Pregnancy termination with a high and medium dosage regimen of RU 486

Oral medications for central serous chorioretinopathy: a literature review

Central serous chorioretinopathy (CSCR) is characterised by acute or chronic neurosensory detachments of the retina, usually in the posterior pole, with or without associated detachments of retinal pigment epithelium. Although the condition often resolves spontaneously, chronic and recurrent cases can lead to significant visual loss in the working population and it is thus increasingly recognised as an important public health issue. The uncertainty regarding the underlying cause of CSCR has led to a wide range of therapies being tried for this condition including photodynamic therapy, laser photocoagulation, anti-VEGF injections and a multitude of oral agents. This article aims to review the current evidence for oral agents that have been used for treatment of CSCR. A systematic literature search was conducted for articles published between 1980 to July 2018. A total of 73 articles were included. These studied the following oral medications: eplerenone, spironolactone, beta blockers, H. pylori agents, omeprazole, rifampicin, methotrexate, aspirin, acetazolamide, mifepristone, melatonin, finasteride, ketoconazole, antioxidants and curcumin phospholipid. Although none of the studies showed robust evidence of efficacy, the mineralocorticoid receptor antagonists, particularly eplerenone, appear to demonstrate the highest quality evidence for use in this condition. The review aims to give the reader an overview of the current available evidence for oral medications used in the treatment of CSCR in order to provide an evidence-based discussion with the patient and guide through possible options for treatment.

Gynaecological uses of a new class of steroids: the selective progesterone receptor modulators

Selective progesterone receptor modulators (SPRM) represent a new class of synthetic steroids, which can interact with the progesterone receptor (PR) and can exert agonist, antagonist or mixed effects on various progesterone target tissues in vivo. This review evaluates the actual and potential usefulness of SPRMs in gynaecology.

Mifepristone dose in the regimen with misoprostol for medical abortion

Medical abortion with the antiprogesterone mifepristone followed by a prostaglandin is highly effective and widely used. The mifepristone dose registered is a single dose of 600 mg followed by a suitable prostaglandin analogue 36-48 h later. The 600-mg dose was chosen arbitrarily, and later studies have proven one third of this dose to be equally effective when combined with a prostaglandin analogue. This report reviews published data on the efficacy of mifepristone in different doses and demonstrates that there are no differences neither clinically nor in pharmacokinetics if the dose is reduced to 200 mg.

Synergistic effects of DL111-IT in combination with mifepristone and misoprostol on termination of early pregnancy in preclinical studies

This study evaluated the effectiveness and acute toxicity of DL111-IT combined with mifepristone (RU486) and misoprostol (MISO) on early pregnancy termination. In the pregnant rats experiments, the ED(50) values of RU486 in two-drug combinations were 0.16 (combined with DL111-IT) and 0.40 (combined with MISO) mg x kg(-1) x d(-1), while in three-drug combination treatment group (DL111-IT 9.0 mg x kg(-1) (<ED(5)) + MISO 0.30 mg x kg(-1) + RU486 0.012-0.5 mg x kg(-1) x d(-1)), the ED(50) of RU486 was decreased to 0.07 (0.04-0.10) mg x kg(-1) x d(-1). In guinea pigs, significant enhancement of early pregnancy termination was only observed in three-drug combination treatment with MISO 0.10 mg x kg(-1) + RU486 0.05 mg x kg(-1) (<minimum effective doses) + high dosages of DL111-IT (0.05-0.10 mg x kg(-1)). DL111-IT induced pregnant rat uterine contraction in vitro, and the contractive efficacy was 60% of that induced by MISO. Multiple intramuscular injections of DL111-IT in vivo could significantly enhance the MISO-stimulated uterine contractions of pregnant rats in vitro. DL111-IT 600 mg x kg(-1) or RU486 1000 mg x kg(-1) induced pigeon vomiting, with latent periods of 32.3 +/- 12.0 min and 50.4 +/- 16.0 min, respectively. In three-drug combination group, the latent period of vomiting was significantly extended to 86.3 +/- 36.2 min. MISO also significantly decreased the frequency of vomiting within 4 h after administration of DL111-IT and RU486. In the experiment of mice acute toxicity, the LD(50) values and 95% confidence limit of DL111-IT (i.p.) alone and in combination with RU486 and MISO were 1379.4 (1278.2-1514.7) mg x kg(-1) and 1574.1 (1407.8-1762.7) mg x kg(-1), respectively. There was no significant difference. All data suggested that DL111-IT in combination with RU486 and MISO significantly increased the effect on early pregnancy termination without increasing acute toxicity compared to the treatment of DL111-IT alone, and this combination may be a promising regimen for early pregnancy termination.

