Effects of misoprostol on human circulation

How do I perform cell salvage in obstetrics?

Maternal mortality in the United States is increasing. The leading cause of death is hemorrhage. Maternal hemorrhage can be profound, with entire blood volumes being lost. In most major blood loss surgery, autotranfusion (also known as cell salvage, cell saving, and intraoperative blood collection and readministration) is a technique that has been used to minimize allogeneic transfusion. Historically, autotransfusion has been considered contraindicated in the face of maternal hemorrhage because of a fear of incorporating amniotic fluid in the salvaged blood. Recent data suggests that this fear is unfounded, with several medical societies now recommending that autotransfusion be used during maternal hemorrhage. In this review, autotransfusion during maternal hemorrhage is discussed, and suggestions are made for how to make it most successful.

Effects of oxytocin and anaesthesia on vascular tone in pregnant women: a randomised double-blind placebo-controlled study using non-invasive pulse wave analysis

BACKGROUND

Oxytocin is an uterotonic drug with profound cardiovascular effects, which in compromised patients could lead to serious events. The objective was to investigate whether oxytocin affects cardiac function and vascular tone in large and small arteries. We hypothesized that oxytocin decreases arterial vascular tone and elevates cardiac output.

METHODS

51 pregnant women were randomised to treatment with 8.3 μg (5 U) oxytocin or placebo injection during first trimester surgical evacuation of the gravid uterus under general anaesthesia. Oxytocin or placebo was administered once either early or late in the procedure, in a double-blind fashion. Digital photoplethysmography pulse wave analysis variables, heart rate, mean arterial blood pressure and electrocardiographic ST index were recorded before and after anaesthesia and after each injection. Non-parametric statistics were used with a two-sided P value < 0.05 considered significant.

RESULTS

Anaesthesia induced a significant fall in blood pressure, heart rate and vascular tone in small and peripheral arteries. Oxytocin had a vasodilatory effect on small and peripheral arteries and increased the left cardiac ventricular ejection time. The ST index decreased.

CONCLUSIONS

Pulse wave analysis indicated peripheral vasodilation and increased cardiac output after oxytocin, implying increased myocardial oxygen demand. These effects might have been enhanced by the vasodilating effects of anaesthesia. Previous studies have demonstrated myocardial ischaemia after oxytocin, as reflected by a decrease in ST index in the present study.

TRIAL REGISTRATION

Trial registration number ISRCTN17860978 , 2018/03/14, Retrospectively registered.

Prostaglandin E2 inhibits mast cell-dependent bronchoconstriction in human small airways through the E prostanoid subtype 2 receptor

BACKGROUND

Inhaled prostaglandin (PG) E2 might inhibit asthmatic responses, but the mechanisms involved remain undefined.

OBJECTIVE

We sought to characterize the direct and indirect effects of PGE2 on human small airways with particular reference to the receptors mediating the responses.

METHODS

Contraction and relaxation were studied in isolated human bronchi with an inner diameter of 1 mm or less.

RESULTS

Low concentrations of PGE2 (0.01-1 μmol/L) relaxed the bronchi precontracted by histamine. The bronchodilator response was inhibited by the E prostanoid (EP) subtype 4 receptor antagonist ONO-AE3-208 but unaffected by the EP2 receptor antagonist PF-04418948. Higher concentrations of PGE2 (10-100 μmol/L) contracted the small airways. However, the TP receptor agonists U-46,619, PGF2α, and PGD2 were more potent than PGE2. Moreover, the bronchoconstrictor responses to PGE2 and all other tested prostanoids, including the EP1/EP3 receptor agonist 17-phenyl trinor PGE2 and the partial FP receptor agonist AL-8810, were uniformly abolished by the TP receptor antagonist SQ-29,548. In the presence of TP and EP4 antagonists, PGE2 inhibited the mast cell-mediated bronchoconstriction resulting from anti-IgE challenge. Measurement of the release of histamine and cysteinyl leukotrienes documented that this bronchoprotective action of PGE2 was mediated by the EP2 receptor, unrelated to bronchodilation, and increased with time of exposure.

CONCLUSION

The pharmacology of PGE2 in isolated human small airways was different from its profile in animal models. This first demonstration of powerful EP2 receptor-mediated inhibition of IgE-dependent contractions in human airways introduces a new selective target for the treatment of asthma. This EP2 control of mast cell-mediated bronchoconstriction is presumably exaggerated in patients with aspirin-exacerbated respiratory disease.

