The pharmacokinetics and different regimens of misoprostol in early first-trimester medical abortion

The chemical geographies of misoprostol: Spatializing abortion access from the biochemical to the global

C22W38O5 is a chemical that travels. Better known as misoprostol, it was designed as a stomach ulcer drug but is now used around the world as an abortion pill due to the self-experimentation of Latin American communities who were seeking ways to end unwanted pregnancies. We develop a chemical geography approach to misoprostol that allows us to scale inward to understand the chemical properties of this medication while also being able to scale out to understand how medicinal effects are interwoven with and determined by global politics. Misoprostol as a chemical alone does not guarantee a successful abortion and instead 'scaffolding' in the form of mobility and information is required to transform misoprostol from a chemical to a safe and effective technology of abortion. First, we examine how misoprostol is moved by feminist networks in Mexico and Peru. Second, we argue that in order to be useful it is not enough just to access the pills, information on how to use them is required. These themes culminate in our contribution of 'pharmacokinetical geographies'; the micro-geography of the placement of pharmaceuticals in and on a body and its ramifications. The chemical geographies of misoprostol tell a story of power, bodily autonomy, and resistance.

Medication Abortion Safety and Effectiveness With Misoprostol Alone

Importance

Misoprostol-alone regimens for abortion may be more effective than previously thought.

Objective

To estimate the effectiveness of medication abortion with misoprostol alone among individuals self-managing their abortion.

Design, Setting, and Participants

For this prospective observational cohort study of callers to safe abortion hotlines and accompaniment groups in Argentina, Nigeria, and Southeast Asia, participants were recruited between July 31, 2019, and October 1, 2020, prior to starting their medication abortion. Eligible participants were 13 years or older, had no contraindications to medication abortion, and were not currently bleeding. Participants completed a baseline and 2 follow-up surveys. The analysis was restricted to participants who reported using misoprostol alone and was performed between January 6, 2022 and September 8, 2023.

Exposure

Self-managed medication abortion using misoprostol alone.

Main Outcomes and Measures

The primary outcome was effectiveness, defined as participant self-report of complete abortion without procedural intervention, measured at 1 week and 3 weeks after taking misoprostol. Secondary outcomes included method safety, measured by self-report of experiencing warning signs (eg, heavy bleeding, pain, fever, discharge) indicative of a potential complication and by medical treatment (eg, blood transfusion, intravenous fluids, overnight hospital stay) indicative of a potential adverse event. Additional outcomes included length of bleeding and cramping, time to expulsion, and experience of adverse effects.

Results

Among 1352 enrolled participants, 637 used misoprostol-alone regimens for abortion and were included in the analysis (591 [92.8%] from Nigeria, 45 [7.1%] from Southeast Asia, and 1 [0.2%] from Argentina; 384 [60.2%] aged 20-29 years; 317 [49.8%] with pregnancy durations <7 weeks and 205 [32.2%] with pregnancy durations between 7 and <9 weeks). At last follow-up after taking medication (median, 22 days; IQR, 21-26 days), 625 participants (98.1%; 95% CI, 96.7%-98.9%) had a complete abortion without procedural intervention. Potential adverse events were reported by 6 participants (0.9%; 95% CI, 0.4%-2.1%). Most participants experienced bleeding for less than 1 week (median, 4 days; IQR, 3-6 days) and expelled their pregnancy within 24 hours of starting the abortion process (median, 12 hours; IQR, 9-15 hours). Common side effects included nausea (335 participants [52.6%]), fever (232 [36.4%]), and diarrhea (181 [28.4%]).

Conclusions and Relevance

The findings suggest that misoprostol alone is a highly effective method of pregnancy termination. Future research should explore strategies to maximize the effectiveness of misoprostol alone in clinical and nonclinical settings.

Determination of misoprostol acid in plasma samples by UPLC-MS/MS with application in a maternal-fetal pharmacokinetic study following a low misoprostol dose vaginally to induce labor

