Termination of early pregnancy by ONO-802 suppositories (16,16-dimethyl-trans-delta2-PGE1 methyl ester)

Menstrual induction: surgery versus prostaglandins

In most developed countries in which therapeutic abortions are legal, termination of pregnancy is performed at between 8 and 12 weeks of gestation. Because the complication rate after this procedure rises with increasing gestation, there would be many advantages in inducing abortion before the eighth week ('menstrual induction'). With the increasing availability of highly sensitive methods of detecting human chorionic gonadotropin, pregnancy can now be diagnosed as early as 10-14 days after conception. The uterus can be surgically evacuated safely and simply by suction aspiration under local anaesthesia. However, a safe and effective method of inducing abortion by medical means would be a useful and cheaper alternative. Of the potentially useful compounds, only derivatives of prostaglandins E and F administered by vaginal pessary have so far been shown to be effective. Although the rate of haemorrhage and infection is low, 10-30% of women experience moderate side-effects of pelvic pain, diarrhoea and/or vomiting. The possibilities are discussed of reducing the incidence of side-effects by different methods of release or using prostaglandins in combination with other compounds such as antigestogens which might lower the therapeutic threshold.

Late second trimester abortion with 16,16-dimethyl-trans-delta 2-PGE1 methyl ester (gemeprost)

The use of gemeprost (16,16-dimethyl-trans-delta 2-PGE1 methyl ester) vaginal pessaries for the termination of pregnancy in the late second trimester has been investigated in an open single-center study. Of 56 nulliparous women between 18 and 22 weeks amenorrhoea, 33 (58.9%) aborted after the administration of 1 mg gemeprost pessaries; 5 women did abort after 3 doses, 10 after 4 doses and 18 after 5 doses. There was no statistical correlation between gestational age and abortion. The mean induction-abortion interval was 15.2 hrs (range 8.5-20.3 hrs). There were no serious complications. The safe induction of therapeutic abortion in 58.9% of women using vaginal gemeprost pessaries alone offers an acceptable alternative to surgical evacuation in the late second trimester but should not be started without the possibility to terminate the procedure by dilatation and evacuation (D + E).

Menstrual regulation by intramuscular injections of 16-phenoxy-tetranor PGE2 methyl sulfonylamide or vacuum aspiration. A randomized multicentre study. World Health Organization Task Force on Post-ovulatory Methods for Fertility Regulation

A multicentre trial was conducted to compare the efficacy and side-effects of an intramuscularly administered PGE2 analogue and vacuum aspiration in women with a delay of up to 21 days in the expected onset of menses. A total of 473 such women were randomly allocated to treatment with either 16-phenoxy-W-17, 18, 19, 20-tetranor PGE2 methyl sulfonylamide (three intramuscular injections of 0.5 mg at 3-h intervals) or vacuum aspiration, and the outcome of therapy assessed 1, 2 and 6-8 weeks later. Retrospective analysis of hCG levels indicated that 419 (88.6%) women had been pregnant at the time of treatment. With few exceptions, administration of the PGE2 analogue induced vaginal bleeding in both pregnant and non-pregnant women but the duration and subjectively perceived amount of bleeding were greater than after vacuum aspiration. Both treatments were equally effective. In pregnant women the overall frequency of complete abortion was 91% for prostaglandin treatment and 94% for vacuum aspirations. If non-pregnant women were included, the respective success rates (i.e. percentages of women not pregnant 2 weeks after treatment) were 92% and 95%. Gastrointestinal side-effects and lower abdominal pain requiring intramuscular analgesia were more common after prostaglandin therapy than following vacuum aspiration in both pregnant and non-pregnant women.

Serum relaxin concentrations in women following the administration of 16,16-dimethyl-trans-delta 2-PGE1 methyl ester during early pregnancy

Serum relaxin was estimated in 11 women during termination of first-trimester pregnancy with 16,16-dimethyl-trans-delta 2-PGE1 methyl ester (16 DM-PGE1). Vaginal administration of 16 DM-PGE1 was associated with a significant increase in serum relaxin.