Postpartum misoprostol for preventing maternal mortality and morbidity

BACKGROUND

The primary objective of postpartum haemorrhage (PPH) prevention and treatment is to reduce maternal deaths. Misoprostol has the major public health advantage over injectable medication that it can more easily be distributed at community level. Because misoprostol might have adverse effects unrelated to blood loss which might impact on mortality or severe morbidity, it is important to continue surveillance of all relevant evidence from randomised trials. This is particularly important as misoprostol is being introduced on a large scale for PPH prevention in low-income countries, and is commonly used for PPH treatment in well-resourced settings as well.

OBJECTIVES

To review maternal deaths and severe morbidity in all randomised trials of misoprostol for prevention or treatment of PPH.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (11 January 2013).

SELECTION CRITERIA

We included randomised trials including pregnant women who received misoprostol in the postpartum period, versus placebo/no treatment or other uterotonics for prevention or treatment of PPH, and reporting on maternal death, severe morbidity or pyrexia.We planned to include cluster- and quasi-randomised trials in the analysis, as a very large number of women will be needed to obtain robust estimates of maternal mortality but we did not identify any for this version of the review. In future updates of this review we will include trials reported only as abstracts if sufficient information is available from the abstract or from the authors.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and extracted data.

MAIN RESULTS

We included 78 studies (59,216 women) and excluded 34 studies.There was no statistically significant difference in maternal mortality for misoprostol compared with control groups overall (31 studies; 11/19,715 versus 4/20,076 deaths; risk ratio (RR) 2.08, 95% confidence interval (CI) 0.82 to 5.28); or for the trials of misoprostol versus placebo: 10 studies, 6/4626 versus 1/4707 ; RR 2.70; 95% CI 0.72 to 10.11; or for misoprostol versus other uterotonics: 21 studies, 5/15,089 versus 3/15,369 (19/100,000); RR 1.54; 95% CI 0.40 to 5.92. All 11 deaths in the misoprostol arms occurred in studies of misoprostol ≥ 600 µg.There was a statistically significant difference in the composite outcome 'maternal death or severe morbidity' for the comparison of misoprostol versus placebo (12 studies; average RR 1.70, 95% CI 1.02 to 2.81; Tau² = 0.00, I² = 0%) but not for the comparison of misoprostol versus other uterotonics (17 studies; average RR 1.50, 95% CI 0.50 to 4.52; Tau² = 1.81, I² = 69%). When we excluded hyperpyrexia from the composite outcome in exploratory analyses, there was no significant difference in either of these comparisons.Pyrexia > 38°C was increased with misoprostol compared with controls (56 studies, 2776/25,647 (10.8%) versus 614/26,800 (2.3%); average RR 3.97, 95% CI 3.13 to 5.04; Tau² = 0.47, I² = 80%). The effect was greater for trials using misoprostol 600 µg or more (27 studies; 2197/17,864 (12.3%) versus 422/18,161 (2.3%); average RR 4.64; 95% CI 3.33 to 6.46; Tau² = 0.51, I² = 86%) than for those using misoprostol 400 µg or less (31 studies; 525/6751 (7.8%) versus 185/7668 (2.4%); average RR 3.07; 95% CI 2.25 to 4.18; Tau² = 0.29, I² = 58%).

AUTHORS' CONCLUSIONS

Misoprostol does not appear to increase or reduce severe morbidity (excluding hyperpyrexia) when used to prevent or treat PPH. Misoprostol did not increase or decrease maternal mortality. However, misoprostol is associated with an increased risk of pyrexia, particularly in dosages of 600 µg or more. Given that misoprostol is used prophylactically in very large numbers of healthy women, the greatest emphasis should be placed on limiting adverse effects. In this context, the findings of this review support the use of the lowest effective dose. As for any new medication being used on a large scale, continued vigilance for adverse effects is essential and there is a need for large randomised trials to further elucidate both the relative effectiveness and the risks of various dosages of misoprostol.

Misoprostol and dinoprostone therapy for labor induction: a Doppler comparison of uterine and fetal hemodynamic effects

OBJECTIVE

To compare the effect of misoprostol (PGE(1)) versus dinoprostone (PGE(2)) on blood flow in uteroplacental circulation during labor induction.

STUDY DESIGN

Eighty-four women with indications for induction of labor were assigned to receive either misoprostol 50 microg per vagina every 4 h as needed or 0.5 mg doses of dinoprostone given intra-cervically every 6 h by means of a randomization table generated by computer. Doppler velocimetry of umbilical, uterine and arcuate arteries was performed immediately before and 2-3 h after the administration of misoprostol or dinoprostone. The SAS system was used to perform statistical analysis.