Misoprostol is a prostaglandin E1 synthetic analogous used for elective interruptions of early pregnancy, treatment of incomplete abortion, postpartum hemorrhage and induction of full-term labor. Its a lipophilic drug, passing by extensive and rapid pre-systemic metabolism into the active metabolite, misoprostol acid (MA). The objective of this study was to develop and validate a highly sensitive method for MA determination in plasma using UPLC-MSMS, with application in a study of maternal-fetal pharmacokinetics in healthy parturients women (n = 10) after administration of 25 μg misoprostol vaginally. The method presented linearity of 2-10 pg/mL and acceptable precision, accuracy, plasma and solution stability. The parturients women presented median (interquartile range) values of AUC^0-6 of 68.0 (40.8-84.7) pg.h/mL, C_max of 21.9 (11.9-30.1) pg/mL and T_max of 2.25 (0.69-5.00) h. The placental transfer of MA was assessed from the umbilical vein/maternal blood ratios of 1.40 (0.91-2.13) and intervillous space/maternal blood ratios of 0.49 (0.15-3.41). In conclusion, this method presented high sensitivity, being able to quantify MA in plasma samples following a low 25 μg misoprostol administered vaginally aimed to induce labor in parturients women. Additionally, this is the first description of the placental transfer of MA after a vaginal administration of misoprostol.

A Relative Bioavailability Study of Two Misoprostol Formulations Following a Single Oral or Sublingual Administration

Introduction

Misoprostol (Cytotec) was primarily made for treating gastric ulcers. However today it is mostly used for abortion, treating postpartum hemorrhage, and for induction of labor. The tablet contains 200 µg of misoprostol, yet the dosages used for induction of labor are much smaller (25–50 µg), leading to uncertainty of dosage in daily use.

Aim

To evaluate and compare the relative bioavailability of two misoprostol products (Angusta 25 µg and Cytotec 200 µg tablets) administered orally or sublingually given in a daily clinical setting to women admitted for induction of labor at term.

Methods

Women carrying a live, singleton fetus in a cephalic position and with a gestational age between 259 and 296 days were included. Blood samples were collected at 0, 5, 10, 20, 30, 40, 50, 75, 100, 120, 180, and 240 minutes. A serum analytical assay was performed and pharmacokinetic parameters were calculated. Patients were assigned to one of three groups.

Results

A total of 72 patients were included. No significant differences demographic characteristics were found. The ratios for AUC, AUC (_0−t), and C_max were similar in all three groups, but CI-values were outside the required 80–125%. Sublingual administration yielded a 20–30% higher bioavailability and a 50% higher C_max than compared to the oral route.

Conclusion

The relative bioavailability between Angusta and Cytotec could not be confirmed as being equal at the 25 µg or 50 µg level because the 90% CI-values when comparing the ratios for AUC, AUC_(0−t), and C_max were wider than accepted. The reason for this could be the real-life, non-standardized circumstances in which the study was conducted. Sublingual administration seems to have higher bioavailability than oral administration. More studies are needed to ascertain an optimal dosage regime balancing both safety and efficacy for mother and child.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT02516631.

A prospective observational study of the follow-up of medical management of early pregnancy failure

BACKGROUND

Medical termination for missed miscarriage with the use of 800 μg of vaginal misoprostol as a single agent is recommended as a cheap option before 14 weeks of gestation in developing countries. A few studies have looked at its efficacy.

METHODS

A prospective, observational study was done on women having medical termination with up to three doses of 800 μg vaginal misoprostol at 12 hourly intervals. The number of women who needed check curettage was collected. Ultrasound findings if done were collated. Follow-up was done telephonically at the end of first week, fourth week and sixth week.

RESULTS

The cohort comprised 145 women. The primary outcome was the need for curettage after expulsion of products following medical management and this was 49/145 (37.8%) of women. The induction expulsion interval was 36 hours. The mean endometrial thickness of the 113/145 women who had an ultrasound was 11 mm. The mean endometrial thickness in women who had check curettage was 18 mm. Persistent spotting was the only significant symptom at follow-up. Resumption of cycle at the end of the sixth week was seen in 105/132 (80.15%) of women who were followed up.

CONCLUSION

Findings of our study showed the check curettage rate of 37.8%. However, the regime which we used, that is, 800 μg vaginal misoprostol at 12 hourly intervals had a long induction to expulsion interval of 36 hours. In all, 80% of women resumed normal cycles at the end of the sixth week. No significant complications were noted on follow-up.

Efficacy and safety of administering oral misoprostol by titration compared to vaginal misoprostol and dinoprostone for cervical ripening and induction of labour: study protocol for a randomised clinical trial

Background

Among the various methods available, the administration of prostaglandins is the most effective for inducing labour in women with an unfavourable cervix. Recent studies have compared treatment with various titrated doses of oral misoprostol with vaginal misoprostol or dinoprostone, indicating that the use of an escalating dose of an oral misoprostol solution is associated with a lower rate of caesarean sections and a better safety profile. The objective of this study is to assess which of these three therapeutic options (oral or vaginal misoprostol or vaginal dinoprostone) achieves the highest rate of vaginal delivery within the first 24 h of drug administration.

