Beta-adrenomimetics

Isadrine (isoprenaline, isoproterenol, novodrine). Due to the characteristic stimulating effect on beta-adrenergic receptors, isadrine causes a strong bronchodilator effect, increased heart rate and contractions, increases cardiac output. At the same time, it reduces the total peripheral vascular resistance due to arterial vasoplegia, reduces arterial pressure, and reduces the filling of the ventricles of the heart. The drug increases the myocardium's need for oxygen. Isadrine is not contraindicated in pregnancy. No damaging effects of the drug on the fetus or the mother's body have been identified.

An experimental and clinical justification for the use of beta-adrenergic agonists, in particular isadrine, in the combination therapy of miscarriage was carried out. Pregnant women were prescribed either isadrine alone or isadrine in combination with spasmolytin or no-shpa. Isadrine was given in the form of tablets 0.5-0.25 mg 4 times a day. The effectiveness of the preservative therapy was greatest if pregnant women received isadrine in combination with spasmolytin at a dose of 0.1 mg 3 times a day or no-shpa at a dose of 0.4 mg 2-3 times a day [90 and 85%]. A lesser effect was noted in pregnant women who received isadrine alone (75%). In case of a mild threat of miscarriage, a combination of isadrine with the anticholinergic spasmolytin or a combination of isadrine and no-shpa can be used. The increase in tocolytic effect is explained by the synergistic effect of the combination of two different drugs.

The reduction of side effects caused by isadrine when combined with no-shpa can be explained by the fact that no-shpa selectively acts on beta-adrenoreceptors of the heart, resulting in a decrease in tachycardia. Spasmolitin also reduces the side effects of isadrine, since it causes bradycardia and hypokalemia and thus levels out tachycardia and hyperkalemia caused by isadrine.

Release form: 0.5% and 1% solutions in 25 and 100 ml vials (for inhalation) and tablets or powders containing 0.5 mg of the drug.

Orciprenadium sulfate (alupent, astmopent). The drug is similar to isadrine in chemical structure and pharmacological properties, but does not cause pronounced tachycardia or decreased blood pressure.

Orciprenaline sulfate is not contraindicated during pregnancy. It is most widely used in the treatment of threatened premature labor and uterine hypertonicity during labor. It crosses the placental barrier and can cause tachycardia in the fetus when the dose exceeds 10 mcg/min. In the mother, in therapeutic doses, it does not cause significant side effects; on the contrary, it improves placental perfusion. Positive results have been noted when it is used during labor to treat fetal distress, especially due to abnormal labor or umbilical cord compression. The drug does not have a teratogenic effect.

In case of a pronounced threat of termination of pregnancy, orciprenaline sulfate (alupent) is first used intravenously by drip in a dose of 2-4 ml of a 0.05% solution in a 5% glucose solution at a rate of 20 drops per 1 min. After achieving a tocolytic effect, maintenance therapy is carried out by administering 1 ml 4 times a day intramuscularly.

A separate group consists of pregnant women who receive Alupent according to the above scheme in combination with a 25% solution of magnesium sulfate, 10-20 ml intramuscularly 2-3 times a day. This combination is most effective in 75% of pregnant women.

The state of central hemodynamics was assessed with different methods of alupent administration during labor in the treatment of discoordinated labor. The administration of alupent at a dose of 0.5 mg intramuscularly was compared with the method of microperfusion at a dose of 0.06 mg/h. With intramuscular administration of the drug, abrupt changes in hemodynamics were observed in women in labor, and the use of alupent microperfusion gave less pronounced changes in the main indicators of central hemodynamics, leading to the normalization of contractile activity of the uterus, reducing its basic tone by 2 times.

Long-term use of the drug during pregnancy is possible by prescribing tablets of 0.02 g 3-4 times a day. The effect usually occurs after 1 hour and lasts 4-6 hours.

Release form: aerosol inhalers containing 400 single doses (0.75 mg each) of the drug; ampoules of 1 ml of 0.05% solution (0.5 mg); tablets of 0.02 g.

Terbutaline (terbutaline sulfate, brikanil). Also belongs to the number of adrenomimetics with selective action on beta-adrenergic receptors. Its effect on contractions and tone of the uterus has been studied in detail and it has been established that the drug is advisable to use in case of pronounced symptoms of threatened miscarriage and even in the presence of dilation of the cervix or the onset of premature labor.

