What is Misoprostol?
Misoprostol is an active ingredient used for the treatment of Cervical Ripening, Dilation of the cervix and induction of labour in women with an unfavourable cervix.
The brand name of Misoprostol in the United States is Cytotec.
Mechanism of action (MOA) of Misoprostol, gynecology
It induces contraction of the uterine musculature, acts as a blood vessel dilating agent and as a mild bronchodilator on the bronchial smooth muscle fiber.
It also acts on the gastrointestinal tract by inhibiting acid secretion acting directly on gastric parietal cells, decreasing pepsin production, stimulating duodenal bicarbonate secretion and increasing gastric mucus production.
Therapeutic indications of Misoprostol, gynecology
Cervical ripening and induction of term labour, especially in cases of immature cervix provided there are no fetal or maternal contraindications (25 mcg).
Dilation of the cervix of the non-pregnant uterus prior to hysteroscopy or other gynecological procedures requiring access to the uterine cavity (200 mcg).
Vaginal release system 200 mcg: induction of labour in women with an unfavourable cervix, from the 36th week of pregnancy, where induction is clinically indicated.
Dosage of Misoprostol, gynecology
– Cervical ripening and induction of term labour, especially in cases of immature cervix provided there are no foetal or maternal contraindications: 25 mcg at 4-6 h intervals, up to a maximum of 100-150 mcg.
– Dilatation of the cervix of the non-pregnant uterus prior to hysteroscopy or other gynaecological procedures requiring access to the uterine cavity: 400 mcg 2 to 8 hours before, in uteruses with no history of previous caesarean section or uterine scarring and 2 to 4 hours before, in uteruses with a history of previous caesarean section or uterine scarring.
Vaginal release system:
–Induction of labour in women with an unfavourable cervix, from the 36th week of pregnancy, where induction is clinically indicated: controlled release system that releases misoprostol at a rate of approximately 7 mcg/h for 24 hours. Maximum dose is one vaginal release system (200 mcg).
Mode of administration of Misoprostol, gynecology
Vaginal release system:
Administered by staff with obstetrics expertise in a hospital where means are available to enable continuous fetal and uterine monitoring.
The condition of the cervix will be carefully evaluated before using Misodel.
After insertion, uterine activity and fetal condition will be monitored regularly.
Contraindications of Misoprostol, gynecology
Hypersensitivity to misoprostol, prostaglandins.
When oxytocic drugs are contraindicated or prolonged contractions of the uterus are considered inappropriate
Cervical ripening and induction of term labour:
History of cesarean section or major uterine surgery; cephalopelvic disproportion.
Suspicion or clinical evidence of pre-existing fetal distress; history of difficult and/or traumatic delivery.
Multiparous women with 6 or more previous term pregnancies; transverse fetal situations.
Obstetric emergencies when the risk-benefit ratio for both fetus and mother warrants surgical intervention. Multiple pregnancies.
Unexplained vaginal discharge and/or irregular uterine bleeding during the current pregnancy.
Patients in whom vaginal delivery is not indicated, such as with placenta previa or active genital herpes; concomitance of oxytocin and other stimulants of uterine contractions.
Risk factors for amniotic fluid embolism, severe pre-eclampsia or eclampsia.
Induction of labor in women with unfavorable cervix, from the 36th week of gestation:
When labour has begun.
If there is suspicion or evidence of fetal distress prior to induction (e.g., unsuccessful or failed stress test, meconium staining of amniotic fluid, or diagnosis or history of non-reassuring fetal condition).
When there is suspicion or evidence of uterine scarring resulting from previous uterine or cervical surgery, for example, cesarean delivery.
If there is a uterine abnormality (e.g. bicornate uterus).
When there is placenta previa or vaginal bleeding of unknown cause after 24 weeks of gestation in the present pregnancy.
If there is poor fetal position.
When there are signs and symptoms of chorioamnionitis, unless adequate pre-treatment has been instituted: before 36 weeks of gestation.
Warnings and precautions with Misoprostol, gynecology
- Epilepsy or history of epilepsy.
- Kidney and/or liver disease;
- Cardiovascular disease.
- History of cesarean section or major uterine surgery.
- Haemostatic disorders accompanied by hypocoagulability or anaemia.
- Ruptured chorioamnion membranes.
- Chorioamnionitis (infection of the placental membranes and amniotic fluid), hydatidiform mole and intrauterine fetal death.
- Not recommended in: kidney failure, liver failure, malnutrition.
- Increased risk of postpartum disseminated intravascular coagulation in patients who have been induced to give birth by a physiological or pharmacological method.
Vaginal release system:
Misoprostol may cause excessive uterine tachycystole that may not respond to treatment with tocolytics.
Closely monitor to ensure removal of the vaginal delivery system immediately at the start of labor or if uterine contractions are prolonged or excessive or if there is a clinical complication in the mother or baby.
Misoprostol is used for induction of labor at term, at low doses for a short period of time. When used at this time of pregnancy there is no risk of fetal malformation. However, it should not be used at any other time in pregnancy. A three-fold increased risk of fetal malformations (including Moebius syndrome, amniotic band syndrome, and central nervous system abnormalities) has already been reported in pregnancies exposed to misoprostol during the first trimester.
Interactions of Misoprostol, Gynecology
- Power effect of: oxytocin.
- Inhibition of the anticoagulant effect of: acenocumarol.
- Potentiation of toxicity at a neurological level with: phenylbutazone, naproxen and abdominal pain or diarrhea (diclofenac, indomethacin).
- Increases frequency and intensity of diarrhea with: antacids.
- Administration of laxatives: intense diarrhea.
Pregnancy and Misoprostol, Gynecology
Breastfeeding and Misoprostol, gynecology
It is excreted in breast milk, but its concentration is negligible within 5 hours of administration.
Side effects and adverse reactions of Misoprostol, gynecology
Vaginal tablets: nausea, vomiting, diarrhea and abdominal pain.
Vaginal Release System: Fetal heart rate disorder; abnormal delivery affecting the fetus, meconium in the amniotic fluid, abnormal uterine contractions.
Source: The content of this active ingredient has been written taking into account the clinical and molecular information of all medicines authorised and marketed in the United States under the Unique Ingredient Identifier (UNII) by the Substance Registration System (SRS) of the Food and Drug Administration (FDA) and the United States Pharmacopeia (USP).
In order to know in detail the information authorized by the FDA for each drug, you should consult the corresponding medication guide authorized by the FDA.