Methods

An open-label randomised controlled trial will be conducted in Araba University Hospital (Spain). Women at ≥41 weeks of pregnancy requiring elective induction of labour who meet the selection criteria will be randomly allocated to one of three groups: 1) vaginal dinoprostone (delivered via a controlled-release vaginal insert containing 10 mg of dinoprostone, for up to 24 h); 2) vaginal misoprostol (25 μg of vaginal misoprostol every 4 h up to a maximum of 24 h); and 3) oral misoprostol (titrated doses of 20 to 60 μg of misoprostol following a 3 h on + 1 h off regimen up to a maximum of 24 h). Both intention-to-treat analysis and per-protocol analysis will be performed.

Discussion

The proposed study seeks to gather evidence on which of these three therapeutic options achieves the highest rate of vaginal delivery with the best safety profile, to enable obstetricians to use the most effective and safe option for their patients.

Trial registration

NCT02902653 Available at: https://clinicaltrials.gov/show/NCT02902653 (7th September 2016).

Electronic supplementary material

The online version of this article (10.1186/s12884-018-2132-3) contains supplementary material, which is available to authorized users.

Rectal vs. sublingual misoprostol before cesarean section: double-blind, three-arm, randomized clinical trial

PURPOSE

The commonest surgical procedure for women is cesarean delivery. Postpartum hemorrhage and intra-operative blood during cesarean delivery is a major concern to all obstetricians. This study was conducted to assess the efficacy of the adjuvant use of misoprostol and oxytocin in decreasing intra-operative blood loss in cesarean delivery.

METHODS

This was a double-blinded randomized clinical trial including 636 term pregnant woman scheduled for cesarean section at Ain Shams University Maternity Hospital, Cairo, Egypt, between February 2013 and February 2014. Participants received either 400-μg misoprostol rectally or sublingually or placebo before cesarean section together with 5-IU oxytocin IV. The main outcome measure was intra-operative blood loss. Difference between the three groups was analyzed using one-way ANOVA test (for numeric variables) and Chi-square test (for categorical variables). P < 0.05 was considered statistically significant.

RESULTS

Intra-operative blood loss was higher in patients who did not receive misoprostol (Placebo Group) (295-1075 ml, 641.7 ± 135.7) than those who received it, regardless the route of administration, rectal (135-830 ml, 457.5 ± 140.7; P < 0.001), and sublingual (135-680 ml, 357.8 ± 129.7; P < 0.001). In addition, sublingual route was associated with significantly lower estimated intra-operative blood loss compared to rectal administration (P < 0.001).

CONCLUSIONS

Misoprostol with oxytocin is an effective drug-combination for decreasing intra-operative blood loss during cesarian section with clinical superiority to sublingual over rectal route.

Different Routes of Misoprostol for Same-Day Cervical Priming Prior to Operative Hysteroscopy: A Randomized Blinded Trial

STUDY OBJECTIVE

To compare the effectiveness of and patient satisfaction with different routes of misoprostol administration for short-term cervical priming before operative hysteroscopy.

DESIGN

Randomized blinded trial (Canadian Task Force classification I).

SETTING

University hospital.

PATIENTS

One hundred and twenty patients undergoing operative hysteroscopy.

INTERVENTIONS

Patients were randomly assigned to receive 400 μg of misoprostol administered orally (n = 40), vaginally (n = 40), or sublingually (n = 40) for cervical priming at 1.5 to 4 hours before undergoing operative hysteroscopy.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was preoperative cervical dilatation. Secondary outcomes included cervical consistency, ease of dilation and time of dilation, patient discomfort, and side effects. No differences were noted among the 3 groups in terms of patient age, parity, previous vaginal delivery, menopausal status, and time interval from preparation to procedure. Patients in the 3 groups reported similar discomfort and side effects. Initial mean cervical dilatation was 6.1 ± 2.0 mm in the oral group, 6.4 ± 2.1 in the vaginal group, and 6.4 ± 1.8 mm in the sublingual group (p = .75). Cervical consistency and ease of dilation were similar among the groups. The mean time of dilation was 37.2 ± 30.6 seconds in the oral group, 31.7 ± 29.0 seconds in the vaginal group, and 31.5 ± 21.7 seconds in the sublingual group (p = .59). Additional subanalyses according to menopausal status and parity did not demonstrate any differences among the groups.

CONCLUSION

Same-day cervical priming for operative hysteroscopy is achieved equally with all routes of misoprostol administration, with similar patient satisfaction and side effects.