According to detailed toxicological studies, brikanil is slightly toxic. Experiments have shown that in doses of 0.02-0.4 mcg/ml it reduces the frequency and amplitude, and in many cases completely stops uterine contractions. Based on the inhibitory effect of brikanil on uterine contractility, it was suggested that it affects the level of prostaglandins, which has been confirmed experimentally.

In physiological labor, intravenous administration of brikanil at a dose of 10-20 mcg/min for 20-45 min effectively blocks spontaneous or oxytocin-induced labor. The intensity of contractions in these cases decreases to a greater extent than their frequency.

In cases of threatened or started premature labor, the drug is usually administered intravenously, dissolving 5 mg of brikanil in 1000 ml of isotonic sodium chloride or glucose solution. It should be taken into account that 20 drops of the solution contain 5 mcg of brikanil and then the dosage of the drug is determined individually, taking into account the severity of its effect and the body's tolerance.

It is usually recommended to start the administration at a rate of 40 drops/min, i.e. 10 mcg/min, then every 10 minutes the rate of administration is increased by 20 drops, reaching 100 drops, i.e. 25 mcg/min. This dosage is maintained for 1 hour, and then every 30 minutes it is reduced by 20 drops, establishing the minimum effective maintenance dose. Usually, on the 2nd-4th day, the drug is administered at a dose of 250 mcg 4 times a day.

According to our research, another method of administering the drug in case of threatened premature labor is also effective, when 0.5 mg of bricanin contained in 1 ml of an aqueous solution is diluted in 500 ml of a 5% glucose solution and administered slowly intravenously in doses of 1.5 to 5 mcg/min. Further therapy is carried out by prescribing bricanin tablets in a dose of 2.5 mg 4-6 times a day. In addition, as the symptoms of threatened premature labor decrease, it is advisable to prescribe bricanin 1 ml intramuscularly, followed by its use in tablet form. The duration of action of bricanin administered parenterally lasts 6-8 hours.

The simultaneous use of Brikanil and MAO inhibitors is not allowed (!), as it can cause a hypertensive crisis. Its simultaneous use with inhalation anesthetics from the fluorine-containing group (fluorotan, etc.), as well as with beta-adrenergic receptor blockers is not recommended, since in this case the substances neutralize each other's action.

Release form: Brikanil tablet contains 2.5 mg of terbutaline sulfate, package contains 20 tablets; Brikanil ampoules contain 0.5 mg of terbutaline sulfate, package contains 10 ampoules.

Ritodrine (Utopar). The drug has no contraindications for use during pregnancy. In terms of duration of action, it is the most effective and has the least pronounced side effects on the cardiovascular system.

Ritodrine effectively inhibits uterine contractions and is successfully used in the treatment of threatened miscarriage, uterine hypertonicity during labor, and fetal acidosis. After its administration, the intensity, frequency, and basal tone of the uterus decrease. In addition, the drug improves the condition of the fetus, judging by the average value of the fetal heartbeat and pH value. Intravenous administration of ritodrine at a dose of 100-600 mcg/min does not have a negative effect on the fetus in the treatment of threatened premature labor. It also does not have a teratogenic effect.

Ritodrine is recommended to be used in doses of 5 to 10 mg 4-6 times a day in the treatment of threatened premature labor. The effectiveness of ritodrine in late toxicosis for the purpose of regulating labor has been demonstrated.

The use of the drug at a dose of 1.5-3 mcg/min has a pronounced therapeutic effect in this group of women in labor, especially in the presence of excessively intense or frequent contractions, as well as with increased basal tone of the uterus and uncoordinated labor.

In the treatment of premature labor, the drug is administered intravenously with an initial dose of 0.05 mg/min, and the dose is gradually increased by 0.05 mg/min every 10 minutes. The clinically effective dose is usually between 0.15 and 0.3 mg/min. The drug is administered for 12 to 48 hours after uterine contractions have ceased.

For intramuscular administration, the initial dose is 10 mg, and if the effect of 10 mg of ritodrine does not occur, then 10 mg is administered again within 1 hour, and then, if there is a risk of termination of pregnancy, 10-20 mg of the drug is administered every 2-6 hours for 12-48 hours. The dose is increased or decreased depending on the clinical effect of ritodrine and possible side effects.