A benefit-risk assessment of medical treatment for uterine leiomyomas

The growth of a uterine leiomyoma growth stops and regresses after the menopause suggesting that leiomyoma growth is dependent on ovarian steroids. Therefore, estrogen has received much attention as the major factor responsible for the development of uterine leiomyomas, but progesterone also plays an important role in development of this disease. Cytogenetic analyses of resected samples has revealed that about 40 to 50% of leiomyomas show karyotypically detectable chromosomal abnormalities. Gonadotrophin releasing hormone (GnRH) agonists exert their action through the suppression of endogenous gonadotrophins and gonadal steroid secretion. Significant reductions of uterine/leiomyoma volume under GnRH agonist therapy has been reported in several studies. However, the leiomyoma generally returns to its pretreatment volume within a few months after discontinuation of the GnRH agonist. To minimise the adverse effects of hypoestrogenism during GnRH agonist treatment, add back therapy can be used (estrogen-progestin, progestin alone and recently tibolone). Antiprogestins have a potential clinical utility in uterine leiomyomas. Mifepristone is a synthetic steroid with both antiprogesterone and antiglucocorticoid activities, that may have an inhibitory effect on growth of leiomyoma. Danazol is an isoxazole of 17beta-ethinyl testosterone, a synthetic steroid, which has a suppressive effect on sex hormone binding globulin concentrations, resulting in efficacy in the short-term treatment of uterine leiomyomas. Gestrinone is a tri-enic steroid with antiestrogen and antiprogesterone properties and has been shown to reduce uterine volume and stop bleeding. Growth factors play a relevant role on the pathophysiology of uterine leiomyoma and probably the inhibition of the action of growth factors on the myometrium will be the basis for future therapy. A number of agents are under investigation for treating uterine leiomyoma. Agents developed from increasing genetic knowledge of this condition could represent, in the next few years, new trends in the medical treatment of uterine leiomyomas.

Synergistic effects of DL111-IT combined with mifepristone on termination of early pregnancy in rhesus monkeys

The objectives of this study were to determine the synergistic effects of DL111-IT in combination with mifepristone (RU486) on termination of early pregnancy in rhesus monkeys. Pregnancy was confirmed by tactile sensation of pregnant uterus via anus with finger and ultrasound examination. Pregnancy termination was obtained with vaginal bleeding and abortion materials including fetuses and placentae after treatment. With multiple doses of DL111-IT or RU486 given alone between d24 and d50 of gestation, pregnancy arrests were obtained in 40% (2/5) of monkeys treated with DL111-IT intramuscularly (im) (25 mg x kg(-1) x d(-1) x 3 days), in 20% (1/5) of monkeys treated with 9 mg x kg(-1) x d(-1) x 2 days, and 4.5 mg x kg(-1) on day 3 with RU486 intragastrically (ig). DL111-IT (25 mg x kg(-1) on day 1, im) in combination with RU486 (the same treatment as above) resulted in 100% (10/10) termination of pregnancy and uterine bleeding lasted 6.6 +/- 1.3 days. RU486 (as above treatment) in combination with misoprostal (Miso, 109 microg x kg(-1) on day 3, ig) showed 71.4% (5/7) termination of pregnancy, and uterine bleeding lasted 12.9 +/- 9.6 days. The synergistic effect of DL111-IT plus RU486 enhances termination of early pregnancy and significantly shortens the bleeding time than RU486 plus Miso does in rhesus monkeys.

Medical abortion regimens: historical context and overview

Medical abortion offers an important alternative to surgical abortion for women with early pregnancies who wish to avoid a surgical procedure. More than 3 million women worldwide have had medical abortions in the past decade alone. The best-studied regimens include mifepristone orally followed 36 to 48 hours later by a prostaglandin analog administered either orally or intravaginally. Because of political and social restrictions related to mifepristone, however, researchers have investigated alternative regimens, most notably methotrexate and misoprostol. Mifepristone regimens are approximately 95% effective for abortion at </=49 days' gestation. Efficacy between 50 and 63 days' gestation varies according to the type and route of administration of the prostaglandin analog. Complete abortion rates among these later gestations are clinically acceptable when mifepristone is followed by intravaginally administered misoprostol or gemeprost. This report reviews the development, efficacy, and side effects of mifepristone regimens.

Termination of pregnancies of <6 weeks gestation with a single dose of 800 microg of vaginal misoprostol

This study evaluated the effectiveness of a single dose of the abortifacient effect of vaginal misoprostol followed by prolonged observation. Women with < or =42 days of amenorrhea, pregnancy confirmed by ultrasound, and approved request for termination received 800 microg of vaginal misoprostol once and were observed for 1 week. The gestational sac was measured before misoprostol administration, and 24 h and 7 days afterward. Women reported bleeding, expulsion of sac, and other complaints. After 1 week, those who had not aborted received a second dose of 800 microg. Those who had not aborted by 24 h later were treated by vacuum aspiration of the endometrial cavity. Twenty-four hours after treatment, 71.8% had aborted, and 87.1% aborted 3 days after treatment. After the second dose, 7 days later, the cumulative abortion rate reached 92.1%. None of the subjects who aborted required curettage or vacuum aspiration. The main complaints were pain (84.5%), nausea (21.4%), and headache (17.5%). No clinical differences between responders and nonresponders was found. Vaginal misoprostol, 800 microg, is effective in inducing early termination of pregnancy, and there is no need for an additional dose within 72 h after the first administration of misoprostol.