RESULTS

There were no significant changes of pulsatility index (PI), resistance index (RI) and systolic/diastolic (S/D) ratio in umbilical arteries after both prostaglandin compounds. Vaginal application of misoprostol significantly increased all ratios in arcuate artery and S/D ratio in uterine artery. Intra-cervically dinoprostone significantly increased PI, RI and S/D ratio in arcuate and uterine arteries.

CONCLUSIONS

Our results indicate that vaginal misoprostol and cervical dinoprostone administration increases uteroplacental resistance but does not affect umbilical blood flow. Misoprostol would be as safe and effective agent as dinoprostone for cervical ripening and labor induction.

A randomized, controlled trial comparing effect of oral misoprostol and intravenous syntocinon on intra-operative blood loss during cesarean section

BACKGROUND

Oxytocics are routinely used in an attempt to prevent excessive blood loss during cesarean section. Misoprostol, a potent uterotonic agent, has been reported to be useful in the prevention and treatment of postpartum hemorrhage by several investigators but its use during cesarean section has not been described. The objective of this study was to randomly compare the effectiveness of oral misoprostol with intravenous syntocinon on blood loss during elective cesarean sections under regional anesthesia.

METHODS

Sixty pregnant women were randomized either to receive misoprostol 400 micrograms orally or syntocinon 10 IU intravenously during cesarean section. The primary outcome measure was intra-operative blood loss as estimated by physicians, and by values of preoperative and postoperative hemoglobin concentration and hematocrit. Demographic characteristics of the subjects and outcomes were compared using chi-square test for categorical and two-sample t-test for continuous data.

RESULTS

Baseline characteristics in terms of age, body weight, parity, gestational age and indications for cesarean section were similar in both groups. The estimated blood loss was 545 ml (CI 476-614) in misoprostol group and 533 ml (CI 427-639) in syntocinon group (p = 0.85). Differences in preoperative and postoperative hemoglobin and hematocrit values were also similar in both groups. Two women in the misoprostol group and three in the syntocinon group (p=0.64) required additional oxytocics. One patient in each group required blood transfusion. No serious side effects were noted in either group.

CONCLUSION

Oral misoprostol appears to be safe and as effective as intravenous syntocinon in reduction of intra-operative blood loss during elective cesarean section under regional anesthesia and merits further investigation.

Misoprostol therapeutics revisited

Misoprostol, a prostaglandin E1 analog, is a racemate of four stereoisomers. On administration it rapidly de-esterifies to its active form, misoprostolic acid. Misoprostolic acid is 85% albumin bound and has a half-life of approximately 30 minutes. It is excreted in urine as inactive metabolites. No significant drug interactions have been reported. Besides its gastrointestinal protective and uterotonic activities, misoprostol regulates various immunologic cascades. It inhibits platelet-activating factor and leukocyte adherence, and modulates adhesion molecule expression. It protects against gut irradiation injury, experimental gastric cancer, enteropathy, and constipation. It improves nutrient absorption in cystic fibrosis. Misoprostol has utility in acetaminophen and ethanol hepatotoxicity, hepatitis, and fibrosis. It is effective in asthmatics and aspirin-sensitive asthmatic and allergic patients. It lowers cholesterol and severity of peripheral vascular diseases, prolongs survival of cardiac and kidney transplantation, synergizes cyclosporine, and protects against cyclosporine-induced renal damage. It works against drug-induced renal damage, interstitial cystitis, lupus nephritis, and hepatorenal syndrome. It is useful in periodontal disease and dental repair. Misoprostol enhances glycosoaminoglycan synthesis in cartilage after injury. It prevents ultraviolet-induced cataracts and reduces intraocular pressure in glaucoma and ocular hypertension. It synergizes antiinflammatory and analgesic effects of diclofenac or colchicine and has been administered to treat trigeminal neuralgic pain. It reduces chemotherapy-induced hair loss and recovery time from burn injury, and is effective in treating sepsis, multiple sclerosis, and pancreatitis.

Cardiovascular effects of intravaginal misoprostol in the mid trimester of pregnancy

OBJECTIVE

Our aim was to evaluate the cardiovascular effects of high-dose intravaginal misoprostol administration by means of transthoracic electrical bioimpedance monitoring.

STUDY DESIGN

Healthy women undergoing mid trimester pregnancy interruption with intravaginal misoprostol were eligible for this prospective observational study. Baseline blood pressure was obtained for 1 hour and transthoracic electrical bioimpedance monitoring was performed before misoprostol administration, 600 microg vaginally. Posttreatment assessments were made every 15 minutes for a total of 4 hours, with patients in a left lateral recumbent position. Heart rate, mean arterial pressure, cardiac index, stroke index, systemic vascular resistance index, and end-diastolic volume index were determined. Measurements were averaged for 30-minute intervals and reported as mean +/- SD. Statistical analyses included the paired t test and repeated-measures analysis of variance.