Therapeutic abortion in early pregnancy with antiprogestogen RU486 alone or in combination with prostaglandin analogue (gemeprost)

Abortion was attempted in 39 women in early pregnancy (less than 56 days amenorrhea) with the progesterone antagonist RU486 alone (150 mg per day for 4 days) or in combination with a PG analogue, 16,16-dimethyl-trans-delta 2-PGE1 (Gemeprost) in the form of a 1 mg vaginal pessary. Complete abortion was also attempted in 5 women who received RU486 together with 2 X 1 mg PG pessaries. Vaginal bleeding followed by complete abortion occurred in 18 of 19 women who received RU486 + 1 mg PG pessary as compared to only 12 of 20 women who received RU486 alone (P less than 0.01). All women who received RU486 + 2 mg Gemeprost had a complete abortion. The onset of crampy abdominal pain (median: 3 vs 4 days) and vaginal bleeding (3 vs 3 days) was similar in the RU486 and RU486 + PG groups, respectively. Slightly less than half the patients in both groups had nausea and/or vomiting, but the incidence did not differ from that occurring prior to treatment. The mean duration (range) of vaginal bleeding [RU486 alone: 10 (0,29) days and RU486 + PG: (5,34) days], and the measured blood loss [RU486: 53 (2,227) ml and RU486 + PG: 81 (32,222) ml] did not differ significantly between the two treatments. It is concluded that the combination of RU486 and a single PG vaginal pessary is a highly effective means of inducing therapeutic abortion in early pregnancy and offers an alternative to surgery.

A controlled release form of 16,16-dimethyl-trans-delta 2-PGE, methyl ester for early abortion

The termination of early pregnancy (less than 56 days amenorrhoea) has been investigated using 16,16-dimethyl-trans-delta 2-PGE, methyl ester in a controlled release preparation. The onset of crampy abdominal pain was seen after 270 +/- 39 minutes and bleeding occurred after 603 +/- 95 minutes. Two (15%) patients required no pain relief during treatment, however 5 (38%) requested oral analgesia, and in 6 (46%) individuals the pain was severe enough to warrant parenteral opiates. The overall success rate for complete abortion was 85%. No serious adverse effects were seen, but vomiting occurred in 2 (15%) women, and diarrhoea in 3 (23%). Although the use of this prostaglandin analogue in slow release form provides an effective treatment method for early abortion using a reduced total dose of prostaglandin, the acceptability of the drug as an agent for menstrual induction continues to be limited by the occurrence of troublesome gastro-intestinal side effects.

Ectopic pregnancy among early abortion patients: does prostaglandin reduce the incidence?

The availability and efficacy of prostaglandin (PG) F2 alpha and E series analogues has prompted their frequent use for pregnancy interruption. In the course of evaluating our experience with PGs for interrupting early first trimester gestations, we became increasingly impressed by the absence of any with extrauterine pregnancy. A review of 63 reports encompassing 2,965 patients whose pregnancies were less than 8 weeks' gestational age dating from the last menstrual period and who were similarly treated yielded only 2 cases of ectopic pregnancy. When compared with the generally accepted ectopic gestation rates of the order of 1 in 200 pregnancies, this frequency of 1 in 1,483 is unexpectedly low. Preselection does not appear to explain this impressive discrepancy. If the observation proves correct, it implies that PGs have some form of therapeutic effect in eradicating extrauterine pregnancy by nonoperative means. The implications are obvious in terms of its potential therapeutic benefits.

The use of 16,16-dimethyl-trans delta 2 prostaglandin E1 methyl ester (gemeprost) vaginal pessaries for the termination of pregnancy in the early second trimester. A comparison with extra-amniotic prostaglandin E2

The use of gemeprost pessaries has been compared in an open randomized trial with the extra-amniotic infusion of prostaglandin E2 (PGE2) for the termination of pregnancy between 12 and 16 weeks gestation. The success rates were 77% and 79% for the pessary and infusion group respectively, and these rates were unaffected by parity. There was no significant difference in the cumulative abortion rate between the two groups, nor were there differences in the induction-abortion interval, nor in the time taken to the onset of pain or bleeding. However, women in the pessary group required significantly less analgesia than those in the infusion group. Side-effects, experienced both during treatment and during the 6 weeks after abortion, were similar in both groups. Gemeprost vaginal pessaries are an effective alternative to the extra-amniotic infusion of PGE2 for the termination of pregnancy in the early second trimester.