Safety, efficacy, and acceptability of medical abortion in China, Cuba, and India: a comparative trial of mifepristone-misoprostol versus surgical abortion

OBJECTIVE

We investigated safety, efficacy, and acceptability of an oral regimen of medical abortion compared with surgical abortion in three developing countries.

STUDY DESIGN

Women (n = 1373) with amenorrhea < or = 56 days chose either surgical abortion (as provided routinely) or 600 mg of mifepristone followed after 48 hours by 400 micrograms of misoprostol. This is the appropriate design for studying safety, efficacy, and acceptability among women selecting medical abortion over available surgical services.

RESULTS

The medical regimen had more side effects, particularly bleeding, than did surgical abortion but very few serious side effects. Failure rates for medical abortion, although low, exceeded those for surgical abortion: 8.6% versus 0.4% (China), 16.0% versus 4.0% (Cuba), and 5.2% versus 0% (India). Nearly half of failures among medical clients were not true drug failures, however, but surgical interventions not medically necessary (acceptability failures or misdiagnoses). Women were satisfied with either method, but more preferred medical abortion.

CONCLUSION

Medical abortion can be safe, efficacious, and acceptable in developing countries.

The efficacy and tolerance of mifepristone and prostaglandin in termination of pregnancy of less than 63 days gestation; UK Multicentre Study--final results

This paper summarizes the final results of an open multicenter study in 13 hospital gynecological units in Scotland and England. In the study, 1018 pregnant women with up to 9 week amenorrhoea received 600 mg oral mifepristone followed 48 h later by vaginal gemeprost 1 mg for the induction of first trimester abortion. Outcome was measured by assessment of the frequency of complete abortion or the need for subsequent surgical evacuation. Tolerance was assessed in terms of pain, requirement for analgesia, bleeding, and other adverse effects. There was complete abortion in 94.8% (95%CI 93.4-96.2); surgical evacuation was performed in 5.2% of patients. There was no relationship between outcome and age of gestation on the day mifepristone was given. Seven women were given a transfusion. Narcotic analgesia was administered after gemeprost to 38.1% of nullipara and 10.7% of multipara. Mifepristone and prostaglandin is an effective and acceptable alternative to surgical termination of pregnancy in the early first trimester.

Determination of RU486 (mifepristone) in blood by radioreceptorassay; a pharmacokinetic study

A human progesterone receptor assay has been developed for the measurement of the biologically active molecular fraction of RU486 (RU486 binding equivalent) for studying its pharmacokinetic properties. Thirty-nine healthy pregnant volunteers with amenorrhoea of 49 days or less receiving a single oral dose of 200 mg, 400 mg or 600 mg RU486 orally in a single dose were involved in this study. Blood samples were collected within 48 hours for the analysis. It was found that the pharmacokinetics of the RU486 binding equivalent followed an open two-compartment model. The dose was rapidly absorbed and peak serum concentrations were measured within 1-2 hours after ingestion of the drug. The distribution was also rapid, but the elimination was slow, the elimination half-life ranging between 83 and 90 hours. Significant differences were found between the peak plasma values for the 200 mg and 600 mg doses (p < 0.05) and between the AUCs for the 200 mg and 600 mg doses (p < 0.01) and the 400 mg and 600 mg doses (p < 0.05). It can be concluded that this newly developed radioreceptor assay satisfies the requirements of radioligand binding techniques and can be used to determine the serum levels of RU486 and its metabolites, which are able to bind to human myometrial progesterone receptors. The pharmacokinetics for the RU486 binding equivalent is similar to that for RU486, with the exception of very slow elimination, which may originate from the measurement of the biologically active metabolites together with the parent compound.

The use of misoprostol for termination of early pregnancy

Misoprostol is a prostaglandin analogue which has uterotonic properties. Administered vaginally, it is an effective agent for induction of second trimester abortions. This study was undertaken to determine if the vaginal administration of misoprostol is effective for inducing first trimester abortions. Fifty-eight women with pregnancies less than 10 weeks gestation who desired pregnancy termination received varying dosages of vaginal misoprostol, either alone or in combination with laminaria or tamoxifen. The overall success rate for a complete abortion was 61%. The use of laminaria or tamoxifen did not affect success rates. Abortions occurred within 24 hours of administration of misoprostol. Side effects were minimal. There were no significant differences in any of the following between those who had a successful abortion and those who did not: gravidity, parity, prior elective abortion, age, gestational age of the pregnancy, and level of human chorionic gonadotropin. Although not as successful as other combination regimens, misoprostol alone is readily available, easy to administer, and without major side effects. The use of this agent could eliminate the need for about two-thirds of surgical abortions in the first 10 weeks of gestation.