RESULTS

Nine women consented to have transthoracic electrical bioimpedance monitoring, and no statistically significant changes in any of the measured cardiac parameters for the 4-hour monitoring interval were noted. Direct comparisons between the pretreatment and 2-hour posttreatment intervals (reported time peak of blood misoprostol levels) also revealed no significant differences in the cardiovascular index values.

CONCLUSION

High-dose intravaginal misoprostol in the mid trimester does not alter maternal cardiac function as measured by transthoracic electrical bioimpedance.

The misoprostol third stage of labour study: a randomised controlled comparison between orally administered misoprostol and standard management

OBJECTIVE

To compare misoprostol with standard oxytocic regimens in the prevention of postpartum haemorrhage.

DESIGN

Randomised controlled trial.

SETTING

Obstetric unit in a large teaching hospital.

METHODS

One thousand women randomised to 500 microg misoprostol given orally or to standard oxytocic regimens of oxytocin, oxytocin with ergometrine, or ergometrine.

MAIN OUTCOME MEASURES

Incidence of postpartum haemorrhage and the incidence and severity of side effects.

RESULTS

Postpartum haemorrhage occurred in 12% of women given misoprostol and in 11% of women given standard oxytocic drugs (relative risk (RR) 1.10, 95% confidence interval (CI) 0.79, 1.55). Blood loss of 1000 mL or more occurred in 2% of women in each group. Nausea, headache, dizziness and tiredness were less frequent with misoprostol (RR (95% CI) 0.71 (0.59, 0.84); 0.53 (0.38, 0.74); 0.73 (0.61, 0.87) and 0.88 (0.83, 0.94) respectively). The main side effects of misoprostol were shivering (RR 1.95, 95% CI 1.69, 2.25) and a rise in temperature (difference in mean rise 0.34 degrees C, 95% CI 0.26, 0.42).

CONCLUSION

Oral misoprostol for the prevention of postpartum haemorrhage was comparable to standard oxytocics. Many side effects were less common with misoprostol but shivering and pyrexia were more common. Larger randomised trials are needed before establishing the equivalence between misoprostol and standard oxytocic drugs in the prevention of postpartum haemorrhage.

Misoprostol compared with methylergometrine for the prevention of postpartum haemorrhage: a double-blind randomised trial

OBJECTIVE

To compare the efficacy and side effects of misoprostol, compared with methylergometrine, for the prevention of postpartum haemorrhage.

DESIGN

A double-blind, randomised clinical trial of 200 women with apparently normal pregnancies.

SETTING

University teaching hospital.

PARTICIPANTS

Two hundred women with apparently normal pregnancies.

METHODS

After the baby had been born, all women received two capsules by mouth and the contents of an ampule by intravenous injection. Each woman only received one active product. The capsules contained either a total of 600 microg misoprostol or placebo, and the ampule 200 microg of methylergometrine or placebo.

MAIN OUTCOME MEASURES

Need for further oxytocic drugs, blood pressure, the presence of side effects, mean haemoglobin and haematocrit three days after delivery.

RESULTS

Two hundred women completed the study (100 received methylergometrine and 100 misoprostol). Postpartum haemorrhage occurred in 4.3% of the methylergometrine group and 8.3% of the misoprostol group (P = 0.57). The need for further oxytocic drugs was 4.4% and 12.8% after methylergometrine and misoprostol, respectively (P = 0.065). One hour after the birth of the baby there was no difference in the mean systolic blood pressure (117 +/- 12 mmHg versus 115 +/- 11 mmHg) (P = 0.26) or the mean diastolic blood pressure (72 +/- 10 mmHg versus 71 +/- 11 mmHg for the groups receiving methylergometrine or misoprostol, respectively) (P = 0.97). The mean temperature in the misoprostol group rose to 37.4 degrees C, compared with 37 degrees C in the methylergometrine group (P < 0.0001). In the misoprostol group 34% developed fever (> 38 degrees C) compared with 3% in the methylergometrine group (P < 0.0001). Shivering (visual analogue score > or = 8) also occurred more often after misoprostol (42%) than after methylergometrine (8.5%) (P < 0.0001). The haemoglobin level (g/dL) on the third postpartum day was similar for both groups ( 11.0 and 11.2 for methylergometrine and misoprostol, respectively) (P = 0.39).

CONCLUSIONS

This study suggests that although protection from postpartum haemorrhage using parenteral methylergometrine and oral misoprostol is nearly equal, misoprostol is associated with more side effects.