The Effect of Combined Oxytocin-Misoprostol Versus Oxytocin and Misoprostol Alone in Reducing Blood Loss at Cesarean Delivery: A Prospective Randomized Double-Blind Study

PURPOSE

To compare the effect of combined oxytocin-misoprostol versus oxytocin and misoprostol alone in reducing blood loss at cesarean delivery.

METHODS

One hundred fifty patients of 18-40 years with singleton term pregnancies scheduled for cesarean section under spinal anesthesia were recruited in a prospective double-blind randomized clinical trial to one of the three following groups to receive 20 IU infusion of oxytocin (group O), 400-µg sublingual misoprostol tablets (group M) or 200-µg misoprostol plus 5 IU bolus intravenous oxytocin (group MO) after delivery. The hemoglobin level before surgery and 24 h after surgery, the need for additional oxytocic therapy, and the incidence of adverse effects were recorded.

RESULTS

The mean blood loss during surgery was significantly lower in group MO compared to other groups (P = 0.04). Comparison of mean arterial pressure (P = 0.38) and heart rate (P = 0.23) changes during spinal anesthesia and surgery failed to reveal any statistically significant differences between all groups through repeated measure analysis.

CONCLUSION

The use of combined lower dose of misoprostol-oxytocin significantly reduced the amount of blood loss during and after the lower segment cesarean section compared to higher dose of oxytocin and misoprostol alone, and its use was not associated with any serious side effects.

[First experience of the use of misoprostol as post-abortion care in Libreville, Gabon]

Introduction

Une étude a été menée afin de déterminer le taux d'acceptabilité de 400µg de misoprostol par voie sublinguale comme traitement de première intention de l'avortement incomplet et de préciser le taux d'avortement complet ou vacuité utérine.

Méthodes

Les femmes éligibles avaient un diagnostic clinique d'avortement incomplet avec une taille utérine inférieure à celle d'un utérus de 12 semaines d'aménorrhées (SA). Chacune a reçu 400µg de misoprostol par voie sublinguale. Les femmes ont été revues après une semaine. A J7, celles qui n'avaient pas complètement expulsé ont eu le choix entre une nouvelle consultation de suivi à J14 et la pratique d'une évacuation chirurgicale immédiate.

Résultats

145 patientes ont été éligibles et ont toutes accepté la méthode (100%). L’âge moyen était de 25,9 ± 6 ans. A J7, 120 patientes étaient guéries (85,7%). A J14, le taux de réussitea été de 95,7% soit 134 patientes guéries. Les patientes guéries ont déclaré être très satisfaites (57,5%), satisfaites (41,8%) et insatisfaite (0,7%). Au total,128 femmes (95,5%) ont dit être prêtes à utiliser de nouveau le misoprostol comme méthode d’évacuation utérine en cas d'avortement incomplet.

Conclusion

L’étude démontre que le 400µg misoprostol par voie sublinguale nous permet de prendre en charge d'une manière adéquate l'avortement incomplet surtout dans les pays à faible ressource et notamment dans les structures sanitaires de première ligne ou éloignées.

Prevention of postpartum haemorrhage with sublingual misoprostol or oxytocin: a double-blind randomised controlled trial

OBJECTIVE

Sublingual misoprostol produces a rapid peak concentration, and is more effective than oral administration. We compared the postpartum measured blood loss with 400 μg powdered sublingual misoprostol and after standard care using 10 iu intramuscular (IM) oxytocin.

DESIGN

Double-blind randomised controlled trial.

SETTING

A teaching hospital: J N Medical College, Belgaum, India.

SAMPLE

A cohort of 652 consenting eligible pregnant women admitted to the labour room.

METHODS

Subjects were assigned to receive the study medications and placebos within 1 minute of clamping and cutting the cord by computer-generated randomisation. Chi-square and bootstrapped Student's t-tests were used to test categorical and continuous outcomes, respectively.

MAIN OUTCOME MEASURES

Measured mean postpartum blood loss and haemorrhage (PPH, loss ≥ 500 ml), >10% pre- to post-partum decline in haemoglobin, and reported side effects.

RESULTS

The mean blood loss with sublingual misoprostol was 192 ± 124 ml (n=321) and 366 ± 136 ml with oxytocin IM (n=331, P ≤ 0.001). The incidence of PPH was 3.1% with misoprostol and 9.1% with oxytocin (P=0.002). No woman lost ≥ 1000 ml of blood. We observed that 9.7% and 45.6% of women experienced a haemoglobin decline of >10% after receiving misoprostol and oxytocin, respectively (P ≤ 0.001). Side effects were significantly greater in the misoprostol group than in the oxytocin group.