Termination of early pregnancy in the rat, rabbit, and hamster with RU 486 and anordrin

The effectiveness of oral RU 486 and anordrin given alone and in combination for terminating early pregnancy was tested in the rat, rabbit, and hamster. In the rat and rabbit, the combination of RU 486 and anordrin is more effective in terminating pregnancy than either of the two compounds used alone. A non-effective dose of RU 486 combined with a non-effective or a sub-effective dose of anordrin, or a low effective dose of RU 486 in combination with a non-effective dose of anordrin, exerted additive or synergistic effects resulting in resorption of embryos and termination of pregnancy in rats and rabbits. The serum progesterone as well as estradiol concentrations were significantly suppressed by these combinations when pregnancy was terminated. In the hamster, however, RU 486 was not effective in interrupting early pregnancy, even at a 4-fold higher dose than was effective in the rat, due to the fact that RU 486 does not bind to the progestin receptor in this species. Unexpectedly, there were also no effects of anordrin on pregnancy termination in the hamster even at high doses. It is concluded that in rat and rabbit, the synergistic action between RU 486 and anordrin not only greatly enhances efficacy in terminating pregnancy but also reduces substantially the doses required to produce this effect.

Potentiating effect of epostane on pregnancy terminating activity of RU 486 in the rat

The effectiveness of a combination of RU 486, an antiprogestin, and epostane, a 3 beta-hydroxysteroid dehydrogenase inhibitor, for termination of pregnancy in female rats was determined. Epostane administered at doses ranging from 8 to 48 mg/Kg/day on days 7, 8, and 9 of pregnancy did not influence the progress of the pregnancy. RU 486 in doses of 1, 2, and 4 mg/Kg/day terminated pregnancy in 0, 40, and 100% of rats, respectively. The combination of epostane (48 mg/Kg/day) plus RU 486 (1 and 2 mg/Kg/day) terminated pregnancy with complete resorption of fetuses in all treated animals. Unexpectedly, the drug combination that terminated pregnancy used a dose of epostane that was not highly effective in lowering serum progesterone levels when epostane was administered alone. Thus, in the rat, the synergistic action of epostane plus RU 486 may not be dependent upon reduced progesterone secretion plus receptor blockage as anticipated. The present results suggest that the combination of epostane plus RU 486 is effective for pregnancy termination.

Pregnancy termination with mifepristone and gemeprost: a multicenter comparison between repeated doses and a single dose of mifepristone. World Health Organization

OBJECTIVE

To compare two regimens of mifepristone plus gemeprost for early pregnancy termination.

DESIGN

A prospective, randomized, multicenter trial.

SETTING

Ten gynecological services, mostly in academic hospitals.

PARTICIPANTS

Three hundred eighty-five healthy women up to 35 years of age with amenorrhea less than or equal to 49 days requesting pregnancy termination.

TREATMENT

Mifepristone, 25 mg five times at 12-hour intervals (n = 192) or 600 mg as a single dose (n = 193) followed by 1 mg gemeprost 60 hours after the start of mifepristone.

MAIN OUTCOME MEASURES

Pregnancy outcome, time of onset and duration of vaginal bleeding, subjective complaints, and hormone changes during treatment and 6-week follow-up.

RESULTS

Treatment outcome was identical in both groups with an overall complete abortion rate of 92.7% among the 385 women included in the analysis. The frequency of complaints, bleeding patterns, and changes in hemoglobin, beta-human chorionic gonadotropin, estradiol, and progesterone were also similar in both groups. Cortisol (at 12 and 36 hours after mifepristone) and prolactin (at 12 hours) were significantly higher in the single 600-mg dose group.

CONCLUSION

When used for early pregnancy termination with prostaglandin, a lower dose of mifepristone than the currently recommended single 600-mg dose may suffice.