Menstrual regulation with prostaglandin (Pg ONO 802) in Indonesia

This study was conducted to evaluate the safety, efficacy and acceptability of PGE1 vaginal suppositories (Pg ONO 802) in menstrual regulation. Each vaginal suppository contains 1 mg of 16,16 dimethyl-trans-delta 2 PGE1 methyl ester. Five suppositories were inserted as high as possible into the fornix posterior of the vagina at intervals of 3 h. Five hundred thirty four subjects with delay of menses mostly of up to 14 days were included in the study. Blood chemistry was evaluated and urine analysis performed in all subjects. Success of treatment was assessed on two alternative groups of criteria: (A) induction of bleeding by Pg ONO 802; (B) induction of bleeding achieved by Pg ONO 802 and not followed by surgical intervention. The success rate based on criteria A was 98.9%, and on criteria B 86%. If heavy bleeding occurred and signs of pregnancy were found during the trial period, intervention was made by vacuum aspiration or curettage when necessary. If bleeding did not occur and/or pregnancy continued, treatment was declared a failure and pregnancy was terminated by vacuum extraction or curettage. For non-pregnant subjects no intervention was made but careful re-evaluation was carried out. Mean duration of bleeding after Pg ONO 802 treatment was 6.7 days. Side-effects were generally mild. The incidence of diarrhea was 8.8%, nausea 7.8%, headache 5.8%, vomiting 2.8%; abdominal cramp occurred in as many as 66% of subjects. No treatment was given for these side-effects as they were within acceptable limits.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortifacient effect and uterine cervix-dilating action of 16, 16-dimethyl trans delta 2 PGE1 methyl ester (ONO 802) in the form of a vaginal suppository (a randomized, double-blind, controlled study in the second trimester of pregnancy)

A newly synthesized 16, 16-dimethyl trans delta 2 PGE1 methyl ester (ONO 802) was clinically applied in the form of a vaginal suppository for therapeutic abortion of second trimester pregnancies. Its effects were studied in a double-blind test comparing it with an inactive placebo suppository. The study was conducted at 12 Japanese university hospitals. The number of patients was 125 in total, i.e. 63 receiving ONO 802 vaginal suppository (containing 1.0 mg ONO 802) and 62 receiving inactive placebo suppository. ONO 802 was more effective than placebo with a success rate of 87% (complete (71%) and incomplete (16%) abortions). The onset of uterine contractions was observed in 154.3+/-18.1 min. and the onset of uterine bleeding in 323.6+/-41.0 min. The expulsion of the fetus and placenta was observed in 955.4+/-97.0 and 961.6+/-97.0 min., respectively. The cervix dilating effect of ONO 802 was observed in 63.5% of the patients at 3 hours after the start of administration. Nausea, vomiting, abdominal cramps, diarrhea and pyrexia were noticed. However, all these side effects were transient and mild, requiring no treatment. No abnormality was observed in the puerperal course, duration of uterine bleeding or onset of subsequent menstruation following the therapeutic abortion. Therefore, the present study demonstrated that ONO 802 vaginal suppository was an effective and valuable drug for therapeutic abortion of second trimester pregnancies.

The abortifacient effect of 16,16-dimethyl-trans-delta 2-PGE1 methyl ester, a new prostaglandin analogue, on mid-trimester pregnancies and long-term follow-up observations

The present clinical trials revealed that 16,16-Dimethyl-trans-delta 2-PGE1 methyl ester in the form of vaginal suppositories is highly effective in inducing mid-trimester termination of pregnancies. It also showed that prior treatment with laminaria and metreurynter may enhance the success rate while reducing the incidence and severity of side effects. It is easy and safe to use clinically, with minimal side effects, and in our series, revealed no deleterious effects on ensuing reproductive physiology. However, the definite mechanism involved in the action of this new analogue to cause myometrial contractions is still not completely understood, and requires further intensive investigation.

The use of 16-16 dimethyl trans delta 2 PGE1 methyl ester (ONO 802) vaginal suppositories for the termination of early pregnancy. A comparative study

Vaginal suppositories containing the 16-16 dimethyl trans delta 2 PGE1 methyl ester (ONO 802) were used for the induction of abortion in early pregnancy, and this non-surgical technique was compared with suction termination performed under local anaesthesia or general anaesthesia. Ninety patients were recruited to the study and divided equally between the three groups. Complete abortion was induced in 87 per cent of the patients treated with ONO 802 suppositories, which compared favourably with 87 and 100 per cent for the patients who had suction terminations under local anaesthesia and general anaesthesia respectively. The vaginal suppositories induced uterine bleeding in all patients and the mean time of onset of lower abdominal pain was 2 hours 55 minutes. The average numbers of episodes of vomiting and diarrhoea for patients given ONO 802 suppositories were 0.9 and 0.7 respectively. Menstrual blood loss was measured objectively in all groups and no significant differences between the three methods could be found. In selected cases, ONO 802 vaginal suppositories would seem to be safe and reasonably effective for the termination of early pregnancy.