Oxytocin CAS 50-56-6

As we all know, oxytocin is the drug of choice for the prevention and treatment of postpartum hemorrhage, especially postpartum hemorrhage caused by uterine atony. “Where there is childbirth, there is oxytocin”, this is an indisputable fact. Almost all domestic and foreign guidelines list it as a first-line drug for postpartum hemorrhage. Oxytocin can be given intramuscularly or intravenously when it is used to prevent and treat postpartum hemorrhage. Prophylactic use of oxytocin before delivery of the placenta can reduce postpartum hemorrhage by 60%. For vaginal delivery, its dosage and administration methods are currently mostly standard 10U oxytocin uterine intramuscular injection or intravenous bolus injection.

For women undergoing elective cesarean section, WHO (2013) recommends a continuous intravenous infusion of oxytocin at 20 U/h, and the Royal College of Obstetricians and Gynaecologists (2012) recommends a slow intravenous bolus of 5 U. During cesarean section, lower doses of oxytocin (<5U/h) can maintain sufficient uterine contractility and significantly reduce hemodynamic changes. The protocol follows the “rules of threes” (3U oxytocin is injected slowly by intravenous bolus, and the interval is 3 minutes for evaluation. According to the evaluation results, it is decided whether to repeat the above process. It can be repeated 3 times in total, and finally the intravenous drip of 3U/h is carried out. maintenance, and prepare 3 alternative drugs to replace when oxytocin treatment is not effective). In high-risk women undergoing cesarean delivery, carbetocin (a long-acting oxytocin) can significantly reduce postpartum hemorrhage compared to oxytocin.

The Society of Obstetricians and Gynaecologists of Canada (SOGC, 2013) recommends that induction of labor at 41–42 weeks of gestation reduces perinatal mortality and meconium aspiration syndrome without increasing cesarean delivery rates. An important indicator of successful labor induction is the cervical ripening score (Bishop score). For those with immature cervix (Bishop score less than 4-6) who need to induce labor, it is best to promote cervical ripening before labor induction. It is generally believed that oxytocin is best used in the induction of labor for cervical ripening. The method of use is to add oxytocin 2.5U to 500ml of 5% glucose injection by intravenous drip for 6~8 hours, once a day, generally for 3 days.

It can be seen that oxytocin is worthy of further exploration in promoting cervical ripening. For those with mature cervix, if there is no contraindication, the induction of labor by intravenous infusion of oxytocin immediately after artificial rupture of the membrane can significantly shorten the labor process and reduce the rate of cesarean section. There are two different intravenous drip regimens for the use of oxytocin in labor induction: low-dose and high-dose. The low-dose regimen refers to the initial dose of 1-2 mU/min, and each adjustment is 1-2 mU/min, with an interval of 30 minutes. This regimen reduces rapid uterine contractions and their associated fetal heart rate abnormalities. The high-dose regimen refers to the initial dose of 4-6 mU/min, each adjustment is 4-6 mU/min, and the interval is 15-30 min. This regimen has a shorter labor process and less chorioamnionitis and cesarean section due to dystocia. labor, but increased rapid uterine contractions and their associated fetal heart rate abnormalities.

The key to the use of oxytocin for oxytocin in the first stage of labor is to detect and correctly assess uterine atony in time, so as to obtain the timing and sufficient time limit for oxytocin to enhance productivity; in the second stage of labor, oxytocin oxytocin still needs to be Clear indications, avoid obstructive dystocia and threatened uterine rupture. The current research results show that there is no difference between the aforementioned high-dose and low-dose intravenous oxytocin oxytocin regimens, but there are many clinical cases of uterine rupture due to excessive injection of oxytocin in the second stage of labor. Therefore, when good uterine contractions and labor progress are obtained, the dose of oxytocin should be reduced or discontinued after entering the active phase, and the natural production process should be pursued. Oxytocin is not suitable for intramuscular injection, acupoint injection or submucosal administration during labor induction, because these administration methods vary from person to person, and the sensitive dose of oxytocin is not well controlled. rupture.

When it comes to commonly used drugs to terminate pregnancy (commonly known as “drug abortion”), the most likely ones that come to mind are mifepristone and misoprostol. The sensitivity of uterine muscle to oxytocin is related to gestational age. It gradually increases with the increase of gestational age at 20-30 weeks of gestation, and reaches the highest level at 34 weeks, and then maintains this level to full-term pregnancy. Therefore, oxytocin is not commonly used to terminate pregnancy during pregnancy. Family planning (SFP, 2011) guidelines for induction of labor in the second trimester indicate that high-dose oxytocin is an option when prostanoids are deficient or contraindicated. Compared with mifepristone and misoprostol, oxytocin to terminate pregnancy has fewer adverse reactions, and oxytocin can be used to terminate pregnancy for pregnant women who are not suitable for miso and mifepristone.

This is mainly applied to the oxytocin challenge test for our prenatal monitoring, which is still commonly used in clinical practice. Oxytocin challenge test (OCT) can be performed in those with suspected placental insufficiency after excluding third trimester bleeding, multiple pregnancy, poly or oligohydramnios, threatened preterm labor, premature rupture of membranes, and scarred uterus. ). The specific method is: intravenous infusion of oxytocin 2.5U into 500ml of 5% glucose injection, the initial drip rate is 5 drops/min, and the drip rate is adjusted every 15min to reach the effective uterine contraction intensity, that is, 3 times every 10min Uterine contractions, each lasting 40 to 60 s, were monitored for 40 min to record fetal heart rate and uterine contraction curve. The combined NST+OCT trial helps to reduce perinatal asphyxia and mortality without increasing the incidence of fetal distress and neonatal asphyxia.

Oxytocin is a polypeptide substance, its main function is to strengthen uterine contractions, and it can also promote the contraction of smooth muscle cells around the mammary alveoli, which is conducive to the discharge of milk. Oxytocin nasal spray can promote early postpartum lactation and increase milk production. The specific usage is to spray one spray on each nostril of the puerpera immediately after giving birth, and then use it 2-3 minutes before each breastfeeding, one spray on each nostril, and use it continuously for 7 days.

This usage is also more common in clinical practice. For retrograde abortion/hysterectomy patients, we ask nurses to establish venous access for them before they enter the operating room. For patients with hydatidiform mole, when uterine evacuation is planned, because the patient’s uterus is large and soft, there is often more bleeding or even shock during uterine evacuation. In order to reduce bleeding, oxytocin can be added to the infusion after fully dilating the cervix and starting to suck the uterus. Add 5-10 U of oxytocin to each 500ml solution to strengthen uterine contractions and reduce bleeding, and can also prevent the hydatidiform mole from squeezing into the uterus. Sinus.

The application of oxytocin in obstetrics and gynecology-related diseases is roughly the same. At present, the clinical application of oxytocin in the treatment of endometriosis and uterine fibroids is still in the research stage, so I won’t mention it here. Now, let’s look at the application of oxytocin in non-gynecological fields.