Future direction of abortion technology

Reliable statistical data indicate that even today abortion is widely used in the regulation of human reproduction, irrespective of whether it is well or badly tolerated. Medical responsibility therefore dictates that abortions should be made as safe as possible in order to safeguard the health of women who cannot avoid abortion. The most advanced development in abortion technology is medical abortion. At present, the best available method is the combination of an antiprogesterone (RU-486) and a low dose of prostaglandin, either in an injection (sulprostone) or in a vaginal pessary (gemeprost). The currently employed treatment schedules are still not optimal. The treatment lasts for at least 48 or 72 hours and close follow-up is needed to assess whether the treatment has been successful or not. The side-effects, however, are negligible, and the medical method is free from the complications of the surgical methods and those of anaesthesia. The high efficacy (95% complete abortion rate at a gestational age up to eight weeks) restricts the risk of surgery and anaesthesia to the 5% failures. Further research is required to develop a more appropriate treatment schedule, preferably a single-shot treatment. At the same time, the prevention of misuse of the medical methods must be guaranteed to achieve a better acceptance of these safe abortion methods by society. For the time being, medical supervision and follow-up seems to be mandatory, and a 'do-it-yourself' home method providing complete privacy must be regarded as unsafe and medically unacceptable.

The efficacy and tolerance of mifepristone and prostaglandin in first trimester termination of pregnancy. UK Multicentre Trial

OBJECTIVE

To investigate the use of oral mifepristone (RU 486) and vaginal gemeprost for the induction of legal first trimester abortion.

DESIGN

An uncontrolled multicentre observational study.

SETTING

13 Hospital gynaecological units in Scotland and England.

SUBJECTS

588 Pregnant women with up to nine weeks amenorrhoea having legal abortions.

INTERVENTIONS

Oral mifepristone 600 mg followed 48 h later by vaginal gemeprost 1 mg. Women stayed in the hospital for a minimum of 4 h on each occasion.

MAIN OUTCOME MEASURES

Frequency of complete abortion and the need for subsequent surgical evacuation, analgesia and blood transfusion.

RESULTS

There was complete abortion in 94% (95% CI 92-96%). None of the 46 women at less than 43 days gestation needed surgical evacuation. This was performed in 6.5% of the remainder but among these the rate did not increase with gestation. Five women (four from one centre) required both curettage and blood transfusion. A fall in haemoglobin concentration of 2-4 g/dl occurred in only 1%. Narcotic analgesia was required after gemeprost by 37% of nullipara and 13% of multipara. Overall 26% had vomiting and 13% diarrhoea.

CONCLUSION

The sequential use of oral mifepristone and vaginal gemeprost is effective in inducing abortion up to the 63rd day of pregnancy. Efficient management of pain and bleeding is easier if women are in a hospital for some hours after the gemeprost.

Predictors of failed attempted abortion with the antiprogestin mifepristone (RU 486)

The experience of 271 patients who received mifepristone (RU 486) in experimental protocols from July 1984 to January 1989 was analyzed by logistic regression methods. The regimen used was the strongest predictor of failure, followed by Quetelet's index and initial beta-human chorionic gonadotropin level. The relative risk of failure was 2.3 times with 7-day regimens and 6.3 times with the other regimens that obtained with regimens of 600 mg given once or twice. The relative risk of failure increased with increasing Quetelet's index; women in the top quartile were 2.9 times more likely to fail to abort than were women in the bottom quartile. The risk of failure increased with increasing initial beta-human chorionic gonadotropin level; those with an initial level greater than 19,800 mIU/ml were 2.8 times more likely to fail to abort than were women with an initial value less than or equal to 6350 mIU/ml. Body mass appears to influence the likelihood of abortion with mifepristone.

Antiprogesterone RU 486--a drug for non-surgical abortion

RU 486 is the first steroidal antiprogesterone in clinical use. It acts by binding to progesterone receptor, thus blocking the effects of progesterone at the uterine level, and provoking endometrial necrosis and shedding. RU 486 can, therefore, be used to interrupt early human pregnancy. In pregnancies of up to 7-8 weeks duration, the rate of complete abortions with RU 486 has ranged from 50% to 90%. The success rate can, however, be augmented up to 95%-100% by combining RU 486 with a low dose prostaglandin. RU 486 induced abortion has been well tolerated by women and highly acceptable to them. The bleeding starts 2-3 days after RU 486 administration lasting for 12-14 days. Possible clinical uses of RU 486 include induction of menstruation, late post-coital contraception, induction of labour after intrauterine fetal death, preoperative cervical ripening and treatment of progesterone receptor positive mammary tumours. When administered in the follicular phase of the cycle, RU 486 inhibits follicular development. In addition, the antiglucocorticoid properties of RU 486 have been used in symptomatic treatment of hypercortisolemia of Cushings disease. The pharmacokinetics of RU 486 are characterised by high micromolar serum concentrations, long half-life of 26-48 hours and substantial metabolism after oral administration. Although effective and well tolerated, RU 486 has aroused great moral controversy, which is currently hampering further testing and distribution of the drug. So far RU 486 has been accepted for termination of pregnancy in France and in the Peoples Republic of China, to be used with prostaglandins and under strict medical surveillance.

