Prostaglandins

Physiological action of prostaglandins:

1. Central nervous system - depression, stupor, catatonia, tremor, irritation and depression of neurons, contracture of the muscles of the limbs.
2. Heart and circulation - increased heart rate and stroke volume, decreased arteriolar tone, increased venous tone, decreased blood pressure, increased calcium content in the heart muscle (cygitalis-like effect).
3. Lungs - decrease in arteriovenous oxygen difference, decrease and increase in bronchial resistance (bronchodilation and bronchoconstriction).
4. Gastrointestinal tract - decreased gastric secretion, stimulation of the motor function of the stomach and intestines.
5. Urogenital system - natriuresis, kaliuresis, increased diuresis, increased urea clearance, stimulation of renin secretion, increase and enhancement of the motor function of the uterus.
6. Endocrine organs - antagonistic effect on the action of insulin, glucagon, corticosteroids and catecholamines.
7. Metabolism - increased glycogen synthesis, increase or decrease in the content of free fatty acids.
8. Blood - influence on the aggregation of red blood cells and platelets, on blood clotting.

Clinical manifestations of prostaglandin action:

Effects of PGE ₂:

• reduces systemic arterial pressure;
• directly dilates small arteries in various organs;
• inhibits the action of pressor hormones;
• improves blood supply to the brain, kidneys, liver, limbs;
• increases glomerular filtration, creatinine clearance;
• reduces the reabsorption of sodium and water in the renal tubules and increases their excretion;
• reduces the initially increased ability of platelets to aggregate;
• improves microcirculation;
• increases blood oxygenation;
• leads to the resorption of fresh ischemic foci in the fundus and reduces the amount of fresh hemorrhages in the retina.

Effects of PGFa2:

• increases systemic arterial pressure, increases arterial pressure in the pulmonary artery;
• reduces blood oxygen saturation;
• reduces blood flow in organs;
• directly increases the tone of the blood vessels of the brain, kidneys, heart, and intestines;
• potentiates the vasoconstrictor effect of pressor hormones;
• increases natriuresis and diuresis.

Since 1970, natural prostaglandins have been used as therapeutic agents in obstetrics and gynecology for cervical ripening and early termination of pregnancy, for the purpose of labor induction and stimulation.

Various routes of administration of prostaglandins have been proposed, however, it has been found that parenteral and oral administration requires relatively large doses of prostaglandins, as they are mainly inactivated in the mother's lungs, and also cause a number of side effects, in particular, nausea, vomiting, diarrhea, tachycardia, pale skin, muscle tremors, allergic reactions, etc.

In recent years, prostaglandins have become increasingly widespread in obstetric practice for local use, as they have the property of “local” hormones.

We recommend intravaginal administration of prostaglandin gel together with carboxymethylcellulose for the following indications:

• in high-risk pregnant women (symptoms of fetal dysfunction, placental insufficiency, etc.), a method has been developed for the combined use of beta-adrenergic agonists (partusisten, alupent, brikanil, ginipral) together with prostaglandins to exclude cases of uterine hyperstimulation or deterioration of the fetus's condition;
• introduction of a gel with prostaglandin in case of untimely discharge of amniotic fluid and an immature cervix;
• for the purpose of treating weak labor activity due to the body’s insufficient readiness for childbirth (ripening or immature cervix).

Contraindications for the use of prostaglandins in obstetric practice:

• organic heart disease;
• arterial hypertension (over 140/90 mm Hg);
• diseases of the respiratory system (bronchial asthma, allergic bronchitis, emphysema, bronchiectasis), active tuberculosis;
• peptic ulcer, ulcerative colitis, severe renal and hepatic dysfunction, epilepsy, glaucoma;
• blood diseases (sickle cell anemia, clotting disorders);
• collagenoses, aggravated allergic history (anaphylaxis in the past);
• previous surgeries on the uterus (caesarean section, conservative myomectomy), uterine fibroids, uterine malformations.

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