CONCLUSION

Unlike other studies, this trial found sublingual misoprostol more effective than intramuscular oxytocin in reducing PPH, with only transient side effects being greater in the misoprostol group. The sublingual mode and/or powdered formulation may increase the effectiveness of misoprostol, and render it superior to injectable oxytocin for the prevention of PPH. Further research is needed to confirm these results.

Sublingual misoprostol for first trimester termination of pregnancy

OBJECTIVES

To compare blood loss, efficiency, and acceptability of repeated doses of sublingual misoprostol with the standard Tunisian regimen of mifepristone-misoprostol for first trimester medical abortion.

METHODS

A prospective randomized trial of 252 healthy pregnant women requesting medical abortion in the first trimester (up to 56 days). Participants were randomized to receive 200mg of oral mifepristone followed by 400 microg of oral misoprostol (group 1) or 800 microg of sublingual misoprostol repeated every 4 hours for up to a maximum of 3 doses (group 2). Primary outcome was blood loss assessed by decrease in hematocrit.

RESULTS

Mean decrease in hematocrit at follow-up was significantly greater in group 1 than in group 2 (3.65%+/-1.18% vs 2.69%+/-1.89%, respectively; P=0.02). There was no difference in efficiency rates between groups 1 and 2 (94.5% vs 92.1%; P=0.7). Comparable proportions of women experiencing at least one adverse effect after misoprostol administration were reported in groups 1 and 2 (81.7% vs 79.4%; P=0.75).

CONCLUSION

Compared with the most widely used regimen in Tunisia (mifepristone-misoprostol), sublingual misoprostol alone induces less blood loss (although not clinically significant); it is less expensive and offers reduced interval time to expulsion.

A randomized controlled trial comparing powdery sublingual misoprostol and sublingual misoprostol tablet for management of embryonic death or anembryonic pregnancy

OBJECTIVES

To compare complete abortion rate, duration of abortion, and side effects between 600 microg powdery sublingual misoprostol and 600 microg sublingual misoprostol tablet for management of embryonic death or anembryonic pregnancy.

MATERIALS AND METHODS

Fifty-four pregnant women up to 13 weeks of gestation diagnosed with embryonic death or anembryonic pregnancy were randomized to receive 600 microg powdery sublingual misoprostol or 600 microg sublingual misoprostol tablet. Complete abortion was evaluated by transvaginal ultrasound at 48 h.

RESULTS

Twenty-six patients received 600 microg powdery sublingual misoprostol and 28 patients received 600 microg sublingual misoprostol tablet. Complete abortion rate was 34.6% in powdery sublingual misoprostol group and 32.1% in sublingual misoprostol tablet group (P = 0.847). Duration of abortion in powdery sublingual misoprostol group and sublingual misoprostol tablet group was similar (34.7 +/- 18.8 vs. 36.9 +/- 17.8 h, respectively, P = 0.656). There was no significant difference in the side effects between both groups.

CONCLUSIONS

Single dose of 600 microg of powdery sublingual misoprostol does not improve its efficacy for management of embryonic death or anembryonic pregnancy when compared to sublingual misoprostol tablet.

[Misoprostol for treating postpartum hemorrhages]

Postpartum hemorrhage is defined by bleeding > 500 mL through the vagina. It is one of the obstetrical complications that obstetricians fear most. It is the leading cause of maternal mortality in the world, especially in developing countries. The reference treatments in France are parenteral oxytocin and sulprostone. Sulprostone involves sometimes fatal side effects, and must be administered only in appropriate health care facilities. It also has the major disadvantage of requiring refrigeration. Misoprostol has uterotonic properties that have led to its occasional off-label use in the treatment of postpartum hemorrhage, by rectal or sublingual administration, as an alternative to sulprostone. A careful review of the literature on this particular use of misoprostol is essential.

Update on medication abortion

This article provides an overview of medication abortion in the United States 6 years after the approval of mifepristone (RU486; Mifeprex; Danco Laboratories, LLC, New York, NY) by the US Food and Drug Administration (FDA). The adoption of mifepristone is considered in the context of epidemiologic data on abortion, abortion access, and the safety of abortion. The risks of medication and aspiration abortion are discussed in the context of abortion-related mortality, recent experience with obstetric and gynecologic infection with Clostridium sordellii, and the limits of scientific knowledge on the incidence of this infection in women. Innovative protocols studied since FDA approval of mifepristone are presented, and implications for clinical practice are discussed.