Voluntary interruption of pregnancy with mifepristone (RU 486) and a prostaglandin analogue. A large-scale French experience

In 2115 women seeking voluntary termination of pregnancy after 49 days of amenorrhea or less, we studied the effect of a single 600-mg dose of mifepristone (RU 486), followed 36 to 48 hours later by the administration of one of two prostaglandin analogues, either gemeprost (1 mg by vaginal suppository) or sulprostone (0.25, 0.375, or 0.5 mg by intramuscular injection). The women were monitored for four hours after prostaglandin administration. Efficacy was indicated by the complete expulsion of the conceptus without the need of an additional procedure. All other results were considered failures, and the pregnancy was then terminated by a surgical method. The overall efficacy rate was 96.0 percent (95 percent confidence interval, 95.0 to 96.8). The failures included persisting pregnancies (1.0 percent), incomplete expulsions (2.1 percent), and the need for hemostatic procedure (0.9 percent). The mean time to expulsion was significantly shorter when sulprostone was given in the high dose (4.5 hours) than when it was given in the two lower doses (13.1 and 19.3 hours) or when gemeprost was given (22.7 hours). The mean duration of uterine bleeding was 8.9 days (range, 1 to 35); one woman received a blood transfusion. Most women had transient abdominal pain after receiving prostaglandin, but there were few other side effects. We conclude that the administration of mifepristone followed by a small dose of a prostaglandin analogue is an effective and safe method for the early termination of pregnancy.

Progesterone antagonist lilopristone: a potent abortifacient in the common marmoset

The effects of a progesterone antagonist ZK 98.734 (lilopristone) on implantation, early pregnancy, and midpregnancy were studied in the common marmoset, Callithrix jacchus jacchus. Treatment (5 mg/da intramuscularly for 3 consecutive days) on day (n = 8) after the midcycle peak in estradiol levels in mated animals induced a premature drop in plasma progesterone levels and shortened the ovarian cycle length. Treatment on day 20 (n = 5) or day 40 (n = 5) induced a drop in progesterone levels and decidual collapse. In three animals treated on day 40, vaginal bleeding was observed within 46 hours of the initiation of treatment. Treatment on day 80 resulted in expulsion of the fetuses with a mean induction abortion interval of 39 hours (range, 20 to 48 hours). The progesterone antagonistic effects of ZK 98.734 could be a result of the decrease in progesterone synthesis by the corpus luteum and/or placenta in addition to the interference with the progesterone binding to its cellular receptors in the target organ. Our study suggests that ZK 98.734 has potential for fertility regulation. Clinical trials for postcoital contraception, induction of menstruation, and early abortifacient effects are warranted.

Pharmacokinetics of the antiprogesterone RU 486 in women during multiple dose administration

Serum levels of RU 486 were measured by high performance liquid chromatography (HPLC) following oral intake of 12.5, 25, 50 and 100 mg twice daily (b.i.d.) for 4 days, 50 mg b.i.d. for 7 days, as well as a single dose of 200 mg of RU 486. The pharmacokinetics of RU 486 were not linear: when the daily dose of RU 486 was 100 mg or more, the serum levels were similar. The pharmacokinetic behaviour of RU 486 during the treatment period was similar between the study subjects, whereas the elimination phase pharmacokinetics showed wide individual variation. Also the mean elimination phase half-lifes (t 12) of RU 486 varied from 25.5 to 47.8 h in the groups of different regimen, yet the variation between different groups was not statistically significant. The areas under the concentration curves (AUC) were calculated. In the multiple dose study (mds) the AUC0----12h:s decreased when the administered dose of RU 486 was increased. The AUC0----12h seen after administration of 100 mg b.i.d. x 4d. (mean +/- SEM = 0.43 +/- 0.04 mumol/l x h/mg) was significantly (P less than 0.05) lower than the AUC0----12h:s obtained with administration of 12.5 mg b.i.d. x 4d. (1.49 +/- 0.37 mumol/l x h/mg), 25 mg b.i.d. x 4d. (1.09 +/- 0.15 mumol/l x h/mg), and 50 mg b.i.d. x 7d. (0.72 +/- 0.11 mumol/l x h/mg). The AUC0----infinity obtained by administration of a single dose of 200 mg of RU 486 (sds) was 0.67 +/- 0.21 mumol/l x h/mg. It is concluded that if multiple dose administration of RU 486 is preferred, daily administration of relatively small doses of RU 486 over several days seem to be advantageous.

