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.

Hormonal postcoital contraception with an ethinylestradiol-norgestrel combination and two danazol regimens

The ethinylestradiol-norgestrel combination (EE-NG) for postcoital contraception, as described by Yuzpe, has been shown to be an effective method but with frequent side effects. To overcome the problem of adverse effects a new approach using danazol was proposed, but the efficacy and acceptability of this treatment have not yet been tested in large studies. In a 5-year period at the AIECS Family Planning Centre in Milan we treated 2448 women requesting postcoital contraception using Yuzpe's regimen and two danazol regimens (800 mg/1200 mg). The patients' acceptability for danazol treatment was higher than for Yuzpe's regimen due to fewer, milder and shorter side effects. Nine pregnancies occurred in the EE-NG group (2.21%), 17 in the 800 mg group (1.71%) and 6 in the 1200 mg group (0.82%). Our study shows a statistically significant efficacy against expected pregnancy rates both with Yuzpe's regimen and with danazol. The 1200 mg danazol treatment seems to be more effective and can be considered a valid alternative to the EE-NG combination for hormonal postcoital contraception.

[Oral contraceptives and blood diseases are the most common causes of Budd-Chiari syndrome]

Two cases of young patients with the chronic form of Budd-Chiari syndrome are reported. The first concerns a 22-year-old woman with a 6-month history of hepatomegaly, who had used oral contraceptives almost continuously during the five years preceding diagnosis. In a thorough diagnostic work-up, thromboses were detected in all but one of the hepatic veins, and a possible non-occluding thrombosis in the retrohepatic portion of the inferior vena cava. In the blood and bone marrow, findings were compatible with polycythaemia rubra vera, and a high anti-cardiolipin antibody titre was found. The second case concerns a 25-year-old male smoker with normal bone marrow, who had thromboses in at least two of the hepatic veins, though the inferior vena cava was not occluded. In both cases a mesocaval shunt was interposed with synthetic grafts, and postoperatively the patients are doing well--at sixteen and five months, respectively. Both are maintained on anticoagulants, and even without diuretics there has been no recurrence of ascites. The woman takes a small dose of hydroxy-urea to control her hypercoagulability. To our knowledge, hers is the first case to be reported of Budd-Chiari syndrome with hypercoagulability due to the concomitant presence of oral contraceptives, polycythaemia rubra vera and anti-phospholipid antibodies.

Haemorheological consequences of oestrogen and progestogen therapy

A clinical investigation was undertaken of the haemorheological effects of short-term administration of synthetic sex hormones. In a randomised controlled investigative trial, groups of 20 women taking ethynyloestradiol, norethisterone, combined norgestrel and ethynyloestradiol or no therapy had their blood viscosity and its major determinants measured before and after 3 months of treatment. Oestrogens and progestogens, singly or in combination, were found to cause a rise in blood viscosity. Oestrogens did so by raising haematocrit and plasma fibrinogen, parameters that are similarly raised in other conditions such as pregnancy and following surgery when venous thromboembolism is common. The synthetic progestogen, on the other hand, raised the blood viscosity by increasing the haematocrit and decreasing erythrocyte deformability, parameters that are similarly altered in occlusive arterial disease. The combined preparation raised blood viscosity by altering all three parameters. These observations indicate the pathways whereby various synthetic oestrogens and progestogens in oral contraceptives or replacement therapy may be associated with different types of cardiovascular pathology.

Mini-pill in lactating women

A non-comparative study of the progestogen-only oral contraceptive, norgestrel 0.075 mg, in breast-feeding women was conducted at the Centro de Investigaciones Regionales, Merida, Yucatan, Mexico. The study was designed to evaluate the overall acceptability and contraceptive efficacy of norgestrel in breast-feeding women. This report includes a survey of 200 women, all of whom were less than 26 weeks postpartum at admission; 113 were interval patients and 87 were postpartum. Follow-up visits were scheduled at 2, 6 and 12 months after admission. Overall, women experienced an increase in intermenstrual bleeding, amenorrhea, vaginal discharge and breast discomfort. The discontinuation rate at 12 months was 32.5 and the corresponding lost to follow-up rate was 22.5; this is a measure of acceptability. The 12-month life-table rate for pregnancy was 3.4 with a standard error of 2.0. Three women discontinued use of the mini-pill due to accidental pregnancy. One pregnancy was attributed to user failure and the woman conceived 9 months after entering into the study; the other two were attributed to method failure, one woman conceived 3 months after admission and the other conceived 6 months after admission.

