albumin and transcortin for prednisolone was lower in women on oral contraceptives than in controls (p less than 0.001). Thus, altered kinetics and protein binding may account for the known increase in glucocorticoid efficacy by oestrogens.

Effects of two low-dose oral contraceptives on serum lipids and lipoproteins: differential changes in high-density lipoprotein subclasses

Oral contraceptives containing DL-norgestrel or norethindrone with ethinyl estradiol were administered by random assignment to 21 menstruating women, matched for anthropometric measurements, age, diet, alcohol consumption, smoking, and exercise habits. Pretreatment and 7-week treatment blood samples were obtained and assayed for serum cholesterol, triglyceride high-density lipoprotein cholesterol (HDL-C), and total high-density lipoprotein (HDL), HDL2a, HDL2b, and HDL3 subclasses by analytic ultracentrifugation. Subjects using the norethindrone oral contraceptive had a significant increase in HDL-C: baseline, 46 mg/dl; 7 weeks, 51 mg/dl. Values for the subjects using the norgestrel oral contraceptive were not significantly changed: 46 and 44 mg/dl, respectively. Users of the norethindrone oral contraceptive had significant elevations of total HDL and HDL3, while norgestrel oral contraceptive users demonstrated no significant changes. HDL2b increased with the norethindrone oral contraceptive and declined with the norgestrel oral contraceptive. The changes in HDL2b from baseline to treatment were not significant (p greater than 0.05), but the change with the norethindrone oral contraceptive did differ significantly from that with the norgestrel oral contraceptive (p less than 0.02). These changes may indicate oral contraceptive-induced alterations in HDL structure and metabolism that could be related to the risk of development of atherosclerosis.

The effect on lipids and lipoproteins of a contraceptive vaginal ring containing levonorgestrel and estradiol

Lipids and lipoproteins were studied in controls and women using contraceptive vaginal rings (CVRs). The groups were comparable for race, age, parity, obesity indices, alcohol ingestion, smoking, diet and exercise. Fasting blood samples were obtained twice before CVR treatment, after 2 and 7 weeks of treatment and 1 week thereafter. The women using the CVR had a significant incremental reduction of cholesterol from baseline to treatment which was distributed among all the lipoprotein classes. The cholesterol/HDL-C ratio was significantly increased with treatment. All mena changes were within the reference range. The reduction in HDL and especially in the subclasses HDL 2a and HDL 2b were significant and outside the reference range. The LDL/HDL ratio increased significantly, while the LDL/HDL 2a+2b ratio increased significantly outside the reference range with treatment. Of the lipid and lipoprotein measurements that changed significantly with treatment, HDL-C, HDL, HDL 2a LDL/HDL and LDL/HDL 2a+2b changed significantly towards baseline in the 1-week-off treatment. The potential reduction in predicted coronary risk with the use of the CVR suggested by a reduction in cholesterol was counterbalanced by a reduction in HDL-C and increases in the cholesterol/HDL-C and LDL/HDL ratios. The potential clinical implications of these findings remain to be determined.