Uterine contraction drugs

The uterus is an important reproductive organ for women. After giving birth, the mother's uterus cannot contract immediately, so her belly still looks relatively large. If the uterus does not contract for a long time, it will have a great impact on women, so female friends need to take some drugs that can promote uterine contraction. Below, I will introduce to you several uterine contraction drugs that are more common in clinical medicine.

1. Oxytocin

This product is extracted from the neurohypophysis (posterior pituitary) of pigs, cattle and sheep, and can also be artificially synthesized. Their potency is expressed in units, with 1 unit equivalent to 2 g of pure oxytocin.

Process in the body: It is well absorbed after intramuscular injection, with onset of action within 3-5 minutes and duration of action for 20-30 minutes. Can be absorbed through the nasal cavity. Most of it is destroyed by the liver, and a small part is excreted unchanged in the urine.

Pharmacological action: It has been proven that there are oxytocin receptors in uterine smooth muscle and mammary gland. Oxytocin causes uterine contraction and promotes milk ejection by binding to the receptors. The receptor density in the non-pregnant uterus is low, while the number of receptors in the pregnant uterus gradually increases, reaching its peak in the late pregnancy, and the number of receptors in the uterine body is significantly higher than that in the cervix. Adverse reactions:

2. Posterior pituitary hormone

This product is a crude preparation extracted from the neurohypophysis of pigs, cattle, sheep and other animals, containing equal amounts of oxytocin and vasopressin (antidiuretic hormone).

Oxytocin in posterior pituitary hormone has the effects of stimulating labor, inducing labor or stopping bleeding after delivery. Due to its complex composition, including vasopressin, it is not very selective for uterine smooth muscle and has many adverse reactions. Therefore, it has been replaced by oxytocin as a uterine contraction drug. The vasopressin contained in posterior pituitary hormone has two effects: 1. By binding to the corresponding receptors on the renal collecting ducts, it increases the reabsorption of water and has a significant antidiuretic effect, which can be used to treat diabetes insipidus; 2. It acts on vascular smooth muscle, constricts blood vessels, especially capillaries and visceral arterioles, and can be used to treat pulmonary hemorrhage (hemoptysis) and esophageal and gastric fundus varicose vein bleeding (hematemesis).

In addition, vasopressin has a short-term effect of increasing blood pressure and stimulating gastrointestinal smooth muscles. After using posterior pituitary hormone, adverse reactions such as nausea, vomiting, pale complexion, sweating, palpitations, chest tightness, abdominal pain, constipation and allergic reactions may occur. In such cases, the drug should be stopped immediately. It is contraindicated for patients with hypertension, coronary heart disease, cor pulmonale, heart failure, pregnancy-induced hypertension syndrome, etc. For other contraindications, see oxytocin.

3. Aminoergosides

Pharmacological action: It can selectively excite uterine smooth muscle and cause uterine contraction. Its features are:

① Rapid, powerful and long-lasting effect;

② The pregnant uterus is more sensitive than the non-pregnant uterus, especially the uterus during labor and after childbirth;

③ It has no selective effect on the uterine body and cervix, which is not conducive to the delivery of the fetus, so it is forbidden to be used for inducing labor or labor;

④ A slightly larger dose will cause tonic contraction of the uterus, compressing the blood vessels and having a hemostatic effect.