Prostaglandins and antiprogestins

There is considerable interest in the development of a non-surgical method to terminate early pregnancy. During the three weeks immediately following the first missed menstrual period, several prostaglandin (PG) analogs such as sulprostone, gemeprost and 9-methylene PGE2 have been used to terminate the pregnancy. Prostaglandins, however, at the doses required to induce disruption of the conceptus cause gastrointestinal side effects and uterine pain which are more severe than those subsequent to vacuum aspiration. Treatment with the antiprogestin, mifepristone counteracts the effects of progesterone in pregnancy and thus prevents maintenance of the pregnancy. Mifepristone administered alone causes termination of the pregnancy in most, but not all, cases. In addition to removing the influence of progesterone, mifepristrone also induces regular uterine contractions and significantly increased the sensitivity of the uterus to PG analogs. Mifepristone (50 mg/day) followed by an intramuscular injection of a low dose, (0.25 mg), of sulprostone (approximately 1/6 of the dose of prostaglandin necessary to induce abortion if used alone) was highly effective in terminating early pregnancy, causing complete abortion in 94% of cases. Gastrointestinal side effects were rare and uterine pain significantly less common than if PG analogs were used alone. Subsequently the combination of mifepristone and vaginal administration of gemeprost (0.5-1.0 mg) has been shown to be equally effective Ideally, the PG analog would be administered orally rather than by injection or vaginal administration. Preliminary data indicate that 9-methylene PGE2 but not PEG2 may be suitable for this purpose in combination with mifepristone.(ABSTRACT TRUNCATED AT 250 WORDS)

The antiprogestational agent RU 486 as an abortifacient in early human pregnancy: a comparison of three dose regimens

Three different regimens of RU 486, a progesterone receptor blocking agent, were compared for their ability to terminate early human pregnancy. One-hundred-fifty-three healthy women with a gestational length less than 49 days from the last menstrual period were recruited to the study and randomly allocated to one of three treatment regimens: 1) RU 486 10 mg x 2 for seven days; 2) RU 486 25 mg x 2 for seven days; or 3) RU 486 50 mg x 2 for seven days. No significant difference in efficacy was seen between the three dose regimens. Treatment with 10 mg x 2 x VII resulted in 73 per cent complete abortions, 25 mg x 2 x VII in 66 per cent and 50 mg x 2 x VII in 64 per cent complete abortions. Response to treatment, measured as reported onset of bleeding and passage of products of conception, however, occurred significantly later on the 10 mg x 2 regimen than on the other two dose regimens. In each treatment group, women who subsequently aborted completely had significantly lower pretreatment levels of hCG than women with incomplete abortion or continuing pregnancy. The treatment was well tolerated by the women and except for one woman who experienced a profound bleeding necessitating a blood transfusion, no serious side effects were seen.

Anti-progesterones for the interruption of pregnancy

Therapeutic abortion can be performed effectively and safely by vacuum aspiration of the uterus up to 12 weeks of amenorrhoea. Although the operative procedure could be regarded as simple, complications do occur and attempts have been made to develop non-surgical means of terminating pregnancy in the first 3-4 weeks following the first missed menstrual period. A variety of PG analogues have been developed which induce abortion in over 90% of women when given by vaginal pessary or intramuscular injections (see Bygdeman, 1984). In a large multicentre study (WHO, 1987) 0.5 mg sulprostone, administered three times with 3 h intervals, was recently found to be equally as effective as vacuum aspiration for termination of early pregnancy. The frequencies of complete abortion were 91 and 94%, respectively. However, the widespread acceptance of PG treatment is limited by a relatively high incidence of gastrointestinal side-effects and uterine pain. Treatment with antiprogesterones, both mifepristone and epostane, effectively induces abortion during early pregnancy, but the frequency of complete abortion is too low to be clinically acceptable. It remains to be demonstrated if other antiprogesterones such as ZK 98.734 and ZK 98.299, currently under development, may change this conclusion. Administration of mifepristone induces uterine contractions and increases the sensitivity of the myometrium to prostaglandins. These effects allowed the development of sequential treatment with a low dose of mifepristone and PG analogues administered vaginally or intramuscularly. The combined therapy has been shown to be highly effective (frequency of complete abortion between 95 and 100%) and is seemingly associated with a lower frequency of side-effects than if PG analogues are used alone. Whether this medical abortion method will be a realistic alternative to vacuum aspiration during the first 8 weeks of pregnancy depends on the outcome of further clinical trials, including randomized studies comparing the two procedures. It has been shown that mifepristone crosses the placenta (Frydman et al, 1985). An important factor which needs to be verified in future studies is therefore the possible embryotoxicity of this type of compound. The risk that pregnancy continues in spite of treatment can never be excluded.(ABSTRACT TRUNCATED AT 400 WORDS)

Pharmacodynamics of the antiprogesterone RU486 in women after oral administration