Oral contraceptive use and the risk of chlamydial and gonococcal infections

Oral contraceptive users were compared with nonusers with respect to the rate of cervical infections by Chlamydia trachomatis and Neisseria gonorrhoeae. The comparison was adjusted for differences in demographic and behavioral characteristics between the two groups. The rates of infection among oral contraceptive users were increased by approximately 70% (statistically significant) for both pathogens. Cervical ectopy was implicated in the increased rate of chlamydia but not gonorrhea. Rates of gonorrheal infection differed significantly among oral contraceptive formulations; rates were higher for formulations containing more androgenic progestins.

[Danazol: a new hormonal post-coital contraceptive method]

During a 9-month period, 84 female patients received post-coital contraception consisting either of an association of ethinyl estradiol/norgestrel or of danazol, in order to compare the safety and any adverse reaction of these 2 treatments. Overall, the patients treated with danazol presented 1/3 as many side effects. Nausea was reduced to 1/3 in frequency and vomiting to 1/9 in this group. 5 pregnancies were confirmed in the ethinyl estradiol/norgesterol group and 2 in the danazol group. Although more cases are needed, it would appear that danazol is characterized by greater efficacy and patient acceptability.

Relative potency of progestins used in oral contraceptives

Epidemiologic studies indicate that the risk of complications with oral contraceptive use is related to the steroid content and potency of the various formulations. This paper summarizes human data in which potencies of progestins in oral contraceptives can be compared. Data on delay of menses and endometrial subnuclear vacuolization, an indirect assessment of glycogen deposition, are presented. The relative effects of various progestins on serum lipids and lipoproteins are also summarized. The object of this review is to examine the available scientific evidence which generally supports the conclusion that there is a marked similarity of potency of the dose of various progestins used in many of the formulations currently available in the U.S. The progestins norethindrone, norethindrone acetate and ethynodiol diacetate are roughly equivalent in potency while norgestrel is roughly five to ten times and levonorgestrel ten to 20 times as potent.

Effect of synthetic oestrogens and progestagens in oral contraceptives on bile lipid composition

The prevalence of cholesterol gall stones in young women has increased since the introduction of oral contraceptives. The synthetic female sex hormones used in these preparations, increase the degree of cholesterol saturation in bile. To determine whether oestrogens, progestagens, or both, are responsible for the change in biliary cholesterol saturation index, a prospective randomised, controlled study was performed. A significant increase in the cholesterol saturation index of bile was observed when either 30 micrograms ethinyloestradiol plus 150 micrograms norgestrel (p = 0.01) or 50 micrograms ethinyloestradiol plus 250 micrograms norgestrel (p less than 0.01) were ingested daily for two months. No change in the cholesterol saturation index was observed when 30 micrograms ethinyloestradiol alone, or 30 micrograms ethinyloestradiol plus 2.5 mg norethisterone were used. The mechanism for the increase in cholesterol saturation index did not appear to involve bile acid metabolism. These results indicate that the progestagen, norgestrel, and not as previously thought the oestrogen, ethinyloestradiol, is responsible for the increase in cholesterol saturation of bile which accompanies the use of oral contraceptives.

Oral contraceptives and their influence on porphyrin concentrations in erythrocytes and urine

In 15 females who have never before taken oral contraceptives, the porphyrin concentration in erythrocytes and in urine were investigated. The laboratory assays were performed before and after being on the oral contraceptive Stediril during 5 months (2 women took Stediril during only 3 months). The mean PP concentration in the erythrocytes increased from 16.4 microgram (before) to 24.1 microgram/100 ml of erythrocytes after taking Stediril regularly for 5 months. A statistical evaluation with the Student's test showed that at the level of 2%, the t(exp) = 2.58 was larger than the theoretical t(0.02) = 2.47. The difference of the mean CP concentration in the erythrocytes before and after taking Stediril was not statistically significant at the level of 5%. The mean concentration of CP in urine increased from 119.2 to 137.1 microgram in 1,000 ml. This difference was, however, not statistically significant at the level of 5% when assayed with the same test. There was no increase in UP concentration in urine.