Rectal misoprostol in the prevention of postpartum hemorrhage: a placebo-controlled trial

OBJECTIVE

This study investigated the effectiveness of rectal misoprostol in preventing postpartum hemorrhage.

STUDY DESIGN

In a randomized, placebo-controlled study, 550 women were randomly allocated to rectally receive 400 microg misoprostol or nonidentical placebo after normal vaginal delivery. Any excessive bleeding was actively managed with conventional oxytocic agents. Blood loss was measured directly.

RESULTS

The baseline variables were similar. Blood loss of > or = 1000 mL occurred in 4.8% (13/270) of the misoprostol group and 7% (19/272) of the placebo group. Additional oxytocic therapy was required by 3.3% and 4.7%, respectively. No predominance of side effects, particularly shivering, was noted in the misoprostol group.

CONCLUSIONS

Postpartum use of 400 microg rectal misoprostol was well tolerated and associated with a statistically nonsignificant trend toward less postpartum hemorrhage. The early active management of excessive bleeding with conventional oxytocic agents may have reduced the potential of the study to detect differences between the groups.

Use of oral misoprostol in the prevention of postpartum haemorrhage

OBJECTIVE

To investigate the use of the oral prostaglandin E1 analogue, misoprostol in the prevention of postpartum haemorrhage.

DESIGN

A prospective observational study.

SETTING

A university teaching hospital.

PARTICIPANTS

Two hundred and thirty-seven consecutive women undergoing vaginal delivery.

METHODS

All the women were given 600 micrograms oral misoprostol just after delivery.

MAIN OUTCOME MEASURES

Rates of postpartum haemorrhage; need for therapeutic oxytocic drugs; retained placenta and length of the third stage of labour.

RESULTS

Postpartum haemorrhage occurred in 6% of the women; the need for therapeutic oxytocics in 5%, retained placenta in 2% and the median length of the third stage was 5 min. Vomiting and diarrhoea in the first hour after delivery occurred in 8% and 3% respectively and shivering in 60%.

CONCLUSIONS

Misoprostol may be effective in the prevention of postpartum haemorrhage, and has few side effects. A double blind randomised trial is required.

Misoprostol: new frontiers; benefits beyond the gastrointestinal tract

Recent findings suggest that the protective role that misoprostol exerts in the gastrointestinal tract against nonsteroidal anti-inflammatory drug (NSAID) damage may be extended to a variety of other tissues and other noxious stimuli including those mediated by molecules such as interleukin 1 (IL-1), tumor necrosis factor (TNF), and endotoxin. The protective effects of misoprostol outside the gastrointestinal tract may involve prevention of triggering activities that would otherwise initiate a sequence of tissue damaging events. If this capacity of misoprostol to maintain homeostasis in a variety of settings is recognized, a cohesive pattern of action emerges. Numerous studies have shown that misoprostol is likely to act as a regulator within various cascades of immunological regulatory events. The in vitro and in vivo experimental data described in this paper suggest that the events which trigger episodes of pain and inflammation may be controllable by the administration of misoprostol. Mitigation of adverse effects of certain NSAIDs on renal function and cartilage metabolism has also been observed. Demonstration of this latter phenomenon in the clinical setting will greatly benefit the patient if it is shown to modify the arthritis disease process. The therapeutic applications of misoprostol beyond the gastrointestinal tract appear to be among the most interesting of therapeutic advances offered by any class of compound in the next decade. Because of the inflammatory and pain processes associated with arthritis disease progression, particular emphasis and confirmation through further clinical study should be placed on the potential effect of misoprostol on chondroprotection and synergy with NSAIDs.

Misoprostol: a prostaglandin E1 analog with antisecretory and cytoprotective properties

Misoprostol, a methylester analog of prostaglandin E1, with antisecretory and cytoprotective properties, has undergone extensive investigation and has received Food and Drug Administration approval for the prevention of nonsteroidal-induced ulceration. The drug represents the first synthetic, orally active prostaglandin evaluated for the treatment of peptic ulcer disease. Clinical studies reveal a trend toward slightly lower healing rates with misoprostol when compared with histamine (H2)-receptor antagonists in the treatment of gastric and duodenal ulcers. In addition, misoprostol was less effective than H2-blockers in reducing ulcer pain, and caused a higher incidence of adverse reactions, particularly diarrhea occurring in up to 13 percent of the patients treated. Several studies have shown misoprostol to be superior to cimetidine and sucralfate in the prevention of alcohol- and drug-induced gastritis. This report summarizes the biopharmaceutics, pharmacokinetics, and clinical efficacy of misoprostol in the treatment of gastric and duodenal ulcers and in the prevention of mucosal injury.