The pharmacokinetic characteristics of RU486 and its acute effects on anterior pituitary hormone secretion after oral administration were examined in six normal women. Serum RU486 concentrations were determined by a radioimmunoassay. The absorption of RU486 was rapid with peak serum levels reached approximately 90 minutes after a single oral dose (4 mg/kg). The disappearance of RU486 and its metabolites conformed to a noncompartmental model with a mean apparent half-life of 53.7 +/- 6.9 hours. The mean apparent volume of distribution and clearance rate were 1.47 +/- 0.25 l/kg and 1.04 +/- 0.09 1/hour, respectively. In comparison with a control group of normal women (n = 9), there were significant elevations in transverse mean cortisol levels in the RU486 group (P less than 0.01). However, mean adrenocorticotropic hormone (ACTH) levels and the diurnal pattern of ACTH and cortisol secretion were not changed. RU486 induced a mild prolactin (PRL) elevation (P less than 0.01), whereas thyroid-stimulating hormone (TSH) and luteinizing hormone (LH) levels were not altered. In view of the relatively slow clearance rate for RU486 and its metabolites, our findings suggest that the pharmacologic action of RU486 is prolonged after a single oral dose.

Early abortion with a single dose of the antiprogestin RU-486

RU-486 is a synthetic progesterone antagonist that is abortifacient in early pregnancy. This trial evaluated the effectiveness and safety of a single 600 mg oral dose given to 50 healthy women less than or equal to 49 days from their last menstrual period. Efficacy was inversely related to the initial beta-subunit of human chorionic gonadotropin level, ranging from 100% at less than 5000 mIU/ml to 81% at greater than 20,000 mIU/ml (p less than 0.05). Uterine bleeding was the most serious side effect. However, the mean change in the hemoglobin value 14 days after treatment was -0.4 gm/dl, and no patient required blood transfusion. This regimen appears to be simple, effective, and safe.

Early pregnancy termination with antiprogestins: a comparative clinical study of RU 486 given in two dose regimens and Epostane

Mifepristone, (RU 486, Roussel Uclaf, Romainville, France), a progesterone (P) receptor blocking agent, and Epostane, (WIN 32,729, Sterling-Winthrop, Guildford, United Kingdom), a P synthesis inhibitor, were compared for their ability to terminate early human pregnancy. Seventy-eight healthy women, with a gestational length of less than 49 days from the last menstrual period and who requested termination of pregnancy, were recruited to the study. The patients were randomly allocated to three treatment regimens: (1) Mifepristone 25 mg bid for 7 days; (2) Mifepristone 50 mg bid for 7 days; and (3) Epostane 200 mg qid for 7 days. The results of the study confirmed that both compounds are potent abortifacients in early human pregnancy. No difference in efficacy was seen between the two dose regimens of Mifepristone, which both resulted in 61% complete abortions. Seventy-three percent aborted completely in the Epostane group. Subjective side effects, especially nausea, were more common in the women treated with Epostane, but no serious side effects were seen.

Interception. III: Postcoital luteal contragestion by an antiprogestin (mifepristone, RU 486) in 62 women

The new antiprogestin mifepristone (RU 486) was studied as an emergency postcoital contragestive. An actual pregnancy rate of 1.6% was observed and was related to the actual conception rate. The follow-up rate was 100%. The patterns of onset and duration of the induced menstruation after mifepristone treatment are described. This method provides a good new interceptive technique when the time for use of postcoital steroids or for a postcoital IUD insertion has lapsed.

Termination of early gestation with the anti-progestin steroid RU 486: medium versus low dose

RU 486 is a synthetic steroid which has antiprogesterone and antiglucocorticoid activity. In order to determine the optimal dosage of this drug to terminate early pregnancy, we treated 106 healthy women with normal pregnancies by real time ultrasound examination whose gestational duration was less than 49 days from onset of last menses with either a medium or low dose treatment regimen. A total of 66 patients received the medium dose regimen (100 mg/day X 7 days). Another 10 patients received ergonovine (0.2 mg/day X 6 doses) on Day 4 of the same RU 486 treatment regimen. In the first group, 48 (73%) aborted successfully and, of the second group, 6 (60%) aborted. Eighty percent of the subjects in this group of 76 patients reported side effects of nausea and vomiting, heavy bleeding, severe menstrual cramps or headache. All these side effects were successfully treated with analgesic and antiemetic medication. The remaining 30 subjects were treated with a low dose regimen (50 mg/day X 7 days). Of these 30, 15 (50%) aborted; this incidence was significantly less (p less than 0.05). Following the medium dose treatment regimen, the AM cortisol levels were significantly elevated on treatment Days 4 and 8, as compared to baseline (p less than 0.001), although the mean levels were still within the normal range. With the low dose, there was a non-significant rise in AM cortisol values. Thus the rise in cortisol was significantly greater in the former group than the latter (p less than 0.05). With the medium dose regimen, the women who aborted had significantly lower (p less than 0.05) pretreatment mean B-HCG and progesterone levels than the group that failed to abort. Mean serum levels of RU 486 were not significantly different between the group who aborted and those who did not. RU 486 is a promising agent for termination of early pregnancy.