[Acid-base balance immediately after administration of an oral contraceptive (author's transl)]

An increase in breathing activity has often been described for the secretory phase of the menstrual cycle, for gravidity and after intramuscular application of corpus luteum and follicle hormone. The reason for this has been assumed to be a direct interaction of the hormones in the respiratory center. A shortly published paper dealing with 50 women under long-term treatment with a combination of oestrogenes and gestagenes for oral contraception leads the author to the assumption, that a metabolic acidosis is the primary reaction, followed by an increase in breathing activity for respiratory compensation. In a long-term study it is difficult to differentiate between primary and secondary effects. Therefore in the present experiments arterial blood has been analyzed for PaO2, PaCO2, pH and hemoglobin in 49 subjects on day 1 without hormone administration and on day 2 prior to (9.00 a.m.) after (11.00 a.m., 1.00 p.m., 4.00 p.m.) administration of a combination of oestrogene and gestagene. From the measured values O2-saturation, standard-bicarbonate, buffer bases and base excess have been calculated by the Thews nomogram. By comparison of the results before and after hormone administration it was shown, that the primary effect is a metabolic acidosis, partly compensated during the next 7 h by respiratory adaptation. There is no indication for a primary respiratory alkalosis.

Oral contraceptives, anti-thrombin III and fibrinolytic activity in Africans

A comparison of the effects of progestogen-only and combined progestogen-oestrogen types of oral contraceptives on anti-thrombin III activity and fibrinolysis in African subjects in South Africa is reported. The changes in anti-thrombin III activity are similar to those reported in other races, but the augmentation of fibrinolytic activity is more marked than has been reported elsewhere. The possible significance of these findings is discussed.

Comparative studies of the ethynyl estrogens used in oral contraceptives. III. Effect on plasma gonadotropins

Twenty-one-day treatment cycles of ethynylestradiol or mestranol at dosages of 50 to 100 mug per day were administered to 191 normal volunteer women from six cycles, followed by six cycles of this estrogen treatment combined with 2.5 mg. of norethindrone acetate, 2 mg. of megestrol acetate, or 0.5 mg. of norgestrel. The drugs were prepared to insure uniform bioavailabiltiy. Plasma FSH and LH were determined by radioimmunoasay during the last week of medication intake in each cycle. In another study, a large number of blood samples were obtained at various times during the menstrual cycle from women using IUD's (as a control population) and from women who had been taking oral contraceptives regularly for 5 to 12 years. With the various estrogen treatments, the median FSH level showed no change at any estrogen dose at the end of the first cycle. From the second cycle on, a stable, dose-related fall was obtained with the 80 or 100 mug per day doses. The addition of any of the three progestins caused a prompt, stable, further fall in FSH level. By contrast, the median LH level rose in the first cycle with all estrogen regimens, and then fell progressively in a dose-related fashion in cycles 2 to 6. The addition of a progestational agent also caused a further prompt and stable fall in LH during cycles 7 to 12. Except for a minimal indication of greater LH suppression by ethynylestradiol as compared to mestranol at 50 mug per day, all other indices and dosages showed ethynylestradiol and mestranol to be essentially equipoten under these experimental conditions. Long-term administration of oral contraceptives produced a comparable degree of gonadotropin suppression. There was a suggestion of slightly less FSH suppression with agents using 50 to 75 mug per day of estrogen than from those with 100 mug per day. Both in normal controls (IUD cycles) and in cycles under chronic treatment with oral contraceptives, pulses of both FSH and LH were seen with some frequency, at times distant from the "periovulatory" period. The significance and origin of these random FSH and LH pulses is unknown.

Effects of continuous daily administration of 0.03 mg of d-norgestrel on the plasma levels of progesterone and the urinary excretion of oestrogens

Daily determinations of the plasma level of progesterone and the urinary excretion of oestrogens were performed in five subjects during one control cycle followed by three months of treatment with 0.03 mg of d-norgestrel.

The control cycles were ovulatory according to the parameters investigated, although one of the women showed a monophasic basal body temperature.

During treatment there was a tendency to a decrease of the oestrogen excretion. Three of the women showed one or several cycles with low progesterone levels. It is believed that this was due to a defective function of the corpus luteum.

It seems that the effect of the present drug on the corpus luteum activity was about equal to that of chlormadinone acetate 0.5 mg daily, while 0.3 and 0.5 mg of norethindrone depressed the function more markedly.