Taking ritodrine tablets orally to consolidate the therapeutic effect is usually done immediately after parenteral administration of the drug at 10 mg every 2-6 hours; the dose can also be increased or decreased depending on the effect and side effects.

In case of severe disturbances of fetal activity caused by uterine hyperactivity, the drug is administered starting with a dose of 0.05 mg/min, gradually increasing it every 15 minutes until uterine activity decreases. The effective dose usually lies between 0.15 and 0.3 mg/kg of body weight. If the fetus has severe acidosis (with a pH of less than 7.10), the use of ritodrine is not recommended.

Contraindications to the use of the drug are massive bleeding during childbirth, diseases in the mother or fetus requiring termination of pregnancy, as well as cardiovascular diseases in the mother. Side effects when taking ritodrine in appropriate doses are insignificant. No unpleasant subjective sensations are observed when the drug is administered very slowly and with the woman lying on her side. Sometimes only a progressive increase in pulse rate and in some cases facial hyperemia, sweating and tremor, as well as nausea and vomiting are noted.

Release form: tablets of 10 mg, 20 tablets per package; ampoules, 10 mg/ml or 50 mg/ml, 6 ampoules per package.

Partusisten (fenoterol). The drug has a pronounced relaxing effect on the uterus. It has a particularly favorable ratio of its high spasmolytic activity and relatively limited effect on the cardiovascular system. It is used in the form of intravenous infusions, as well as orally for the purpose of further consolidation of the therapeutic effect of parenteral administration. Tablets are also used for intermittent treatment according to the relevant indications. A number of modern studies use continuous subcutaneous administration of beta-adrenergic agonists, or in case of severe intolerance, their intravaginal administration.

Indications for the use of partusisten are threatened premature birth, threatened miscarriage after 16 weeks of pregnancy, as well as increased uterine tone after Shirodkar surgery and other surgical interventions performed on the uterus during pregnancy.

During labor, the drug is most often used for abnormalities of labor, especially with hyperactivity of the uterus, increased basal tone, in preparation for operative delivery (caesarean section, obstetric forceps), and with symptoms of incipient fetal asphyxia.

The drug is contraindicated in thyrotoxicosis, various heart diseases, especially heart rhythm disturbances, tachycardia, aortic stenosis, and intrauterine infection.

As a rule, tocolytic treatment is carried out by intravenous continuous drip infusion. In most cases, the optimal parenteral dose of partusisten is 1-3 mcg/min. In some cases, however, it is necessary to reduce the dose to 0.5 or increase it to 4 mcg/min, respectively.

To prepare intravenous infusions, it is recommended to dilute 1 ampoule (10 ml) of partusisten in 250 ml of sterile isotonic sodium chloride solution or 5% glucose or lavulose solution.

In the treatment of threatened premature labor or threatened late miscarriage, oral administration of the drug is recommended at the end of infusion therapy in order to prevent subsequent uterine contractions.

In cases where only one oral treatment is prescribed, it is recommended to use pargusisten 1 tablet (5 mg) every 3-4 hours, i.e. 6-8 tablets daily.

During the use of partusisten, pulse rate and blood pressure, as well as fetal heart rate, should be regularly monitored.

Pregnant women with diabetes should carefully and continuously monitor carbohydrate metabolism, since the use of the drug can lead to a significant increase in blood sugar levels. In such cases, during the use of partusisten, it is necessary to increase the dosage of antidiabetic drugs to prevent such complications. Fetoplacental insufficiency is also an indication for the use of partusisten, since pargusisten improves uteroplacental blood circulation. Pargusisten, even in small doses, has a pronounced antispasmodic effect and, regardless of the dose, leads to a decrease in labor activity and a decrease in basal tone, primarily reducing the amplitude of uterine contractions, and later - their duration and frequency.

When partusisten is administered intravenously, the effect occurs within 10 minutes, when administered orally within 30 minutes, and ceases within 3-4 hours after administration.

In the presence of side effects from the cardiovascular system, isoptin can be additionally prescribed, which reduces or prevents these side effects, and is also a synergist in the effect of partusisten on the uterus. Isoptin together with partusisten can be administered intravenously at a dose of 30-150 mg/min or used orally at a dose of 40-120 mg.

Release form: ampoule (10 ml) contains 0.5 mg of partusisten, 1 tablet - 5 mg (there are 100 tablets in a package, and ampoules are packed in 5 and 25 pieces).

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